space travel time change

Is Time Travel Possible?

We all travel in time! We travel one year in time between birthdays, for example. And we are all traveling in time at approximately the same speed: 1 second per second.

We typically experience time at one second per second. Credit: NASA/JPL-Caltech

NASA's space telescopes also give us a way to look back in time. Telescopes help us see stars and galaxies that are very far away . It takes a long time for the light from faraway galaxies to reach us. So, when we look into the sky with a telescope, we are seeing what those stars and galaxies looked like a very long time ago.

However, when we think of the phrase "time travel," we are usually thinking of traveling faster than 1 second per second. That kind of time travel sounds like something you'd only see in movies or science fiction books. Could it be real? Science says yes!

This image from the Hubble Space Telescope shows galaxies that are very far away as they existed a very long time ago. Credit: NASA, ESA and R. Thompson (Univ. Arizona)

How do we know that time travel is possible?

More than 100 years ago, a famous scientist named Albert Einstein came up with an idea about how time works. He called it relativity. This theory says that time and space are linked together. Einstein also said our universe has a speed limit: nothing can travel faster than the speed of light (186,000 miles per second).

Einstein's theory of relativity says that space and time are linked together. Credit: NASA/JPL-Caltech

What does this mean for time travel? Well, according to this theory, the faster you travel, the slower you experience time. Scientists have done some experiments to show that this is true.

For example, there was an experiment that used two clocks set to the exact same time. One clock stayed on Earth, while the other flew in an airplane (going in the same direction Earth rotates).

After the airplane flew around the world, scientists compared the two clocks. The clock on the fast-moving airplane was slightly behind the clock on the ground. So, the clock on the airplane was traveling slightly slower in time than 1 second per second.

Credit: NASA/JPL-Caltech

Can we use time travel in everyday life?

We can't use a time machine to travel hundreds of years into the past or future. That kind of time travel only happens in books and movies. But the math of time travel does affect the things we use every day.

For example, we use GPS satellites to help us figure out how to get to new places. (Check out our video about how GPS satellites work .) NASA scientists also use a high-accuracy version of GPS to keep track of where satellites are in space. But did you know that GPS relies on time-travel calculations to help you get around town?

GPS satellites orbit around Earth very quickly at about 8,700 miles (14,000 kilometers) per hour. This slows down GPS satellite clocks by a small fraction of a second (similar to the airplane example above).

GPS satellites orbit around Earth at about 8,700 miles (14,000 kilometers) per hour. Credit: GPS.gov

However, the satellites are also orbiting Earth about 12,550 miles (20,200 km) above the surface. This actually speeds up GPS satellite clocks by a slighter larger fraction of a second.

Here's how: Einstein's theory also says that gravity curves space and time, causing the passage of time to slow down. High up where the satellites orbit, Earth's gravity is much weaker. This causes the clocks on GPS satellites to run faster than clocks on the ground.

The combined result is that the clocks on GPS satellites experience time at a rate slightly faster than 1 second per second. Luckily, scientists can use math to correct these differences in time.

If scientists didn't correct the GPS clocks, there would be big problems. GPS satellites wouldn't be able to correctly calculate their position or yours. The errors would add up to a few miles each day, which is a big deal. GPS maps might think your home is nowhere near where it actually is!

In Summary:

Yes, time travel is indeed a real thing. But it's not quite what you've probably seen in the movies. Under certain conditions, it is possible to experience time passing at a different rate than 1 second per second. And there are important reasons why we need to understand this real-world form of time travel.

If you liked this, you may like:

• Skip to main content
• Keyboard shortcuts for audio player

• LISTEN & FOLLOW
• Apple Podcasts
• Google Podcasts
• Amazon Music
• Amazon Alexa

Your support helps make our show possible and unlocks access to our sponsor-free feed.

Paradox-Free Time Travel Is Theoretically Possible, Researchers Say

Matthew S. Schwartz

A dog dressed as Marty McFly from Back to the Future attends the Tompkins Square Halloween Dog Parade in 2015. New research says time travel might be possible without the problems McFly encountered. Timothy A. Clary/AFP via Getty Images hide caption

A dog dressed as Marty McFly from Back to the Future attends the Tompkins Square Halloween Dog Parade in 2015. New research says time travel might be possible without the problems McFly encountered.

"The past is obdurate," Stephen King wrote in his book about a man who goes back in time to prevent the Kennedy assassination. "It doesn't want to be changed."

Turns out, King might have been on to something.

Countless science fiction tales have explored the paradox of what would happen if you went back in time and did something in the past that endangered the future. Perhaps one of the most famous pop culture examples is in Back to the Future , when Marty McFly goes back in time and accidentally stops his parents from meeting, putting his own existence in jeopardy.

But maybe McFly wasn't in much danger after all. According a new paper from researchers at the University of Queensland, even if time travel were possible, the paradox couldn't actually exist.

Researchers ran the numbers and determined that even if you made a change in the past, the timeline would essentially self-correct, ensuring that whatever happened to send you back in time would still happen.

"Say you traveled in time in an attempt to stop COVID-19's patient zero from being exposed to the virus," University of Queensland scientist Fabio Costa told the university's news service .

"However, if you stopped that individual from becoming infected, that would eliminate the motivation for you to go back and stop the pandemic in the first place," said Costa, who co-authored the paper with honors undergraduate student Germain Tobar.

"This is a paradox — an inconsistency that often leads people to think that time travel cannot occur in our universe."

A variation is known as the "grandfather paradox" — in which a time traveler kills their own grandfather, in the process preventing the time traveler's birth.

The logical paradox has given researchers a headache, in part because according to Einstein's theory of general relativity, "closed timelike curves" are possible, theoretically allowing an observer to travel back in time and interact with their past self — potentially endangering their own existence.

But these researchers say that such a paradox wouldn't necessarily exist, because events would adjust themselves.

Take the coronavirus patient zero example. "You might try and stop patient zero from becoming infected, but in doing so, you would catch the virus and become patient zero, or someone else would," Tobar told the university's news service.

In other words, a time traveler could make changes, but the original outcome would still find a way to happen — maybe not the same way it happened in the first timeline but close enough so that the time traveler would still exist and would still be motivated to go back in time.

"No matter what you did, the salient events would just recalibrate around you," Tobar said.

The paper, "Reversible dynamics with closed time-like curves and freedom of choice," was published last week in the peer-reviewed journal Classical and Quantum Gravity . The findings seem consistent with another time travel study published this summer in the peer-reviewed journal Physical Review Letters. That study found that changes made in the past won't drastically alter the future.

Bestselling science fiction author Blake Crouch, who has written extensively about time travel, said the new study seems to support what certain time travel tropes have posited all along.

"The universe is deterministic and attempts to alter Past Event X are destined to be the forces which bring Past Event X into being," Crouch told NPR via email. "So the future can affect the past. Or maybe time is just an illusion. But I guess it's cool that the math checks out."

• time travel
• grandfather paradox

Time travel: Is it possible?

Science says time travel is possible, but probably not in the way you're thinking.

Albert Einstein's theory

• General relativity and GPS
• Wormhole travel
• Alternate theories

Science fiction

Is time travel possible? Short answer: Yes, and you're doing it right now — hurtling into the future at the impressive rate of one second per second. 

You're pretty much always moving through time at the same speed, whether you're watching paint dry or wishing you had more hours to visit with a friend from out of town. 

But this isn't the kind of time travel that's captivated countless science fiction writers, or spurred a genre so extensive that Wikipedia lists over 400 titles in the category "Movies about Time Travel." In franchises like " Doctor Who ," " Star Trek ," and "Back to the Future" characters climb into some wild vehicle to blast into the past or spin into the future. Once the characters have traveled through time, they grapple with what happens if you change the past or present based on information from the future (which is where time travel stories intersect with the idea of parallel universes or alternate timelines). 

Related: The best sci-fi time machines ever

Although many people are fascinated by the idea of changing the past or seeing the future before it's due, no person has ever demonstrated the kind of back-and-forth time travel seen in science fiction or proposed a method of sending a person through significant periods of time that wouldn't destroy them on the way. And, as physicist Stephen Hawking pointed out in his book " Black Holes and Baby Universes" (Bantam, 1994), "The best evidence we have that time travel is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future."

Science does support some amount of time-bending, though. For example, physicist Albert Einstein 's theory of special relativity proposes that time is an illusion that moves relative to an observer. An observer traveling near the speed of light will experience time, with all its aftereffects (boredom, aging, etc.) much more slowly than an observer at rest. That's why astronaut Scott Kelly aged ever so slightly less over the course of a year in orbit than his twin brother who stayed here on Earth. 

Related: Controversially, physicist argues that time is real

There are other scientific theories about time travel, including some weird physics that arise around wormholes , black holes and string theory . For the most part, though, time travel remains the domain of an ever-growing array of science fiction books, movies, television shows, comics, video games and more. 

Einstein developed his theory of special relativity in 1905. Along with his later expansion, the theory of general relativity , it has become one of the foundational tenets of modern physics. Special relativity describes the relationship between space and time for objects moving at constant speeds in a straight line. 

The short version of the theory is deceptively simple. First, all things are measured in relation to something else — that is to say, there is no "absolute" frame of reference. Second, the speed of light is constant. It stays the same no matter what, and no matter where it's measured from. And third, nothing can go faster than the speed of light.

From those simple tenets unfolds actual, real-life time travel. An observer traveling at high velocity will experience time at a slower rate than an observer who isn't speeding through space. 

While we don't accelerate humans to near-light-speed, we do send them swinging around the planet at 17,500 mph (28,160 km/h) aboard the International Space Station . Astronaut Scott Kelly was born after his twin brother, and fellow astronaut, Mark Kelly . Scott Kelly spent 520 days in orbit, while Mark logged 54 days in space. The difference in the speed at which they experienced time over the course of their lifetimes has actually widened the age gap between the two men.

"So, where[as] I used to be just 6 minutes older, now I am 6 minutes and 5 milliseconds older," Mark Kelly said in a panel discussion on July 12, 2020, Space.com previously reported . "Now I've got that over his head."

General relativity and GPS time travel

The difference that low earth orbit makes in an astronaut's life span may be negligible — better suited for jokes among siblings than actual life extension or visiting the distant future — but the dilation in time between people on Earth and GPS satellites flying through space does make a difference. 

Read more: Can we stop time?

The Global Positioning System , or GPS, helps us know exactly where we are by communicating with a network of a few dozen satellites positioned in a high Earth orbit. The satellites circle the planet from 12,500 miles (20,100 kilometers) away, moving at 8,700 mph (14,000 km/h). 

According to special relativity, the faster an object moves relative to another object, the slower that first object experiences time. For GPS satellites with atomic clocks, this effect cuts 7 microseconds, or 7 millionths of a second, off each day, according to the American Physical Society publication Physics Central .  

Read more: Could Star Trek's faster-than-light warp drive actually work?

Then, according to general relativity, clocks closer to the center of a large gravitational mass like Earth tick more slowly than those farther away. So, because the GPS satellites are much farther from the center of Earth compared to clocks on the surface, Physics Central added, that adds another 45 microseconds onto the GPS satellite clocks each day. Combined with the negative 7 microseconds from the special relativity calculation, the net result is an added 38 microseconds. 

This means that in order to maintain the accuracy needed to pinpoint your car or phone — or, since the system is run by the U.S. Department of Defense, a military drone — engineers must account for an extra 38 microseconds in each satellite's day. The atomic clocks onboard don’t tick over to the next day until they have run 38 microseconds longer than comparable clocks on Earth.

Given those numbers, it would take more than seven years for the atomic clock in a GPS satellite to un-sync itself from an Earth clock by more than a blink of an eye. (We did the math: If you estimate a blink to last at least 100,000 microseconds, as the Harvard Database of Useful Biological Numbers does, it would take thousands of days for those 38 microsecond shifts to add up.) 

This kind of time travel may seem as negligible as the Kelly brothers' age gap, but given the hyper-accuracy of modern GPS technology, it actually does matter. If it can communicate with the satellites whizzing overhead, your phone can nail down your location in space and time with incredible accuracy. 

Can wormholes take us back in time?

General relativity might also provide scenarios that could allow travelers to go back in time, according to NASA . But the physical reality of those time-travel methods is no piece of cake. 

Wormholes are theoretical "tunnels" through the fabric of space-time that could connect different moments or locations in reality to others. Also known as Einstein-Rosen bridges or white holes, as opposed to black holes, speculation about wormholes abounds. But despite taking up a lot of space (or space-time) in science fiction, no wormholes of any kind have been identified in real life. 

Related: Best time travel movies

"The whole thing is very hypothetical at this point," Stephen Hsu, a professor of theoretical physics at the University of Oregon, told Space.com sister site Live Science . "No one thinks we're going to find a wormhole anytime soon."

Primordial wormholes are predicted to be just 10^-34 inches (10^-33 centimeters) at the tunnel's "mouth". Previously, they were expected to be too unstable for anything to be able to travel through them. However, a study claims that this is not the case, Live Science reported . 

The theory, which suggests that wormholes could work as viable space-time shortcuts, was described by physicist Pascal Koiran. As part of the study, Koiran used the Eddington-Finkelstein metric, as opposed to the Schwarzschild metric which has been used in the majority of previous analyses.

In the past, the path of a particle could not be traced through a hypothetical wormhole. However, using the Eddington-Finkelstein metric, the physicist was able to achieve just that.

Koiran's paper was described in October 2021, in the preprint database arXiv , before being published in the Journal of Modern Physics D.

Alternate time travel theories

While Einstein's theories appear to make time travel difficult, some researchers have proposed other solutions that could allow jumps back and forth in time. These alternate theories share one major flaw: As far as scientists can tell, there's no way a person could survive the kind of gravitational pulling and pushing that each solution requires.

Infinite cylinder theory

Astronomer Frank Tipler proposed a mechanism (sometimes known as a Tipler Cylinder ) where one could take matter that is 10 times the sun's mass, then roll it into a very long, but very dense cylinder. The Anderson Institute , a time travel research organization, described the cylinder as "a black hole that has passed through a spaghetti factory."

After spinning this black hole spaghetti a few billion revolutions per minute, a spaceship nearby — following a very precise spiral around the cylinder — could travel backward in time on a "closed, time-like curve," according to the Anderson Institute. 

The major problem is that in order for the Tipler Cylinder to become reality, the cylinder would need to be infinitely long or be made of some unknown kind of matter. At least for the foreseeable future, endless interstellar pasta is beyond our reach.

Time donuts

Theoretical physicist Amos Ori at the Technion-Israel Institute of Technology in Haifa, Israel, proposed a model for a time machine made out of curved space-time — a donut-shaped vacuum surrounded by a sphere of normal matter.

"The machine is space-time itself," Ori told Live Science . "If we were to create an area with a warp like this in space that would enable time lines to close on themselves, it might enable future generations to return to visit our time."

Amos Ori is a theoretical physicist at the Technion-Israel Institute of Technology in Haifa, Israel. His research interests and publications span the fields of general relativity, black holes, gravitational waves and closed time lines.

There are a few caveats to Ori's time machine. First, visitors to the past wouldn't be able to travel to times earlier than the invention and construction of the time donut. Second, and more importantly, the invention and construction of this machine would depend on our ability to manipulate gravitational fields at will — a feat that may be theoretically possible but is certainly beyond our immediate reach.

Time travel has long occupied a significant place in fiction. Since as early as the "Mahabharata," an ancient Sanskrit epic poem compiled around 400 B.C., humans have dreamed of warping time, Lisa Yaszek, a professor of science fiction studies at the Georgia Institute of Technology in Atlanta, told Live Science .  

Every work of time-travel fiction creates its own version of space-time, glossing over one or more scientific hurdles and paradoxes to achieve its plot requirements. 

Some make a nod to research and physics, like " Interstellar ," a 2014 film directed by Christopher Nolan. In the movie, a character played by Matthew McConaughey spends a few hours on a planet orbiting a supermassive black hole, but because of time dilation, observers on Earth experience those hours as a matter of decades. 

Others take a more whimsical approach, like the "Doctor Who" television series. The series features the Doctor, an extraterrestrial "Time Lord" who travels in a spaceship resembling a blue British police box. "People assume," the Doctor explained in the show, "that time is a strict progression from cause to effect, but actually from a non-linear, non-subjective viewpoint, it's more like a big ball of wibbly-wobbly, timey-wimey stuff." 

Long-standing franchises like the "Star Trek" movies and television series, as well as comic universes like DC and Marvel Comics, revisit the idea of time travel over and over. 

Related: Marvel movies in order: chronological & release order

Here is an incomplete (and deeply subjective) list of some influential or notable works of time travel fiction:

Books about time travel:

• Rip Van Winkle (Cornelius S. Van Winkle, 1819) by Washington Irving
• A Christmas Carol (Chapman & Hall, 1843) by Charles Dickens
• The Time Machine (William Heinemann, 1895) by H. G. Wells
• A Connecticut Yankee in King Arthur's Court (Charles L. Webster and Co., 1889) by Mark Twain
• The Restaurant at the End of the Universe (Pan Books, 1980) by Douglas Adams
• A Tale of Time City (Methuen, 1987) by Diana Wynn Jones
• The Outlander series (Delacorte Press, 1991-present) by Diana Gabaldon
• Harry Potter and the Prisoner of Azkaban (Bloomsbury/Scholastic, 1999) by J. K. Rowling
• Thief of Time (Doubleday, 2001) by Terry Pratchett
• The Time Traveler's Wife (MacAdam/Cage, 2003) by Audrey Niffenegger
• All You Need is Kill (Shueisha, 2004) by Hiroshi Sakurazaka

Movies about time travel:

• Planet of the Apes (1968)
• Superman (1978)
• Time Bandits (1981)
• The Terminator (1984)
• Back to the Future series (1985, 1989, 1990)
• Star Trek IV: The Voyage Home (1986)
• Bill & Ted's Excellent Adventure (1989)
• Groundhog Day (1993)
• Galaxy Quest (1999)
• The Butterfly Effect (2004)
• 13 Going on 30 (2004)
• The Lake House (2006)
• Meet the Robinsons (2007)
• Hot Tub Time Machine (2010)
• Midnight in Paris (2011)
• Looper (2012)
• X-Men: Days of Future Past (2014)
• Edge of Tomorrow (2014)
• Interstellar (2014)
• Doctor Strange (2016)
• A Wrinkle in Time (2018)
• The Last Sharknado: It's About Time (2018)
• Avengers: Endgame (2019)
• Tenet (2020)
• Palm Springs (2020)
• Zach Snyder's Justice League (2021)
• The Tomorrow War (2021)

Television about time travel:

• Doctor Who (1963-present)
• The Twilight Zone (1959-1964) (multiple episodes)
• Star Trek (multiple series, multiple episodes)
• Samurai Jack (2001-2004)
• Lost (2004-2010)
• Phil of the Future (2004-2006)
• Steins;Gate (2011)
• Outlander (2014-2023)
• Loki (2021-present)

Games about time travel:

• Chrono Trigger (1995)
• TimeSplitters (2000-2005)
• Kingdom Hearts (2002-2019)
• Prince of Persia: Sands of Time (2003)
• God of War II (2007)
• Ratchet and Clank Future: A Crack In Time (2009)
• Sly Cooper: Thieves in Time (2013)
• Dishonored 2 (2016)
• Titanfall 2 (2016)
• Outer Wilds (2019)

Additional resources

Explore physicist Peter Millington's thoughts about Stephen Hawking's time travel theories at The Conversation . Check out a kid-friendly explanation of real-world time travel from NASA's Space Place . For an overview of time travel in fiction and the collective consciousness, read " Time Travel: A History " (Pantheon, 2016) by James Gleik. 

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: [email protected].

Get the Space.com Newsletter

Breaking space news, the latest updates on rocket launches, skywatching events and more!

Ailsa is a staff writer for How It Works magazine, where she writes science, technology, space, history and environment features. Based in the U.K., she graduated from the University of Stirling with a BA (Hons) journalism degree. Previously, Ailsa has written for Cardiff Times magazine, Psychology Now and numerous science bookazines. 

China launches Chang'e 6 sample-return mission to moon's far side (video)

A Switzerland-size hole opened in Antarctica's sea ice in 2016-17. Now we know why

'Lost' satellite found after orbiting undetected for 25 years

Most Popular

• 2 Boeing's Starliner is a 'big piece of America's overall strategy for access to low Earth orbit,' astronaut says
• 3 Handle Mars with care: Guidelines needed for responsible Red Planet exploration, experts say
• 4 NASA astronaut and director Ellen Ochoa awarded Presidential Medal of Freedom
• 5 Happy National Astronaut Day 2024! Holiday's founder talks importance of honoring America's spaceflyers (exclusive)

Time Travel: Observing Cosmic History

By observing light from faraway cosmic objects, the Hubble Space Telescope is like a time machine. Light takes time to reach Hubble, because it travels great distances. That means images captured by Hubble today, show what the objects looked like years ago!

The Hubble Space Telescope is many things. It’s an observatory, a satellite, and an icon of cultural and scientific significance – but perhaps most interestingly, Hubble is also a time machine.

Hubble isn’t that far away, locked in a low-Earth orbit just a few hundred miles up that takes about 90 minutes to complete. But with its position just above Earth’s murky atmosphere, Hubble’s transformative view of our universe literally lets us witness our universe’s past.  It allows us to effectively travel back in time.

How does that work? After all, Hubble doesn’t travel beyond our solar system, or even our home planet’s gravity. It certainly doesn’t have any sci-fi elements you might find in Doctor Who or Back to the Future.

Light Travel

The answer is simply light.

The term “light-year” shows up a lot in astronomy. This is a measure of distance that means exactly what it says – the distance that light travels in one year. Given that the speed of light is 186,000 miles (299,000 kilometers) per second, light can cover some serious ground over the course of 365 days. To be precise, almost 6 trillion miles (9.5 trillion kilometers)!

Traveling Back in Time: 8 minutes

Hubble works by gathering light from objects in our universe – some as close as our Moon, and some as distant as galaxy clusters that are billions of light-years away. All that light takes time to reach the telescope, just as it takes time for light to travel from its source to our eyes. For example, our Sun is located about 93 million miles (150 million kilometers) from Earth. That means that it takes roughly eight minutes for its light to reach us here on our planet, so when we look at the Sun (though directly is never recommended!) we see it exactly as it was eight minutes in the past.

Cosmically speaking, the 93 million miles between us and the Sun are nothing. We orbit around just one of billions of stars in the Milky Way Galaxy, which is one of countless trillions of galaxies in the universe.

With that in mind, time travel gets more intense when Hubble observes objects beyond our star system.

Traveling Back in Time: 4 years

Aside from our Sun, the next closest star to us is named Proxima Centauri. It’s about four light-years away, which makes it a close neighbor on a universal scale. But even with Hubble’s sharp, powerful vision, Proxima Centauri remains a point-like object – demonstrating our universe’s unfathomably large size.

Traveling Back in Time: 700 years

Another stellar target of Hubble’s is named Betelgeuse, which is about 700 light-years from Earth. Again, this means that when Hubble looks at Betelgeuse, the star appears exactly as it was 700 years ago. As one of the brightest stars in our sky, astronomers believe it’s likely that even the earliest humans knew of it, as this star appears in stories from several cultures.

This red supergiant star began to dim significantly in the fall of 2019, losing about 60% of its brightness within months. But by April 2020, its regular brightness returned. Hubble studied Betelgeuse and found out that the star “blew its top” – it went through a surface mass ejection, in which the star spewed out a large amount of its surface material into space. When that material in space cooled down, it became a dust cloud that temporarily blocked some of the star’s light.

Hubble’s unique ability to observe in ultraviolet light helped reveal the details of this dimming event and its aftermath. In this range of light, Hubble can better observe the hot layers of atmosphere above a star’s surface.

The telescope continues to be the go-to observatory for scientists who study Betelgeuse. Because it’s taken this long for the light from Betelgeuse to reach us, only in very recent history have we witnessed a cosmic event unfolding that really occurred about 700 years ago!

Scientists also believe that Betelgeuse is on the verge of going supernova – dying in an explosive event. In fact, it may have already done so, but the light from the explosion still hasn’t reached us. There’s a good chance that Betelgeuse no longer exists, though we can still see it today from Earth.

Traveling Back in Time: 6,500 years

Nebulae are clouds of gas and dust where stars are birthed, or the remnants of a dead or dying star itself. These beautiful, ethereal cosmic objects are the subject of some of Hubble’s most iconic images, but they can also teach us more about how our universe behaves and evolves.

For example, a favorite target for Hubble is the Crab Nebula, located about 6,500 light-years away. There are records from 1054 CE written by Chinese astronomers noting the new presence of a shockingly bright “guest” star in the sky, visible even during the daytime. Turns out, they actually saw a supernova – a star’s explosive death – which became the Crab Nebula, made up by the remnants of this violent event. Of course, those Chinese astronomers witnessed a supernova explosion that occurred about 5446 BCE, but it took the light from the explosion 6,500 years to reach Earth in the year 1054.

Traveling Back in Time: 2.5 million years

When Hubble looks beyond our own galaxy, we can watch cosmic history unfold over eons.

The Andromeda Galaxy is a whopping 2.5 million light-years away, but that’s just the closest major galaxy to us here in the Milky Way. Observing Andromeda is like staring into a vision from 2.5 million years ago – back during the Paleolithic period on Earth, when very early humans existed.

And if Andromeda is the closest major galaxy to us, it’s difficult to comprehend just how far the light from the most distant observed galaxies has traveled.

Traveling Back in Time: 12.9 billion years

Another Hubble record is for observing the most distant individual star ever detected, named Earendel. This faraway star emitted its light within the first billion years of the universe, which is about 13.8 billion years old, so it took quite a while to reach Hubble! In fact, that observation was only made possible by nature’s magnifying glass – an astronomical phenomenon known as gravitational lensing. When a massive cosmic object has enough gravity, its gravitational field can magnify and bend light coming from objects located behind it. The gravity of a galaxy cluster located between Hubble and Earendel magnified the star’s light, making it detectable.  The type of star that Earendel seems to be typically have brief lives, only surviving about half a billion years. That means Earendel has ceased to exist for over 12 billion years, yet we are able to look back in time and watch Earendel during its short life.

Traveling Back in Time: 13.4 billion years

Perhaps some of Hubble’s most legendary observations are its deep field images, which collect light from thousands of galaxies that are billions of light-years away.

With this type of imagery, we can better understand how our universe changes over time by puzzling out how galaxies evolve. The farther back we look with Hubble, the closer we get to the the big bang, when the universe began – so the most distant galaxies observed by Hubble often appear to us as the “youngest” ones – giving us a sneak peek at the universe in its infancy. Because these galaxies emitted their light when they were young, we get to witness them in their early stages. These early galaxies often appear simpler and smaller than the grandiose spiral galaxies and merged galaxies we see closer to us in distance, and therefore in time. These young galaxies are actually old galaxies now as they have evolved over the time this light has taken to reach us.

Hubble’s farthest observation is of a galaxy named GN-z11, observed as it was 13.4 billion years in the past! This places it within just 400 million years of the big bang itself.

Watching Our Universe Over Time

Observations of the most distant objects, like GN-z11 and Earendel, give astronomers exciting insight into the environment of our early universe. The light we see literally traveled from all the way back then!

Our universe remains mysterious, mind-bendingly large, and ever-expanding, but by gathering light from near and far – from the recent past to the dawn of the universe itself – Hubble helps answer questions about where we are and how the universe works.

At its core, astronomy is really just archaeology. Cosmic objects give off light, letting us learn more about their lives. It can take a long, long time for light to reach Hubble – just one telescope orbiting just one planet in just one solar system in just one galaxy. Scientists use Hubble like the time machine that it is to piece together the history and mystery of the cosmos, giving us all a glimpse right up to the edge of the universe – and time itself.

Explore More Hubble

The Lost Universe

NASA's Hubble Space Telescope has vanished from Earth’s timeline. Only an ambitious crew of adventurers can uncover what was lost. Are you up to the challenge?

Hubble Science Highlights

Hubble has affected every area of astronomy. Its most notable scientific discoveries reflect the broad range of research and the breakthroughs it has achieved.

Hubble's Cultural Impact

Even if you don't know anything about the Hubble Space Telescope, its pictures have been a part of your life.

What is Hubble Observing?

See the area of sky Hubble is currently investigating or explore its upcoming and past targets.

Hubble E-books

Investigate the mysteries of the universe with Hubble. Learn Hubble's history and dive deeper into its discoveries by downloading our e-books.

Why does time change when traveling close to the speed of light? A physicist explains

Assistant Professor of Physics and Astronomy, Rochester Institute of Technology

Disclosure statement

Michael Lam does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Rochester Institute of Technology provides funding as a member of The Conversation US.

View all partners

• Bahasa Indonesia

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected] .

Why does time change when traveling close to the speed of light? – Timothy, age 11, Shoreview, Minnesota

Imagine you’re in a car driving across the country watching the landscape. A tree in the distance gets closer to your car, passes right by you, then moves off again in the distance behind you.

Of course, you know that tree isn’t actually getting up and walking toward or away from you. It’s you in the car who’s moving toward the tree. The tree is moving only in comparison, or relative, to you – that’s what we physicists call relativity . If you had a friend standing by the tree, they would see you moving toward them at the same speed that you see them moving toward you.

In his 1632 book “ Dialogue Concerning the Two Chief World Systems ,” the astronomer Galileo Galilei first described the principle of relativity – the idea that the universe should behave the same way at all times, even if two people experience an event differently because one is moving in respect to the other.

If you are in a car and toss a ball up in the air, the physical laws acting on it, such as the force of gravity, should be the same as the ones acting on an observer watching from the side of the road. However, while you see the ball as moving up and back down, someone on the side of the road will see it moving toward or away from them as well as up and down.

Special relativity and the speed of light

Albert Einstein much later proposed the idea of what’s now known as special relativity to explain some confusing observations that didn’t have an intuitive explanation at the time. Einstein used the work of many physicists and astronomers in the late 1800s to put together his theory in 1905, starting with two key ingredients: the principle of relativity and the strange observation that the speed of light is the same for every observer and nothing can move faster. Everyone measuring the speed of light will get the same result, no matter where they are or how fast they are moving.

Let’s say you’re in the car driving at 60 miles per hour and your friend is standing by the tree. When they throw a ball toward you at a speed of what they perceive to be 60 miles per hour, you might logically think that you would observe your friend and the tree moving toward you at 60 miles per hour and the ball moving toward you at 120 miles per hour. While that’s really close to the correct value, it’s actually slightly wrong.

This discrepancy between what you might expect by adding the two numbers and the true answer grows as one or both of you move closer to the speed of light. If you were traveling in a rocket moving at 75% of the speed of light and your friend throws the ball at the same speed, you would not see the ball moving toward you at 150% of the speed of light. This is because nothing can move faster than light – the ball would still appear to be moving toward you at less than the speed of light. While this all may seem very strange, there is lots of experimental evidence to back up these observations.

Time dilation and the twin paradox

Speed is not the only factor that changes relative to who is making the observation. Another consequence of relativity is the concept of time dilation , whereby people measure different amounts of time passing depending on how fast they move relative to one another.

Each person experiences time normally relative to themselves. But the person moving faster experiences less time passing for them than the person moving slower. It’s only when they reconnect and compare their watches that they realize that one watch says less time has passed while the other says more.

This leads to one of the strangest results of relativity – the twin paradox , which says that if one of a pair of twins makes a trip into space on a high-speed rocket, they will return to Earth to find their twin has aged faster than they have. It’s important to note that time behaves “normally” as perceived by each twin (exactly as you are experiencing time now), even if their measurements disagree.

You might be wondering: If each twin sees themselves as stationary and the other as moving toward them, wouldn’t they each measure the other as aging faster? The answer is no, because they can’t both be older relative to the other twin.

The twin on the spaceship is not only moving at a particular speed where the frame of references stay the same but also accelerating compared with the twin on Earth. Unlike speeds that are relative to the observer, accelerations are absolute. If you step on a scale, the weight you are measuring is actually your acceleration due to gravity. This measurement stays the same regardless of the speed at which the Earth is moving through the solar system, or the solar system is moving through the galaxy or the galaxy through the universe.

Neither twin experiences any strangeness with their watches as one moves closer to the speed of light – they both experience time as normally as you or I do. It’s only when they meet up and compare their observations that they will see a difference – one that is perfectly defined by the mathematics of relativity.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to [email protected] . Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

• General Relativity
• Special Relativity
• Time dilation
• Speed of light
• Albert Einstein
• Curious Kids
• Theory of relativity
• Curious Kids US

Scheduling Analyst

Assistant Editor - 1 year cadetship

Executive Dean, Faculty of Health

Lecturer/Senior Lecturer, Earth System Science (School of Science)

Sydney Horizon Educators (Identified)

MIT Technology Review

• Newsletters

Would you really age more slowly on a spaceship at close to light speed?

• Neel V. Patel archive page

Every week, the readers of our space newsletter, The Airlock , send in their questions for space reporter Neel V. Patel to answer. This week: time dilation during space travel. 

I heard that time dilation affects high-speed space travel and I am wondering the magnitude of that affect. If we were to launch a round-trip flight to a nearby exoplanet—let's say 10 or 50 light-years away––how would that affect time for humans on the spaceship versus humans on Earth? When the space travelers came back, will they be much younger or older relative to people who stayed on Earth? —Serge

Time dilation is a concept that pops up in lots of sci-fi, including Orson Scott Card’s Ender’s Game , where one character ages only eight years in space while 50 years pass on Earth. This is precisely the scenario outlined in the famous thought experiment the Twin Paradox : an astronaut with an identical twin at mission control makes a journey into space on a high-speed rocket and returns home to find that the twin has aged faster.

Time dilation goes back to Einstein’s theory of special relativity, which teaches us that motion through space actually creates alterations in the flow of time. The faster you move through the three dimensions that define physical space, the more slowly you’re moving through the fourth dimension, time––at least relative to another object. Time is measured differently for the twin who moved through space and the twin who stayed on Earth. The clock in motion will tick more slowly than the clocks we’re watching on Earth. If you’re able to travel near the speed of light, the effects are much more pronounced. 

Unlike the Twin Paradox, time dilation isn’t a thought experiment or a hypothetical concept––it’s real. The 1971 Hafele-Keating experiments proved as much, when two atomic clocks were flown on planes traveling in opposite directions. The relative motion actually had a measurable impact and created a time difference between the two clocks. This has also been confirmed in other physics experiments (e.g., fast-moving muon particles take longer to decay ). 

So in your question, an astronaut returning from a space journey at “relativistic speeds” (where the effects of relativity start to manifest—generally at least one-tenth the speed of light ) would, upon return, be younger than same-age friends and family who stayed on Earth. Exactly how much younger depends on exactly how fast the spacecraft had been moving and accelerating, so it’s not something we can readily answer. But if you’re trying to reach an exoplanet 10 to 50 light-years away and still make it home before you yourself die of old age, you’d have to be moving at close to light speed. 

There’s another wrinkle here worth mentioning: time dilation as a result of gravitational effects. You might have seen Christopher Nolan’s movie Interstellar , where the close proximity of a black hole causes time on another planet to slow down tremendously (one hour on that planet is seven Earth years).

This form of time dilation is also real, and it’s because in Einstein’s theory of general relativity, gravity can bend spacetime, and therefore time itself. The closer the clock is to the source of gravitation, the slower time passes; the farther away the clock is from gravity, the faster time will pass. (We can save the details of that explanation for a future Airlock.)

Amplifying space’s potential with quantum

How to safely watch and photograph the total solar eclipse.

The solar eclipse this Monday, April 8, will be visible to millions. Here’s how to make the most of your experience.

• Rhiannon Williams archive page

The great commercial takeover of low Earth orbit

Axiom Space and other companies are betting they can build private structures to replace the International Space Station.

• David W. Brown archive page

The race to fix space-weather forecasting before next big solar storm hits

Solar activity can knock satellites off track, raising the risk of collisions. Scientists are hoping improved atmospheric models will help.

• Tereza Pultarova archive page

Stay connected

Get the latest updates from mit technology review.

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at [email protected] with a list of newsletters you’d like to receive.

Why does NASA want a time zone on the moon?

NASA has been tasked with determining a standard time zone for the moon, but it’s more complicated than you might think.

The United States government has tasked its space agency, NASA, with establishing a standard time zone for the moon, which will be known as Coordinated Lunar Time (CLT).

In a memo issued on April 2, the US Office of Science and Technology Policy (OSTP) stated: “Federal agencies will develop celestial time standardisation with an initial focus on the lunar surface and missions operating in Cislunar space [the area within the moon’s orbit], with sufficient traceability to support missions to other celestial bodies.” “Traceability” means that CLT can be kept in sync with time zones on Earth.

Keep reading

Boeing postpones launch of starliner space capsule after technical fault, china launches chang’e-6 probe to study dark side of the moon, china launches historic mission to far side of the moon, russia’s angara a5 rocket blasts off into space after two aborted launches.

The memo outlined the following features for the new CLT:

• Traceability to Coordinated Universal Time (UTC – a compromise for both English and French speakers);
• Accuracy sufficient to support precision navigation and science;
• Resilience to loss of contact with Earth (meaning CLT can operate independently of Earth); and
• Scalability to space environments beyond the Earth-moon system (meaning other space stations beyond the moon would be able to use CLT as well).

Don’t expect your favourite time zone and calendar apps to have CLT as an option yet; NASA has until the end of 2026 to establish CLT.

Why does the moon need its own time zone?

In layman’s terms, we need a reliable “lunar time” earth-syncing system because lower gravity on the moon causes time to move slightly faster there than on Earth – by just 58.7 microseconds (there are 1 million microseconds in a single second) faster within every 24 Earth hours.

This is not science fiction, even though it is a main feature of Hollywood blockbusters such as Interstellar. Known as “gravitational time dilation”, the passage of time is impacted by gravity.

Although small, these time discrepancies can cause issues with syncing satellites and space stations in lunar orbit.

An unnamed OSTP official told Reuters: “Imagine if the world wasn’t syncing their clocks to the same time – how disruptive that might be and how challenging everyday things become.”

How would we tell time on the moon?

Earth uses UTC or Coordinated Universal Time to sync time zones around the world. UTC is determined by more than 400 atomic clocks that are maintained in national “time laboratories” in about 30 countries around the world. An atomic clock uses the vibrations of atoms to achieve extreme precision in keeping track of time.

Similar atomic clocks would be placed on the moon to get an accurate time reading.

Known as Positioning, Navigation and Timing (PNT), this precision-timing system allows communications systems to measure and keep accurate timing. The Ordnance Survey, the British organisation that has been producing maps since 1791, explains that PNT has three core elements:

• Positioning – the ability to precisely determine one’s location and orientation, predominantly two dimensionally on a printed map, although three-dimensional orientation can be determined when required.
• Navigation – the ability to determine both the current and desired position (either relative or absolute), and apply corrections to course, orientation and speed to reach a desired position from anywhere in the world, from sub-surface (below the Earth’s surface) to surface, and from surface to space.
• Timing – the ability to maintain accurate and precise time from anywhere in the world.

Does NASA have plans for time zones in other parts of outer space?

Although there has been no mention of time zones on other planets, in 2019, NASA’s Deep Space Atomic Clock (DSAC) mission tested an atomic clock to improve spacecraft navigation in deep space. The DSAC mission, on SpaceX’s Falcon Heavy rocket, was launched on June 22, 2019. The rocket tested the atomic clock in Earth’s orbit for one year.

Typically, spacecraft keep accurate time by bouncing signals to atomic clocks on Earth and then the signal is sent back to the spacecraft. In this mission, the on-board atomic clock was tested to keep precise time without relying on this two-way communication between the spacecraft and the atomic clocks on Earth. The accuracy of the timing is tied to getting accurate positioning, while helping the spacecraft reach the intended location in space successfully.

As NASA’s Jet Propulsion Laboratory, the centre for robotic exploration of the solar system, explains: “A two-way system that sends a signal from Earth to a spacecraft, back to Earth and then to the spacecraft again would take an average of 40 minutes. Imagine if the GPS on your phone took 40 minutes to calculate your position. You might miss your turn or be several exits down the highway before it caught up with you. If humans travel to the Red Planet [Mars], it would be better if the system was one-way, allowing the explorers to immediately determine their current position rather than waiting for that information to come back from Earth.”

The mission successfully ended in 2021, with the on-board atomic clock maintaining the correct timing and navigational positioning.

60 Years and Counting

- the future -.

NASA’s future will continue to be a story of human exploration, technology, and science. We will go back to the Moon to learn more about what it will take to support human exploration to Mars and beyond. We will continue to nurture the development of a vibrant low-Earth orbit economy that builds on the work done to date by the International Space Station. NASA engineers will develop new technologies to improve air transport at home and meet the challenges of advanced space exploration. Our scientists will work to increase an understanding of our planet and our place in the universe. We will continue to try to answer the question, “Are we alone?”

Unlike the way the space program started, NASA will not be racing a competitor. Rather, we will build upon the community of industrial, international, and academic partnerships forged for the space station. Commercial companies will play an increasing role in the space industry: launching rockets and satellites, transporting cargo and crew, building infrastructure in low-Earth orbit. NASA will continue to be a global leader in scientific discovery, fostering opportunities to turn new knowledge into things that improve life here on Earth.

Artist’s concept, NASA’s gateway in lunar orbit. It will consist of at least a power and propulsion element as well as habitation, logistics, and airlock capabilities. The power and propulsion element will be the first component to launch for placement near the Moon in 2022, with additional elements launching in subsequent years. Image Credit: NASA

In the half-century since people visited the Moon, NASA has continued to push the boundaries of knowledge to deliver on the promise of American ingenuity and leadership in space. And NASA will continue that work by moving forward to the Moon with astronauts landing on the lunar South Pole by 2024.

NASA is implementing the President’s Space Policy Directive-1 to “lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system.” NASA stands on the verge of commercializing low-Earth orbit. These experiences and partnerships will enable NASA to go back to the Moon in 2024 – this time to stay. NASA’s backbone for deep space exploration is the biggest rocket ever built, the Space Launch System (SLS), the Orion spacecraft and the Gateway lunar command module. With its partners, NASA will use the Gateway lunar command module orbiting the Moon as a staging point for missions that allow astronauts to explore more parts of the lunar surface than ever before

Aeronautics

NASA’s work in aeronautics has made decades of contributions to aviation, national security and our economy. Ongoing research and testing of new aeronautics technologies are critical in these areas and will help the U.S. lead the world in a global aviation economy, with increasing benefits worldwide. Developing quiet supersonic transport over land, and quieter, cleaner aircraft technologies are two ways NASA is transforming aviation.

Image Credit: NASA/Chris Giersch

Quiet Supersonic Technology

Testing the Quiet Supersonic Technology (QueSST) Preliminary Design Model inside NASA Langley Research Center’s 14-by-22-foot Subsonic Tunnel. The QueSST Preliminary Design is the initial design stage of NASA’s planned Low-Boom Flight Demonstration experimental airplane, or X-plane, which aims to reduce fuel use, emissions, and noise, and to make supersonic flight over land possible.

Image Credit: NASA Graphic / NASA Langley/Advanced Concepts Lab, AMA, Inc.

Artist’s concept of NASA’s X-57 ‘Maxwell’ aircraft. The X-57 will be the first all-electric X-plane and will be flown to demonstrate the benefits that electric propulsion may yield for the future of aviation. The goal of the X-57 is to achieve a 500-percent increase in high-speed cruise efficiency, zero in-flight carbon emissions, and flight that is much quieter for the community on the ground.

Space exploration likely comes to mind when you think of NASA, but NASA’s work has many benefits that are closer to home for Earth and its citizens. Earth science research will continue, with new technologies that will help us understand Earth as a system and its responses to natural or human-induced changes. Scientists utilize satellites, airborne missions, and ground-based observations to gather data about the ongoing natural and man-made changes to Earth’s land, water, and air to help improve the quality of life around the world.

Image Credit: NASA

NASA’s best known Earth Science program will continue with the launch of Landsat 9 in 2020. Landsat 9 will extend our ability to measure changes on the global land surface at a scale where we can separate human and natural causes of change. When land use and resource availability issues arise, Landsat 9 will help decision makers make informed management decisions. Landsat 9 will thus contribute a critical component to the international strategy for monitoring the health and state of the Earth.

Artist’s concept for the Surface Water and Ocean Topography (SWOT) mission, targeted for launch 202, will make the first global survey of Earth’s surface water. SWOT will monitor how water bodies change over time and support societal needs such as dams and shipping.

Artist’s concept of one of the eight Cyclone Global Navigation Satellite System (CYGNSS) satellites deployed in space above a hurricane. CYGNSS uses GPS technology to help measure ocean winds, which will give scientists an earlier and more detailed view of a storm’s strength and direction.

When NASA was created 60 years ago, it had to invent the technology to get where we needed to go, and we will continue to push the boundaries of technology into the future. New emerging technologies that open opportunities for research and exploration with minimal investments include NASA’s small satellites. Exploring deep space and three-year missions to Mars pose new challenges: Can you take enough? Can you grow it or make it in space? Can you do your own repairs and maintenance? As before, NASA will adapt solutions to these and other challenges into technologies that will improve life at home.

Image Credit: NASA/Emmett Given

International Space Station’s 3D printer manufactures objects out of plastic. NASA is developing more advanced printers that can add metals and other materials like regolith into the mix. Being able to make parts in space will come in handy during emergencies.

NASA’s Regolith Advanced Surface Systems Operations Robot (RASSOR) excavating simulated extraterrestrial soils. NASA is developing technologies to drill into regolith (space word for “soil”) on the Moon, Mars, and asteroids and to convert it into oxygen, drinkable water, other products to support human and plant life, consumables, and fuel sources.

Communicating from Earth to any spacecraft is a complex challenge, largely due to the extreme distances involved. When data are transmitted and received across thousands, millions, and even billions of miles, the delay and potential for disruption or data loss is significant. Advanced communication technologies are essential to enhance deep space exploration for both robotic and human missions. Delay/Disruption Tolerant Networking (DTN) is NASA’s solution to reliable internetworking for space missions. DTN will enable a Solar System Internet with automated data delivery between users no matter how distant and intermittent their connections may be.

Technicians test a flight modem in a thermal vacuum chamber for NASA’s Laser Communications Relay Demonstration (LRCD) mission. The modems encode data into laser light to be transmitted to the ground from a satellite orbiting at the same speed Earth is turning. Optical communications technologies can dramatically improve communications between spacecraft and Earth—10 to 100 times better than radio communications’ data rates.

The Deep Space Optical Communications (DSOC) package aboard NASA’s Psyche will use a light or laser communications to transmit more data to Earth in a given amount of time. The DSOC seeks to increase spacecraft communications performance and efficiency without increasing the mission burden in mass, volume, power and/or spectrum.

Human Spaceflight

Nearly a half-century ago, Apollo 11 astronaut Neil Armstrong walked on the Moon. NASA is now preparing for an ambitious new era of sustainable human spaceflight and discovery. The agency is building the Space Launch System rocket and the Orion spacecraft for human deep space exploration. With the help of commercial and international partners, NASA will develop new opportunities in lunar orbit, including a platform to aid surface exploration and serve as a gateway to Mars. The International Space Station will continue to serve as the world’s leading laboratory where researchers can conduct cutting-edge research and technology development to enable human and robotic exploration of the Moon and Mars. The space station will also facilitate the growth of additional privately owned spaceships for continued research and transportation in low-Earth orbit.

The Bigelow Expandable Activity Module (BEAM), constructed by Bigelow Aerospace, attached to the International Space Station’s Tranquility module to test the technology. Lightweight expandable or “inflatable” habitats require much less transport volume for potential future space missions. The modules expand after being deployed in space, providing a comfortable area for astronauts to live and work.

Image Credit: NASA/Rad Sinyak

Orion Spacecraft

Testing for the new Orion spacecraft. In a lab at NASA’s Johnson Space Center in Houston, engineers simulated conditions that astronauts in space suits would experience when the new Orion spacecraft is vibrating during launch atop the agency’s powerful Space Launch System rocket on its way to deep space destinations.

Image Credit: Sierra Nevada Corp

Dream Chaser

Sierra Nevada Corporation’s Dream Chaser cargo spacecraft will join NASA’s commercial cargo providers Orbital ATK and SpaceX to deliver research and supplies to the International Space Station. The Dream Chaser also will be able to bring research back to Earth, and Sierra Nevada Corporation also is developing a crew version of the spacecraft for commercial use.

NASA's Space Launch System will be 364 feet tall in the crew configuration and will have a 115-ton lift capacity. Image Credit: Sierra Nevada Corp

Space Launch System

NASA’s Space Launch System, or SLS, is a powerful, advanced launch vehicle. With its unprecedented power and capabilities, SLS will launch crews of up to four astronauts in the agency’s Orion spacecraft on missions to explore multiple, deep-space destinations. Offering more payload mass, volume capability and energy to speed missions through space than any current launch vehicle, SLS is designed to be flexible and evolvable and will open new possibilities for payloads, including robotic scientific missions to places like Mars, Saturn and Jupiter.

James Webb Space Telescope

The James Webb Space Telescope, a NASA-led project in collaboration with the European and Canadian space agencies, will be world’s next premier space science observatory. Webb will solve mysteries of our solar system, look beyond to distant worlds around other stars, and probe the mystifying structures and origins of our universe. Webb will study every phase in the history of our universe, ranging from the first luminous glows after the Big Bang to the formation of solar systems and the evolution of our own solar system. Webb will open up new windows to study the atmospheres of planets around other stars and how it relates to exoplanet systems.

Parker Solar Probe

NASA’s Parker Solar Probe will be the first-ever mission to "touch" the Sun. The spacecraft, about the size of a small car, will travel directly into the Sun's atmosphere about 4 million miles from our star's surface.

Solar System

NASA will be returning to places previously explored with ambitious new missions and new technologies. Much remains to be learned about the Moon and how we might use its soils and other resources to support human habitation elsewhere. The complex journey to Mars is challenging NASA and its partners to figure out how to get there, land there, live there and get home. NASA will also be searching for clues of life throughout our solar system.

Mars 2020 Rover

NASA’s Mars 2020 Rover will be instrumental to NASA’s Mars Exploration Program, which seeks to determine whether life ever arose on Mars, to characterize the climate and geology of the Red Planet, and to prepare for human exploration.

Europa Clipper

NASA's Europa Clipper will conduct detailed reconnaissance of Jupiter's moon Europa and investigate whether the icy moon could harbor conditions suitable for life beneath its icy crust.

Does space travel make people age more slowly?

• 2 min. read ▪ Published February 22, 2021
• Share on LinkedIn
• Share on Facebook
• Share on X (Twitter)

Scientists have recently observed for the first time that, on an epigenetic level, astronauts age more slowly during long-term simulated space travel than they would have if their feet had been planted on Planet Earth.

“Many of us assume that being exposed to radiation or other harm in space would be reflected by increased aging. But there’s also been a lot of research that has shown the opposite,” said Jamaji C. Nawanaji-Enwerem, Berkeley Public Health postdoctoral fellow and first author of a study published in Cell Reports in November 2020. The study reviewed data from the six participants of the Mars-500 mission, a simulated space travel and residence experiment launched by the European Space Agency in 2010.

In space, people usually experience environmental stressors like microgravity, cosmic radiation, and social isolation, which can all impact aging. Studies on long-term space travel often measure aging biomarkers such as telomere length and heartbeat rates, not epigenetic aging. To fill in the gap, Nawanaji-Enwerem and his team members took the novel step to look at epigenetic biomarkers such as DNAmPhenoAge, a robust marker of disease risk, and DNAmGrimAGE, a predictor of mortality risk.

The findings show that space mission duration will lead to a slower aging process, which looks like a good thing. “But if the mission goes on for longer, it can actually be a bad thing for you,” said Nawanaji-Enwerem.

“It also informs future research in terms of what biomarkers of aging are important to measure,” said Andres Cardenas, study co-author and assistant professor of Environmental Health Sciences at Berkeley Public Health.

During the Mars-500 experiment, six astronaut crews stayed in an isolated space and lived as if they were on Mars for 520 days. Cosmic radiation and microgravity were not replicated in the experiment, so the slower aging process found by scientists is caused by social isolation and other relative effects.

Although it’s not clear why space travel would lead to slower epigenetic aging, the findings will be valuable for understanding the health implications for future space travel.

“It’s not if, but when, we’re going to transition to space living,” said Cardenas.

More in category “Research Highlights”:

Surgery in a hospital doesn’t necessarily lead to better outcomes than surgery in a surgical center, collaboration is key to pioneering research with youth experiencing homelessness, exposure to wildfire smoke during pregnancy increases risk of preterm birth, rosemarie de la rosa tracks how childhood exposure to environmental pollutants and social stress has lifelong affect.

20 Years On, How the Columbia Shuttle Disaster Changed Space Travel

F olks around NASA don’t much care for this time of year. It was 56 years ago last week—January 27, 1967—that astronauts Gus Grissom, Ed White, and Roger Chaffee lost their lives in a launch pad fire inside their Apollo 1 spacecraft as they were running a dress rehearsal for countdown. It was 37 years ago—on January 28, 1986—that the shuttle Challenger exploded during launch due to a faulty seal that caused one of the solid rocket boosters to ignite the external fuel tank. The pair of solid boosters flew on heedlessly, leaving a gruesome, two fingered fireball in the sky as seven astronauts perished, including New Hampshire school teacher Christa McAuliffe.

Seventeen years later, on January 28, 2003, astronaut Rick Husband, commander of the shuttle Columbia, which was then in orbit, marked the anniversaries. “They made the ultimate sacrifice,” he said, “giving their lives for their country and mankind. Their dedication was an inspiration to each of us.”

America would have to find a similar kind of grim inspiration just four days later, when, on February 1—20 years ago today—Columbia met an end similar to Challenger’s, breaking apart during reentry, when hot plasma tore through the spacecraft from a breach in the leading edge of the left wing. Husband and his crew of six were killed, as the shuttle, on its way to a landing at the Kennedy Space Center in Florida, left a debris trail that stretched from eastern Texas to Louisiana.

“A poisonous rain of broken shuttle pieces fell onto backyards and roadsides and parking lots, through the roof of a dentist’s office, bits of machinery in Nacogdoches, a hand and leg in San Augustine,” wrote TIME’s Nancy Gibbs , as part of the magazine’s cover package that week.

Then-President George W. Bush scheduled a call with the family members of the lost crew for later that day and spent part of his morning studying crew biographies to see which astronauts had spouses and children.

“Tough day, tough day,” was all Bush could mutter to himself as he prepared to place the call.

It was that, indeed. NASA reacted as NASA does in such circumstances, first with a certain minimalism and stoicism. As I reported in a piece that accompanied Nancy’s: “‘A space-shuttle contingency has been declared,’ the voice of Mission Control intoned in the arid argot of the space agency. It was an echo of the understated announcement 17 years ago, when the shuttle Challenger consumed itself in an awful fireball, and the stunned NASA narrator was left to declare, ‘Obviously a major malfunction.’”

But NASA has done other things too when faced with tragedy. It has searched for the cause of the problem and fixed it. In the case of the Apollo 1 fire, that meant redesigning the spacecraft from top to bottom to avoid the kind of errant spark that set off the blaze, as well as replacing the cockpit’s pure-oxygen atmosphere—which burns like gasoline—with an oxygen-nitrogen mix when the spacecraft was at high internal pressure on the ground. (In space, where the internal pressure is much lower due to the vacuum outside, the spacecraft could safely be filled with pure oxygen.) NASA also changed all of the fabric in the spacecraft, including the astronauts’ suits, to a burn-resistant beta cloth. In the case of Challenger, fixing what went wrong meant redesigning the solid fuel boosters and changing the launch rules, to prevent a liftoff in the uncharacteristic Florida freeze that January morning that had left the engine seals brittle.

In the case of Columbia, the job meant first pinpointing the cause of the breach in the shuttle that allowed the hot plasma to infiltrate the spacecraft. It was ultimately traced via liftoff footage to a suitcase-sized piece of hard insulating foam that fell off the external tank and struck the wing in the first moments of the spacecraft’s flight. That meant doing away with the insulating foam at the spot where the tank joins the shuttle—the region from which the deadly fragment fell—and replacing it with heaters. It also meant that on future flights to the International Space Station, shuttle pilots would do a sort of pirouette of their vehicle so that station astronauts could give it a visual inspection. NASA also kept another shuttle at the ready in case a mission had to be launched to rescue a crew aboard a ship that could not reenter safely.

But both Columbia and Challenger led to another kind of change too—a sort of back to the future reversal in spacecraft design. The rocketry revolution that the shuttle program sought to herald was intended to be the end of the old model of putting humans at the top of a booster, firing them into space, and throwing away the launch vehicle after a single use. The new shuttle would be reusable, with the spacecraft itself gliding gracefully back to Earth, the spent solid boosters dropping by parachute into the ocean and being recovered, and only the external tank—little more than a huge shell of metal and plumbing—being discarded.

But there was a lifesaving advantage in the old design that NASA was eschewing with the shuttles: that business of the crew being perched atop the pyrotechnics. Ever since the days of NASA’s first crewed flights, spacecraft-and-booster stacks were designed so that sensors would detect any impending problem in the rocket and either blast the crew-carrying capsule away from it by escape engines or, in the case of the 1960s’ two-man Gemini program, signal the commander to pull a D-shaped ring that would activate parachute-equipped ejection seats.

In the newer shuttle design, the crew was placed directly next to the pyrotechnics. Challenger’s tank explosion happened with the shuttle riding atop it like a human on a horse. Columbia’s wing could never have been damaged if it hadn’t been located below the spot on the tank from which foam fell. Even before the remaining three shuttles were retired in 2011, NASA vowed that in the future it would keep fuel and humans separate, returning to the old model of crew riding at the top of the missile—a model adopted by NASA’s new moon rocket, the Space Launch System ; SpaceX’s Falcon 9 and Starship rockets; and Boeing’s crew-carrying Starliner spacecraft . And in the case of SpaceX, most of the throwaway problem has been addressed, with the first stage of the Falcon 9, and both stages of the planned Starship rocket returning for upright landings, allowing them to be used again.

Now, two decades on from the most recent loss, and generations removed from the earlier ones, NASA does not let the memories of the missing men and women—or the sacrifice they made—fade. Each year, on the last Thursday of January, the space agency holds a NASA Day of Remembrance to celebrate their lives—and mourn their loss. We take space travel as a fixed fact of 20th and 21st century life. But crews take a big gamble—on physics, fate, and engineering—when they climb aboard a spacecraft. We all benefit from the fact that they do—and all are made poorer, more sorrowing, by the mercifully few times that gamble does not pay off.

More Must-Reads From TIME

• The 100 Most Influential People of 2024
• How Far Trump Would Go
• Why Maternity Care Is Underpaid
• Scenes From Pro-Palestinian Encampments Across U.S. Universities
• Saving Seconds Is Better Than Hours
• Why Your Breakfast Should Start with a Vegetable
• Welcome to the Golden Age of Ryan Gosling
• Want Weekly Recs on What to Watch, Read, and More? Sign Up for Worth Your Time

Write to Jeffrey Kluger at [email protected]

Russian cosmonaut Yuri Gagarin, the first man in space, completed a circuit of the Earth in the spaceship Vostok 1 on April 12, 1961.

5 Changes in Space Travel Since Yuri Gagarin's Flight

On Yuri's Night, space historians reflect on how far technologies have advanced.

A little over 50 years ago, no one on Earth knew what would happen when a human being was launched into space. That all changed on this day in 1961, when Yuri Gagarin , a Soviet military pilot and cosmonaut , hurtled into orbit aboard Vostok 1.

He circled the Earth once, reporting that he was feeling "excellent" and could see "rivers and folds in the terrain" and different kinds of clouds. "Beautiful" was his simple description of the view. Weightlessness, he said, felt "pleasant." (See pictures of Gagarin's flight .)

In the decades since Gagarin became the first person in space, what began as a politically fraught competition has yielded men on the moon, space walks, and visions of putting people on Mars . Here's a look at some of the important changes in space travel that occurred along the way.

Gagarin's flight represented a triumph for the Soviet Union during the heat of the Cold War, from which both the U.S. and Russian space programs were born. "The space race was partly about impressing the living daylights out of other nations because the science and technology are closely aligned with military capability," says Roger Launius, senior curator and space historian at the Smithsonian's National Air and Space Museum .

The Soviets, notes Launius, kept secret for years the fact that Gagarin had to bail out of his spacecraft with a parachute several miles above ground during the landing. The spherical Vostok capsule lacked thrusters to slow it down, and requiring Gagarin to eject before reaching the ground might have meant the mission didn't qualify as the first successful human space flight. "They had no idea what was going to happen—the capsule could have left a big hole in the ground," Launius says. (See pictures of space suit evolution .)

Nowadays the U.S. and Russia collaborate regularly, with cross-training and joint flights to the International Space Station (ISS). The launch pad from which Gagarin took off—Baikonur Cosmodrome in what is now Kazakhstan—is still used today, most recently to send two cosmonauts and a U.S. astronaut to the ISS in March.

Escaping Earth

Gagarin's mission required a rocket that could propel his spacecraft fast enough to sustain a speed of some 17,000 miles per hour (27,359 kilometers an hour), known as orbital velocity. Less than a decade later, NASA's Saturn V rocket achieved escape velocity—the speed required to escape Earth's gravitational pull (25,039 miles per hour or 40,320 kilometers per hour). This milestone made it possible to put men on the moon.

Saturn V stood taller than the Statue of Liberty and generated more power than 85 Hoover Dams. It was a thing of beauty, and resulted in the first human footsteps on extraterrestrial terrain, when Neil Armstrong stepped onto the moon in 1969. More Apollo missions followed, and Saturn V took its final bow in 1973, when it launched the Skylab space station into orbit.

Creature Comforts

Gagarin traveled in what was essentially a giant ball and didn't have the capacity to control his spacecraft. If he were to take a tour of the International Space Station today, he might be impressed with the amenities: exercise bikes, barbeque beef brisket—even a choice of toilet papers.

"There wasn't a lot of interest early on in making cosmonauts comfortable—they were there to do a task," says Launius. "It's only with longer-term missions that you have to worry about comfort."

Hence the memorable shower aboard Skylab , NASA's space station during the 1970's and first attempt to test the ability of humans to work and live in space for extended periods. The weight of water and the large equipment required to recycle it, however, proved too much of a burden, says NASA spokesman Jay Bolden, leaving today's space dwellers resorting to "basic squirts of water and soap on washcloths for sponge baths."

Space Medicine

Gagarin's mission lasted 108 minutes, so he didn't have to eat. But the cosmonaut who followed him into space, German Titov, went up for more than a day. People wondered: Would he be able to swallow food?

Today's big questions about space travel and the human body involve bone loss and radiation exposure, but fundamental questions existed even then, notes NASA's chief historian Bill Barry. "People asked if you could swallow without gravity. One of Titov's experiments was to eat something in space," he says.

Another mystery was "space sickness," involving severe nausea. Titov suffered a bad case of it, which worried the Soviets greatly, says Barry. Now it's known to be common among space travelers and even bears a medical name: space adaptation syndrome.

Modern studies focus on the effects of long-term space travel, as eyes turn to Mars and people spend months—even longer than a year in the case of cosmonaut Valeri Polyakov—working in space. "In less than a week we see signs of degradation in the human body," says Launius of the Smithsonian. "I would contend that the real challenge for space travel is biomedical, not technological."

Commercialization

Perhaps the most remarkable change in space travel since Gagarin's historic flight is how routine it's become—and possible for the right price.

Millions of dollars have landed private citizens a seat on Russian spacecraft, though Russia halted its space-tourism role in 2010. (It cited the need to devote its Soyuz capsules to ferrying ISS crew members after NASA ended its space-shuttle program.) Still, so-called space tourism remains on the map as companies like Virgin Galactic race to launch suborbital flights that skirt the edge of space and offer a taste of weightlessness. Virgin's ticket price: $200,000.

"Not all commercial space activities are about tourism," notes Launius. "Many are about communication, remote sensing, or other activities in which a profit may be made."

One thing that hasn't changed is the view from above. People may no longer stop to take in the video feed from spacecraft floating above Earth, but just listen to Gagarin's conversation with his ground control and you can feel the suspense and awe of seeing the planet from space.

No wonder a great window counts as a major creature comfort for the ISS crew. "The astronauts love to hang out in the station's cupola ," with its panoramic views of Earth, says Barry. "I hear they moved an exercise bike there, and one guy likes to hang out and play his guitar."

Related Topics

• SPACE EXPLORATION

You May Also Like

Second SpaceX megarocket launch ends with another explosion. What happens next?

How to plan a weekend in County Wicklow, the beautiful 'Garden of Ireland'

See Sally Ride’s boundary-breaking life in photos

The moon’s darkest corners are a mystery. This image offers a stunning new glimpse.

NASA has a plan to clean up space junk—but is going green enough?

Moriba Jah is paving the way for sustainable space exploration

Did Pluto ever actually stop being a planet? Experts debate.

• Environment

History & Culture

• History & Culture
• History Magazine
• Mind, Body, Wonder
• Coronavirus Coverage
• Paid Content
• Terms of Use
• Privacy Policy
• Your US State Privacy Rights
• Children's Online Privacy Policy
• Interest-Based Ads
• About Nielsen Measurement
• Do Not Sell or Share My Personal Information
• Nat Geo Home
• Attend a Live Event
• Book a Trip
• Inspire Your Kids
• Shop Nat Geo
• Visit the D.C. Museum
• Learn About Our Impact
• Support Our Mission
• Advertise With Us
• Customer Service
• Renew Subscription
• Manage Your Subscription
• Work at Nat Geo
• Sign Up for Our Newsletters
• Contribute to Protect the Planet

Copyright © 1996-2015 National Geographic Society Copyright © 2015-2024 National Geographic Partners, LLC. All rights reserved

What Is Time Dilation And What Will It Do To Astronauts Who Want To Travel To Mars?

T here is probably an unbelievably long list of the challenges that human astronauts would face in the event of a manned mission to Mars.

Dealing with time dilation is definitely on the list.

We all experience time dilation to some degree. Time passes at different rates for different observers, depending on their relative speeds and their proximity to (and strength of) nearby gravitational fields.

Your head and your feet technically experience time differently, making your head slightly older than your toes.

Weird, right?

Time dilation is the difference between time elapsed on two clocks depending on their special relativity and general relativity.

Because of the way gravity curves spacetime, gravity is stronger near you, and the closer you move to the mass creating gravity, the slower time moves.

The further you get away from Earth’s gravity – like, if you’re on top of a tall building – the more pronounced the effect compared to those on the ground.

Not a lot in that example; a fraction of a nanosecond a year.

It is much more pronounced for astronauts experiencing zero-gravity for long periods of time.

That said, astronomer Colin Stuart says it’s almost canceled out by the speed at which they travel through space.

“Because astronauts and satellites orbiting the Earth are slightly further away from the centre of the planet (compared to people on the ground) they actually experience less gravitational time dilation. O its own this would mean astronauts’ time would run faster. However, this effect is quite small because Earth’s gravity is quite weak and so the time dilation due to their speed wins out and astronauts really do travel a tiny amount into the future.”

When Cosmonaut Sergei Krikalev was stranded in space for 311 days, he technically traveled 0.02 seconds into the future.

A trip to Mars would take around 21 months, roundtrip. The astronauts will experience time passing normally, but it will actually be a few nanoseconds difference from how we experience life on Earth.

If they stayed on Mars for extended periods of time, the effects of gravitational time dilation could be enough to be noticeable.

For example, if you lived 80 years on Mars, you would pass away 12 seconds earlier than if you passed away after exactly 80 years on Earth.

From the point-of-view of the person experiencing either end, though, it would feel exactly the same.

Spacetime is wild, y’all.

I have a feeling we’re going to have the opportunity to study it more in depth very soon.

Sign Up to receive the Twisted Sifters weekly newsletter for the best Internet culture news updates.

The post What Is Time Dilation And What Will It Do To Astronauts Who Want To Travel To Mars? first on TwistedSifter .

History of Space Travel

Learn about the history of humans traveling into space.

The first earthling to orbit our planet was just two years old, plucked from the streets of Moscow barely more than a week before her historic launch. Her name was Laika. She was a terrier mutt and by all accounts a good dog. Her 1957 flight paved the way for space exploration back when scientists didn’t know if spaceflight was lethal for living things.

Humans are explorers. Since before the dawn of civilization, we’ve been lured over the horizon to find food or more space, to make a profit, or just to see what’s beyond those trees or mountains or oceans. Our ability to explore reached new heights—literally—in the last hundred years. Airplanes shortened distances, simplified travel, and showed us Earth from a new perspective. By the middle of the last century, we aimed even higher.

Our first steps into space began as a race between the United States and the former Soviet Union, rivals in a global struggle for power. Laika was followed into orbit four years later by the first human, Soviet Cosmonaut Yuri A. Gagarin. With Earth orbit achieved, we turned our sights on the moon. The United States landed two astronauts on its stark surface in 1969, and five more manned missions followed. The U.S.’s National Aeronautics and Space Administration (NASA) launched probes to study the solar system. Manned space stations began glittering in the sky. NASA developed reusable spacecraft—space shuttle orbiters—to ferry astronauts and satellites to orbit. Space-travel technology had advanced light-years in just three decades. Gagarin had to parachute from his spaceship after reentry from orbit. The space shuttle leaves orbit at 16,465 miles an hour (26,498 kilometers an hour) and glides to a stop on a runway without using an engine.

Space travel is nothing like in the movies. Getting from A to B requires complex calculations involving inertia and gravity—literally, rocket science—to "slingshot" from planet to planet (or moon) across the solar system. The Voyager mission of the 1970s took advantage of a rare alignment of Jupiter, Saturn, Uranus, and Neptune to shave off nearly 20 years of travel time. Space is also dangerous. More than 20 astronauts have died doing their job.

That hasn’t stopped people from signing up and blasting off. NASA’s shuttle program has ended, but private companies are readying their own space programs. A company called Planetary Resources plans to send robot astronauts to the Asteroid Belt to mine for precious metals. Another company named SpaceX is hoping to land civilian astronauts on Mars—the next human step into the solar system—in 20 years. NASA and other civilian companies are planning their own Mars missions. Maybe you’ll be a member of one? Don’t forget to bring your dog.

Space videos

Outer this world, planet earth, calling all earthlings, the milky way, shoot for the stars, what is hubble, how hubble works, read this next, total solar eclipse.

• African American Heroes

Katherine Johnson

• Action and Adventure

Space Explorer

• Terms of Use
• Privacy Policy
• Your California Privacy Rights
• Children's Online Privacy Policy
• Interest-Based Ads
• About Nielsen Measurement
• Do Not Sell My Info
• National Geographic
• National Geographic Education
• Shop Nat Geo
• Customer Service
• Manage Your Subscription

Copyright © 1996-2015 National Geographic Society Copyright © 2015-2024 National Geographic Partners, LLC. All rights reserved

• International edition
• Australia edition
• Europe edition

‘We’re in a new era’: the 21st-century space race takes off

As humans enter what has been termed the ‘third space age’, it’s private companies – not governments – leading the charge

I f the 20th-century space race was about political power, this century’s will be about money. But for those who dream of sending humans back to the moon and possibly Mars, it’s an exciting time to be alive whether it’s presidents or billionaires paying the fare.

Space flight is having a renaissance moment, bringing a fresh energy not seen since the days of the Apollo programme and, for the first time, with private companies rather than governments leading the charge.

A series of recent milestone missions, not least the increasingly successful test flights of the largest rocket ever made and the first privately built probe to land on the lunar surface , have embedded a growing idea that humans are entering what has been termed the “third space age”.

“To say we’re in a new era, that’s absolutely fair,” said Greg Sadlier, a space economist and the co-founder of the know.space consultancy. “We’re in the era of competition, or the commercial era. The barriers to entry are lower, the costs have fallen, which has opened the doors to a much larger pool of nations,” he said. “It’s the democratisation of space, if you like.”

Today, more than 70 countries have space programmes, but for a long time, the US and the Soviet Union were the only big players.

Humanity’s first space explorer, the Soviet cosmonaut Yuri Gagarin, orbited around the globe in April 1961. A year later, US President John F Kennedy gave his famous “we choose to go to the moon” speech, promising to get an American man on the lunar surface by the end of the decade ahead of a “hostile flag of conquest”.

“To be sure, all this costs us all a good deal of money,” Kennedy acknowledged, but the cold war motivated him to spend the modern-day equivalent of hundreds of billions in US taxpayers’ money to win the space race.

The end of the cold war in 1989 brought a brief moment of global optimism, leading to the second, more collaborative space age. The International Space Station was assembled over 13 years and, since 2000, people of multiple nationalities have been living in space constantly, working together on experiments in the orbiting laboratory.

However, this second era also saw a dip in efforts to get humans farther out into space, symbolised by Nasa’s space shuttle programme that never sent people beyond Earth’s orbit and was eventually disbanded in 2011, in large part because the US government did not want to keep bankrolling its high costs. Afterwards, Washington had to rely on Moscow’s Soyuz rockets to get its astronauts into space.

Yet those high costs have now been driven down by private businesses entering the scene, often as government contractors. In the past few years, some of these businesses have started to make money, although not from headline-grabbing reasons such as space tourism but mostly for sending up communication satellites, especially broadband internet. Many estimates suggest the global space industry could generate revenues of more than $1tn within the next two decades.

In an article published last year by the influential strategy and management consultancy McKinsey & Company, global managing partner Bob Sternfels and his colleagues wrote to CEOs: “If space isn’t part of your strategy, it needs to be.”

They added: “Only recently have we seen significant acceleration down the cost curve: launch costs have fallen 95% (with another massive reduction expected in the coming years) thanks to reuse, improved engineering, and increased volumes.”

Elon Musk’s SpaceX has been at the forefront of this movement, launching 96 times last year with its reusable rockets. The company’s largest system, called Starship and still in development, has been marketed as an interplanetary explorer. Musk says he built the 120-metre rocket so that humans can colonise Mars. Before then, Nasa has contracted SpaceX to land astronauts, including the first woman, on the moon this decade.

As a business venture, it could make money well before then by serving as the equivalent of a flying cargo ship. Starship has a payload of up to 150 metric tonnes, five times the load the space shuttle could carry.

Global politics continues to play a role in space but with more players. China has overtaken Russia as the main national contender to the US, with its own space station in operation, probes on the moon and a rover on Mars. On Friday, Beijing is due to launch a robotic spacecraft to the moon’s far side.

The moon’s south pole, in particular, is seen as a “golden belt” for lunar exploration as it contains water ice, which could be used as drinking water and even broken down to make rocket fuel.

Scientists are nervous about both the politicisation and the commercialisation of space, especially with talk of future “mining” operations on the pristine, untouched moon. Advocates of space exploration, however, point to advancements made so far. The CT scan, a critical medical device that can identify tumours, traces its origins to pre-Apollo mission research; astronauts on the space station have been using the unique microgravity environment to better understand diseases such as Alzheimer’s .

For economists like Sadlier, the third space age creates an unprecedented situation – one that could upend the very foundations of the market system. “In economics, we assume that resources are limited; land is limited; natural resources are limited,” he said. “With space, it allows us to change that.”

• International Space Station

Most viewed

Den of Geek

The Movies That Confronted the Scariest Challenges of Space Travel

Hollywood must be afraid of Einstein considering how few movies seriously address the theory of relativity. Here are the ones who actually face the cold truth about space travel.

• Share on Facebook (opens in a new tab)
• Share on Twitter (opens in a new tab)
• Share on Linkedin (opens in a new tab)
• Share on email (opens in a new tab)

Space is great. It’s massive, it’s colorful, and you can have big fights with lasers there. It really does have everything you could want. But it also has problems—mainly, like we said, that it’s massive. In fact it’s so massive that if you want to go anywhere in it (apart from a few nearby planets with hardly anyone to shoot lasers at), by the time you get there, you’re dead. Now you might think that if you can just go fast enough, you’ll get there before you die, but there’s a problem.

That problem, as Albert Einstein tells us, is the speed of light. Light, in a vacuum, travels at just short of 300 million meters per second, fast enough to get from Earth to the moon in a little over a second. The thing is if you’re chasing a light beam, and travel behind it at 150 million meters per second, if you clock the light beam’s speed you’ll see it racing away from you at just under 300 million meters per second. But at the same time, an observer watching both of you will see the light beam move away from them at 300 million meters a second. The speed of light remains the same for both of you, but for that to be true, time has to be moving differently.

This has two important consequences. First, you are never going to be as fast as a beam of light. The second is that the closer you get to the speed of light, the more slowly time will pass to compensate.

Most movies get around this massive conundrum with hyperspace, warp drive, quantum jump technology, the improbability drive, or iso-hexagonic dimensional skipping. Alternatively, to keep your hard-sci-fi credentials, your astronauts might simply nap through the years of travel between the stars. But a small number (a really quite surprisingly small number) of films have dared to face Einstein head-on and reap the consequences of approaching the universe’s ultimate speed limit. Here’s how they addressed space travel’s most menacing challenge.

Ad – content continues below

Planet of the Apes (1968)

Perhaps the first film to take on relativistic space travel was Planet of the Apes —although credit is not given to Einstein, but to “Dr. Haslein’s theory of time.” At the very opening of the film, Charlton Heston’s character tells us that, with the speed their spacecraft travels at, time will pass more slowly for the human astronauts than it will for people back on Earth. This sets up the twist that the alien planet they land on—where three recognizable species of ape, as well as homo sapiens, speak the Queen’s English—is in fact Earth in the distant future.

It also demonstrates one of the reasons why relativistic movie space travel is so rare. Travel at 99.9999999 percent of the speed of light is at least theoretically possible, and would reduce travel between the stars in our own neighborhood to the timeframes of sail-powered ocean voyages rather than the rise and fall of civilizations. But it can look like a hat on a hat. Suddenly your space travel story is now also a time travel story. And not a fun one, like where you go back in time and save some humpback whales; it’s a sad one where the people you know age and die in moments and the world you left behind changes beyond all recognition by the time you return to it.

Dark Star (1974)

Directed by John Carpenter and written by Alien ’s Dan O’Bannon, this film doesn’t hinge any great plot twists on its time dilation. It is merely mentioned that the crew have aged only three years during their 20-year mission of rogue planet extermination. It takes the negatives of using relativity in space travel and turns them into a positive. The time dilation becomes simply another twist of the knife of isolation and dehumanisation that permeates the film. Not only are these characters removed from their families and homes to do a trivial yet dangerous job for an employer that doesn’t care for them, but those families and homes will be irreparably changed when they do see them again.

Many regard Dark Star as a prototype for Alien . The film even has its own alien lifeform running around the ship, albeit that alien looks like a beach ball with feet. And Alien is an interesting case study of Hollywood’s discomfort around the passage of time during space travel. That film sees its crew start the film waking up from hypersleep. The implication is straightforward—these are low-paid, low-valued workers whose employer thinks nothing of tossing them into space for years at a time travelling at sublight speeds.

But in Aliens , particularly the director’s cut, we learn that Ripley went on this mission expecting to be home by her daughter’s 11th birthday—not a promise you can make with any interstellar travel that doesn’t F the TL. Hollywood gets really uncomfortable with any implication that future technology might change the way people, particularly families, relate to one another, even though that is something that has habitually changed on the regular throughout human history.

Flight of the Navigator (1986) 

Flight of the Navigator is all about family relationships changing as a result of relativistic space travel. One of the more successful films to attempt to ride E.T. ’s coattails (at this point we all side-eye 1988’s Mac and Me and collectively shudder), Flight of the Navigator sees a young David Freeman abducted by an alien probe and returned years later with no time having passed. Suddenly all his school friends are 20 years old, his little brother is his big brother, his parents have spent eight years grieving for the son they had probably assumed was gruesomely murdered, and pop music is just noise, and boys on telly are wearing makeup.

So once again we are using space travel to fuel a time travel story, and a road movie as David and the alien robot Max fly across America, learning about humanity and friendship. But ultimately, to deliver the happy ending Hollywood demands, Flight of the Navigator has to fudge the science. It is not enough to allow David to adapt to the new time and family he has found himself in. The status quo must be restored, and for that to happen Max must fly David through some scary lightning effects to drop him off back in time at the precise moment he left.

Get the best of Den of Geek delivered right to your inbox!

This will be the first of many such fudges.

Interstellar (2014)  

Christopher Nolan ’s space exploration flick is probably the most famous take on time dilation . It is, it has to be said, a film that has done its homework. Although it uses a wormhole to get our astronauts into outer space, a combination of speed and veering too close to serious gravity wells means that decades pass at home while only a short time passes on board the ship. As well as portraying some of the realities of time dilation, this movie also gave us our most scientifically accurate visualization yet of a black hole.

It also, admirably, does not insist on a magic backward-time-travel fudge to restore a familial status quo at the end. The film ends with Matthew McConaughey reunited with his daughter, who is now an old lady, and there is no question of magically reversing that to let him watch her grow up. But even here, the scientifically accurate black hole allows Matthew McConaughey to send a message backward in time to his daughter’s childhood because of the cosmic power of love, or something, making the entire plot into a bootstrap paradox.

Lightyear (2022)

Despite being a Pixar movie intended to be an imaginary movie that a toy is based on in another Pixar movie , Lightyear gives us a surprisingly realistic take on time dilation at extreme speeds. In this film, Buzz Lightyear is part of a crew forced to build a colony when their ship is stranded on a hostile alien planet. Buzz is used as a test pilot to perfect an engine that could allow the colonists to return home, but because he’s moving at relativistic speeds, each trip to the local star and back sends him months, years and eventually decades forward in time.

If you’re waiting for the fudge, you might be pleasantly surprised to learn that this time Buzz doesn’t find a way to go back in time and put everything back to normal. No, instead his evil alternate timeline twin does that, forcing Buzz to fight evil elderly alternate future Buzz (Zerg’s real identity). But can you make a great movie that acknowledges the crunchy realities of relativity without upsetting scientists with hand-wavy backward time travel? Well, not yet. But people are trying.

The Forever War (TBA)

Probably the best story to handle space travel at relativistic speeds is Joe Haldeman’s The Forever War . Written partially in response to the jingoistic (and a little fascist) Starship Troopers , the novel uses relativistic time dilation as a fantastic metaphor for troops returning home during the Vietnam War. It uses time dilation to portray the feeling of returning home from combat to discover the wide social changes that have taken place at home, but with plenty of space wars. In short, it is perfect movie fodder.

The film rights to the book have been changing hands since 1988. For a long time, Ridley Scott was set to direct with plans to make it a 3D spectacle to rival Avatar (which also featured space travel subject to time dilation, but you would have to read a lot of behind-the-scenes material to find that out). However, in 2015 the rights expired and were quickly bought up by Warner Bros. with the intent to make it a Channing Tatum vehicle. The film is supposedly still in development, but just like on a spaceship moving at close to the speed of light, time moves slowly in development hell.

And the Honorable Mentions

At time of writing MGM have just announced a release date for their adaptation of Project Hail Mary , an extrapolation of a novel by The Martian author Andy Weir, with Phil Lord and Chris Miller sitting in the (double-seated) directors’ chair. The film, starring Ryan Gosling, attempts to offer a hard sci-fi take on an astronaut travelling to a nearby star to find the source of a mysterious space-borne lifeform that is causing our sun to dim.

Unlike The Forever War , time dilation doesn’t make up a huge part of the story other than emphasizing how isolated the hero is, but it is still mentioned in the book and forms a crucial plot point.

Outside of movies, a band of developers who previously worked on the Mass Effect games have now announced the action RPG, Exodus , a seemingly hard-sci-fi take on the space opera where the player will endure time dilation as they travel from system to system while epochs pass behind them. But after a lot of searching, we have found precisely five completed films that make use of time dilation, three of which fudge the science (If you know of any others, please let us know in the comments. This isn’t an attempt to drive engagement, I just want to watch those movies!).

Of course a lot of space travel stories still reach straight for the hyperdrive, but by embracing space travel, you not only open up opportunities to let people see far beyond their years, and show off the ways that spacetime can behave far more weirdly than any science fiction creation; you also drives home just how big our universe really is.

Chris Farnell’s Fermi’s Progress stories do use a faster-than-light spacecraft, but it is one that destroys every planet in its wake.

Chris Farnell

Chris Farnell is a freelance writer and the author of a novel, an anthology, a Doctor Who themed joke book and some supplementary RPG material. He…

Covering the business and politics of space

China’s Chang’e-6 is carrying a surprise rover to the moon

• Click to share on X (Opens in new window)
• Click to share on Facebook (Opens in new window)
• Click to share on LinkedIn (Opens in new window)
• Click to share on Reddit (Opens in new window)
• Click to email a link to a friend (Opens in new window)
• Click to share on Clipboard (Opens in new window)

HELSINKI — China’s Chang’e-6 spacecraft appears to carry a previously undisclosed lunar rover as part of the mission’s far side exploration plans.

Chang’e-6 launched on a Long March 5 rocket from Wenchang early May 3. The mission will attempt to bring back to Earth the first ever samples from the lunar far side. 

China had disclosed objectives, a landing site and science payloads for the mission ahead of launch. However, following launch, the spacecraft’s maker, the China Academy of Space Technology (CAST), revealed an image showing a rover attached to the mission lander. 

Chang’e-6 is a backup to the 2020 Chang’e-5 nearside sample return mission. With that mission successful, Chang’e-6 has been repurposed for a more ambitious lunar far side sampling mission. A similar process saw the backup Chang’e-4 mission land in Von Kármán crater on the lunar far side, following the success of the Chang’e-3 lander and rover mission.

The Chang’e-6 mission includes new, international payloads —from France, Sweden, Italy, and a Pakistani cubesat—and now an additional rover, something not carried by Chang’e-5.

Little is known about the rover, but a mention of a Chang’e-6 rover is made in a post from the Shanghai Institute of Ceramics (SIC) under  the Chinese Academy of Sciences (CAS). It suggests the small vehicle carries an infrared imaging spectrometer.

Yeah, okay. That looks like a previously undisclosed mini rover on the side of the Chang'e-6 lander lol. Via CAST: https://t.co/gS0Jy5L9hw pic.twitter.com/9vvTnribpl — Andrew Jones (@AJ_FI) May 3, 2024

The payload would utilize how different minerals and compounds absorb and emit infrared radiation in characteristic ways to determine the composition of rocks, soil, and regolith on the lunar surface. This could be used for water detection. 

It is not clear how the rover, attached to the side of the lander, will descend to the surface. It could be released, or use a foldout ladder or other mechanism. The rover may communicate with the lander using WiFi. Given the diminutive size of the vehicle and short lifetime of the mission lander, it is likely the rover will have limited operational time and objectives.

Surprise packages  

It is not the first time China has included bonus spacecraft on missions. China’s Tianwen-1 Mars provided a series of punctuated surprises. It first released a disposable spacecraft while on its transfer orbit, taking pictures of the Tianwen-1 orbiter in deep space on its way to Mars.

The Zhurong rover , which landed on the Red Planet as part of the mission, also dropped a camera. This imaged the posing rover and used WiFi to send images to Zhurong.

The Tianwen-1 orbiter then repeated the selfie trick with another detachable camera while in orbit around Mars.

Chang’e-6 mission timeline

Chang’e-6 is likely to reach the moon late Tuesday Eastern (early Wednesday UTC, May 8) and enter lunar orbit. China has yet to publish a clear, official timeline for the mission. It is however expected to last 53 days from launch till landing, according to information published by the Deep Space Exploration Laboratory (DSEL) under the China National Space Administration (CNSA).

Lighting conditions over the target landing area within Apollo crater will likely not be immediately suitable for a landing and surface operations. Sunset over Apollo crater will occur early UTC May 13, according to moon observation software. 

Sunrise will occur May 28, meaning Chang’e-6 will likely attempt to land early June. This means the spacecraft will spend more than three weeks in lunar orbit before attempting landing. Timing of the attempt will be dependent on the spacecraft’s orbit and constraints regarding surface lighting conditions for generating power. 

Sampling operations will, as with Chang’e-5, likely be wrapped up within 48 hours of landing. Samples will be sent into lunar orbit via an ascent vehicle, which will then track the Chang’e-6 orbiter. Based on the earlier mission, the pair will likely rendezvous and dock around two days after launch, with the ascender to be discarded a further couple of days later. 

The orbiter would then prepare to leave lunar orbit at a calculated time. It would then release a reentry capsule just ahead of its return to Earth, around June 25. The orbiter will likely fire its engines to send the spacecraft onto a secondary mission, should it have remaining propellant. The Chang’e-5 orbiter visited Sun-Earth Lagrange point 1 and entered a lunar distant retrograde orbit as part of extended missions.

If successful, samples delivered by the Chang’e-6 mission could change our understanding of the Earth and moon. They could also provide new clues as to the history of the early solar system.

Andrew Jones

Andrew Jones covers China's space industry for SpaceNews. Andrew has previously lived in China and reported from major space conferences there. Based in Helsinki, Finland, he has written for National Geographic, New Scientist, Smithsonian Magazine, Sky... More by Andrew Jones

Sign up for a SpaceNews newsletter

Get top stories, military space news and more delivered to your inbox.

• Cover Letters
• Jobs I've Applied To
• Saved Searches
• Subscriptions

Marine Corps

Coast guard.

• Space Force
• Military Podcasts
• Benefits Home
• Military Pay and Money
• Veteran Health Care
• VA eBenefits
• Veteran Job Search
• Military Skills Translator
• Upload Your Resume
• Veteran Employment Project
• Vet Friendly Employers
• Career Advice
• Military Life Home
• Military Trivia Game
• Veterans Day
• Spouse & Family
• Military History
• Discounts Home
• Featured Discounts
• Veterans Day Restaurant Discounts
• Electronics
• Join the Military Home
• Contact a Recruiter
• Military Fitness
• Boeing Is on the Verge of Launching Astronauts Aboard New Capsule, the Latest Entry to Space Travel

CAPE CANAVERAL, Fla. (AP) — After years of delays and stumbles, Boeing is finally poised to launch astronauts to the International Space Station for NASA.

It’s the first flight of Boeing’s Starliner capsule with a crew on board, a pair of NASA pilots who will check out the spacecraft during the test drive and a weeklong stay at the space station.

NASA turned to U.S. companies for astronaut rides after the space shuttles were retired. Elon Musk's SpaceX has made nine taxi trips for NASA since 2020, while Boeing has managed only a pair of unoccupied test flights.

Boeing program manager Mark Nappi wishes Starliner was further along. “There’s no doubt about that, but we’re here now.”

The company's long-awaited astronaut demo is slated for liftoff Monday night.

Provided this tryout goes well, NASA will alternate between Boeing and SpaceX to get astronauts to and from the space station.

A look at the newest ride and its shakedown cruise:

THE CAPSULE 

White with black and blue trim, Boeing's Starliner capsule is about 10 feet (3 meters) tall and 15 feet (4.5 meters) in diameter. It can fit up to seven people, though NASA crews typically will number four. The company settled on the name Starliner nearly a decade ago, a twist on the name of Boeing’s early Stratoliner and the current Dreamliner.

No one was aboard Boeing’s two previous Starliner test flights. The first, in 2019, was hit with software trouble so severe that its empty capsule couldn’t reach the station until the second try in 2022. Then last summer, weak parachutes and flammable tape cropped up that needed to be fixed or removed.

Veteran NASA astronauts Butch Wilmore and Suni Williams are retired Navy captains who spent months aboard the space station years ago. They joined the test flight after the original crew bowed out as the delays piled up. Wilmore, 61, is a former combat pilot from Mount Juliet, Tennessee, and Williams, 58, is a helicopter pilot from Needham, Massachusetts. The duo have been involved in the capsule’s development and insist Starliner is ready for prime time, otherwise they would not strap in for the launch.

“We’re not putting our heads in the sand,” Williams told The Associated Press. “Sure, Boeing has had its problems. But we are the QA (quality assurance). Our eyes are on the spacecraft.”

THE TEST FLIGHT 

Starliner will blast off on United Launch Alliance’s Atlas V rocket from Cape Canaveral Space Force Station. It will be the first time astronauts ride an Atlas since NASA’s Project Mercury, starting with John Glenn when he became the first American to orbit the Earth in 1962. Sixty-two years later, this will be the 100th launch of the Atlas V, which is used to hoist satellites as well as spacecraft.

“We’re super careful with every mission. We’re super, duper, duper careful" with human missions, said Tory Bruno, CEO of ULA, a joint venture of Boeing and Lockheed Martin.

Starliner should reach the space station in roughly 26 hours. The seven station residents will have their eyes peeled on the approaching capsule. The arrival of a new vehicle is "a really big deal. You leave nothing to chance,” NASA astronaut Michael Barratt told the AP from orbit. Starliner will remain docked for eight days, undergoing checkouts before landing in New Mexico or elsewhere in the American West.

STARLINER VS. DRAGON 

Both companies’ capsules are designed to be autonomous and reusable. This Starliner is the same one that made the first test flight in 2019. Unlike the SpaceX Dragons, Starliner has traditional hand controls and switches alongside touchscreens and, according to the astronauts, is more like NASA’s Orion capsules for moon missions. Wilmore and Williams briefly will take manual control to wring out the systems on their way to the space station.

NASA gave Boeing, a longtime space contractor, more than $4 billion to develop the capsule, while SpaceX got $2.6 billion. SpaceX already was in the station delivery business and merely refashioned its cargo capsule for crew. While SpaceX uses the boss' Teslas to get astronauts to the launch pad, Boeing will use a more traditional “astrovan” equipped with a video screen that Wilmore said will be playing “Top Gun: Maverick.”

One big difference at flight’s end: Starliner lands on the ground with cushioning airbags, while Dragon splashes into the sea.

THE FUTURE 

Boeing is committed to six Starliner trips for NASA after this one, which will take the company to the station’s planned end in 2030. Boeing’s Nappi is reluctant to discuss other potential customers until this inaugural crew flight is over. But the company has said a fifth seat will be available to private clients. SpaceX periodically sells seats to tycoons and even countries eager to get their citizens to the station for a couple weeks.

Coming soon: Sierra Space’s mini shuttle, Dream Chaser, which will deliver cargo to the station later this year or next, before accepting passengers.

You May Also Like

U.S. Marines joined Filipino counterparts on May 5, 2024, for a mock battle at a telling location: a small, remote territory...

Prior to the policy update, which was publicized in a May 1 press release, if an airman began seeking treatment for mental...

Staff Sgt. Gordon Black flew to China and eventually to the city in southeastern Russia to meet with the woman, Aleksandra...

A few hours after Hamas’ announcement, Israel rejected the proposal — which was different from one the two sides had been...

Military News

• Investigations and Features
• Military Opinion

Select Service

• National Guard

Most Popular Military News

A 7th Infantry Division soldier at Joint Base Lewis-McChord in Washington state was accidentally shot April 25 by a 1st...

The Marine Corps needs more counterintelligence and human intelligence specialists, also known as CI/HUMINT, and is offering...

Five sailors were medically evacuated for additional care to a hospital in Georgia, though four of them were released after...

He joined the U.S. Air Force as a teenager and flew more than 300 combat missions during the Vietnam War.

Air National Guard leaders and enlisted Guardsmen on Friday called a legislative proposal to move units focused on space...

Latest Benefits Info

• Burial at Sea: A Time-Honored Tradition
• 4 Tips for Flying Space-A
• The Mental Burden of Using Military Benefits
• Fertility Benefits for Active-Duty Service Members
• Military Child Care Fees

More Military Headlines

Senior Airman Roger Fortson, 23, was assigned to the 4th Special Operations Squadron at Hurlburt Field, which flies AC-130J...

• Gordon and Aleksandra: Videos, Photos Show Relationship Between Detained Soldier and Russian Woman
• Secretive Army Group’s Recruiting Video Is Chock-Full of Hidden Meanings, Viewers Say
• Russia Detains US Soldier over Alleged Criminal Misconduct
• Air Force Pilots Now Can Start Mental Health Treatment and Won't Immediately Be Pulled from Flight Status
• Special Operations Airman Shot and Killed by Florida Police During Disturbance in Apartment Building
• Dick Rutan, Who Set an Aviation Milestone When He Flew Nonstop Around the World, Is Dead at 85
• How Shannon Kent Became a Trailblazer Among US Special Operations Forces
• Navy Hopes to Have Beleaguered USS Boxer Deploy This Summer After Fixes

Military Benefits Updates

• Marines' New Amphibious Combat Vehicle Makes Operational Debut in Annual Philippines Exercise
• US and Philippine Forces Stage Combat Drills near Strategic Channel Off Southern Taiwan
• More than 100 Junior Marine Promotions Delayed Due to Computerized Clerical Error
• Massachusetts Woman Accused of Driving into Fenway Park, Crashing into Coast Guard Base: 'We Are All Going to Be in a Movie'
• Coast Guard Relieves Its Top Reserve Enlisted Leader After Investigation into Misconduct
• What We Know About Various Investigations Stemming from Key Bridge Collapse

Entertainment

• The Best Games to Buy Right Now, No Matter Your Current Pay Level
• Pierce Brosnan Returns to the World of Espionage in 'A Spy's Guide to Survival'
• 9 Games You Can Fit in Your Ruck and Play in the Field

WNBA will add charter flights on full-time basis this season

The WNBA plans to start a full-time charter flights program beginning this season, commissioner Cathy Engelbert announced Tuesday.

“This is a pretty historic moment for the league,” she told the Associated Press Sports Editors in New York. “I think players will be thrilled.”

The new travel program will launch “as soon as we can logistically get planes in places,” Engelbert said. She said funding an entire season of charter travel will cost about $25 million per year for the next two years.

Advertisement

News of a full charter program is momentous for the WNBA, which will begin its 28th season on May 14 as viewership numbers are skyrocketing and a new crop of stars are entering the league. However, Engelbert’s comments also came as a surprise, at least to some around the sport. As of mid-afternoon on Tuesday, multiple general managers, who are not authorized to discuss the matter publicly, told The Athletic they were not made aware of changes to the travel plans prior to Engelbert’s announcement.

“I think everybody’s immediate response is great. What it all looks like, we’re still gathering information. We don’t know,” Aces coach Becky Hammon said. “But I think it’s definitely a good thing for our players in our league. and Everybody’s very happy, they’re not going to have to stand in security lines as much or as long.” Fever coach Christie Sides called the move a “turning point” on social media.

Incredible TURNING POINT in our league! Extremely happy for the players! They deserve this! #GoFever https://t.co/92sgGa0fgr — Christie Sides (@ChristieSides) May 7, 2024

Travel accommodations have long been a source of consternation for players around the league, which primarily uses commercial flights to travel to road games. The CBA requires teams to book economy-plus tickets for players, and players must pay out of pocket for first-class accommodations. The WNBPA has previously maintained that existing travel conditions pose health and safety issues. A full charter program would eliminate the possibility of unwanted interactions, similar to what Phoenix Mercury center Brittney Griner encountered last June, when she was harassed in Dallas Fort Worth Airport while on a road trip by a social media provocateur.

Pickman: Why WNBA charter flights should no longer be considered 'competitive advantages'

Players have also dealt with delays and cancellations through the years, and frequent coach travel isn’t ideal for tall athletes.

Tuesday’s announcement comes in the wake of the league making smaller changes to travel accommodations in recent years. Last season, the WNBA expanded its charter policy and allowed private flights for the entirety of the postseason and select regular-season games, such as back-to-back contests, at a cost of $4 million. Engelbert said that with the league operating on a condensed schedule due to the mid-season Olympic break, there will be 14 back-to-back games this season where charter flights will be utilized.

Prior to April’s WNBA Draft, Engelbert reiterated that the WNBA was not going to “jeopardize the financial viability of this league” to implement a season-long, league-wide charter program. She had stressed the importance of the upcoming media rights negotiations (and in turn an expected significant revenue boost) as a way to achieve this. Its current deal with ESPN runs through 2025.

“Given we have teams moving to bigger arenas, they’re selling out bigger arenas. Given the momentum and business is booming at the team level — also at the league level — could only lead to our corporate partnership sales. We’re seeing a lot of uptick there,” she said in explaining the timing of why the league was planning to put on a full-charter program now. “You need a long-term economic model to fund something as expensive as charter for a whole season, for 12, soon to be 13, 16 teams. You need that long-term revenue model, and we haven’t had it.”

WNBPA executive director Terri Jackson, however, had previously argued that the league did not have to wait for all teams to be able to fly charter for it to go into effect. The New York Liberty had been fined a league-record $500,000 for violating the collective bargaining agreement after their repeated use of charter planes during the second half of the 2021 season. Las Vegas Aces owner Mark Davis has also advocated for teams to have the option to use charter travel.

The upcoming WNBA season appears to be its most anticipated in years. April’s Draft averaged a record 2.446 million viewers, a 307 percent increase in viewership over last year, and was the most-viewed WNBA telecast since 2000. A ratings boost is expected to follow into the regular season, where Indiana Fever guard Caitlin Clark and Chicago Sky forward Angel Reese have further bridged the connection between the college game and professional level. South Carolina’s 87-75 win over Clark and Iowa on April 7 averaged 18.9 million viewers, the most-viewed women’s college basketball game ever and the most-viewed college basketball game (men’s or women’s) on record for an ESPN platform. The 2024 NCAA Women’s Final Four was the most-viewed on record, and the tournament as a whole was up 121 percent from 2023.

WNBPA president Nneka Ogwumike released a statement , saying: “I am thrilled to see a significant change in policy that will permit and provide charter travel across all teams throughout the 2024 season and going forward. On behalf of the players, I express my appreciation and support for a bold move by the Commissioner and team governors that in turn shows that they understand and value the health and safety of the players. It is time to be transformational. It’s time to bet on women!”

— The Athletic ’s Sabreena Merchant contributed to this report.

(Photo of Cathy Engelbert: Sarah Stier / Getty Images)

Get all-access to exclusive stories.

Subscribe to The Athletic for in-depth coverage of your favorite players, teams, leagues and clubs. Try a week on us.

Ben Pickman is a staff writer for The Athletic covering the WNBA and women’s college basketball. Previously, he was a writer at Sports Illustrated where he primarily covered women’s basketball and the NBA. He has also worked at CNN Sports and the Wisconsin Center for Journalism Ethics. Follow Ben on Twitter @ benpickman

Is it passé to say spaceflight is passé? Parallels between 1968 and 2023 unmistakable

Groundbreaking space missions, critics on the ground, breakneck changes in society, history repeats itself.

• David M. Shribman is the former executive editor of the Pittsburgh Post-Gazette.

VERO BEACH, Fla.—I saw it lift into the dusky heavens, reaching upward in a stunning ballet of determination and grace, creeping across the sky in an orange streak, stretching toward earth orbit. And somehow the rise of the SpaceX Falcon-Heavy rocket defied the notion that there is no revelation in repetition.

Americans have been launching rockets from Florida for 73 years; the first one was on July 24, 1950, a date hardly anyone marks or even is aware of. Since Project Apollo, which catapulted men to the moon, ended 48 years ago, and the eclipse of the Space Shuttle, which mounted 135 missions, spaceflight prompted a certain ennui. The days when a black-and-white television atop a tall metal tower was wheeled into classrooms for schoolchildren to witness a Project Mercury launch became a fading memory, like the lyrics of a Shelley Fabares song.

But suddenly it is passé to say that spaceflight is passé.

The past few weeks have proved that. The astronauts who will return to lunar orbit on Artemis II were identified to much fanfare and much public interest. A Jupiter Icy Moons Explore satellite, known as “Juice,” took off from the Guiana Space Center in Kourou, French Guiana, on a mission that will take it through 25 flybys of Jupiter’s Callisto, Europa and Ganymede moons—“one of the most exciting missions we have ever flown in the solar system,” in the characterization of Josef Aschbacher, the head of the European Space Agency, and “by far the most complex.”

And there is more. The Starship rocket lifted off the pad in Southern Texas, cleared the launchpad, and flew for four minutes before collapsing into a spectacular fireball—and yet SpaceX declared the mission a great success. Mission personnel from a private Japanese company may have lost contact with the ispace lunar lander, but the  Hakuto-R Mission 1 vehicle is presumed to have crashed in the Atlas Crater on the near side of the moon—like the Starship, an achievement amid disappointment.

The $97 million SpaceX rocket that slipped the surly bounds of earth recently was carrying satellites designed to improve internet service in the Americas, Europe, the Middle East, and the Asia Pacific region, with another satellite designed to provide high speed internet to remote areas in Alaska. Neither their form nor function was remotely conceivable when the Apollo 8 astronauts circled the moon at Christmastime in 1968, sending unforgettable pictures of their home planet and reading from the Book of Genesis.

That was 55 years ago, and yet the parallels between 1968 and 2023 are unmistakable: Social tensions. Cultural upheaval. Political divisions. A sense of despair. And yet when Bill Anders, Jim Lovell and Frank Borman began reading the verses of the Bible, there was a glimmer of hope on the old planet.

“We could have a moment like that in a year or so from now when the Artemis astronauts return to moon orbit,” said Jennifer Levasseur, curator at the National Air and Space Museum. “There is something about the state of the world today that seems similar to 1968. It makes me think that this is just right time for something like this. We are building to a pretty big moment.”

Jeremy Hansen, the Canadian astronaut who will travel aboard the first manned Artemis mission, believes so. “How do we actually get eight billion people to row in the same direction and work on [our] problems?” he asked when the Artemis astronauts submitted to a Canadian Press interview. “Because these are global problems. We can do great things together. We can do better as a human race. And here’s one small example.”

The editorialists at Canada’s Globe and Mail newspaper picked up the theme. “Ours is a world and a moment that sorely needs a reason to look up in astonished unison,” they wrote. “We don’t get many shared experiences any more. Our histories, our entertainment, our windows on the world – even the facts of our basic reality – are fragmented into choose-your-own-adventure shards.”

Colonel Hansen is the lineal descendant of Marc Garneau, the first Canadian in space, the way the three American Artemis astronauts are the descendants of Alan Shepard, the first American in space. “The Apollo lunar missions drove innovation in ways never imagined, but they brought us more,” Mr. Garneau told me. “They left us proud and even awed by what we accomplished. They gave us confidence. They made us realize we could achieve the extraordinarily difficult. They brought us together and inspired humanity. They moved us forward. We need to build on that.”

Everyone who has been into space feels that way. Jay Apt, who flew on four Space Shuttle missions, one as commander, believes space travel is an antidote to earthbound lassitude and public pessimism.

 “Optimism is essential to provide the energy people need to do almost anything outside of their daily routine, whether it be founding a small business, discovering the secrets of electricity, or having children,” he said. “Exploration in pretty much any era is inherently optimistic and draws the best from optimistic people, which is why I personally get a thrill seeing the images from space telescopes, Earth views from the space station, and can't wait for the photos and videos from the crews that will circle and land on the moon in the decades to come.”

He is not alone. Ms. Levasseur, the museum curator, sees a definite change in the way people mingle amid the space capsules on the display floor. “I see a connection that young people have with space program I haven’t seen before,” she said. “It’s palpable.”  

Americans haven’t always felt that way. Dwight Eisenhower, who was no romantic, was skeptical of mounting a space effort even after the Soviet Union launched Sputnik, the first satellite, in 1957. “I’d like to know what’s on the other side of the moon,” he said, “but I won’t pay to find out this year.” When his successor, John F. Kennedy, launched the American effort to reach the moon, Mr. Eisenhower said, “Anybody who would spend $40 billion in a race to the moon for national prestige is nuts.”

Nuts we were, and nuts we are.

“We choose to go to the Moon in this decade and do the other things, not because they are easy,” Mr. Kennedy said in his challenge to NASA, “but because they are hard." It still is hard, but away we go.

David M. Shribman is the former executive editor of the Pittsburgh Post-Gazette. Email  [email protected] . Twitter:  @ShribmanPG