• The Magazine
  • Stay Curious
  • The Sciences
  • Environment
  • Planet Earth

Will Humans Ever Go Faster Than Light?

Why can't we travel faster than the speed of light find out what complications arise as physicists explore light speed..

Speed of light

Einstein’s special theory of relativity governs our understanding of both the flow of time and the speed at which objects can move. In special relativity, the speed of light is the ultimate speed limit to the universe. Nothing can travel faster than it. Every single moving object in the universe is constrained by that fundamental limit.

Speed of Light and Sound

This isn’t something like the speed of sound . Early scientists wondered if we could ever go faster than that speed, not because of some fundamental rule of the universe, but because we didn’t know if our engineering and materials science capabilities could withstand the extreme turbulence generated by moving at such speeds. But everyday objects already surpass the speed of sound. For example, the crack of a whip is caused by the tip creating a sonic boom as it travels faster than the sound speed.

Read More: Is There a Particle That Can Travel Back in Time?

The problem with trying to surpass the speed of light is that as you go faster, the more kinetic energy you have. But relativity tells us that energy is the same as mass, so the faster you go the more massive you become (and yes, this means that a moving baseball has more mass than one standing still, but that’s a tiny effect).

As you approach the speed of light, your mass balloons up to infinity. The closer you get to the speed of light, the more out of control your mass becomes. With higher masses, you must push yourself harder to accelerate, and you quickly find yourself in a position where it would take an infinite amount of energy to overcome light speed.

Exploring Light Speed

This isn’t just a matter of clever engineering or figuring out some trick – this is built into the fabric of the universe.

That said, there are proposals out there for designing specialized devices that could supposedly overcome this limit without outright breaking relativity. These concepts work because special relativity is a law of local physics: It tells you that you can never measure nearby motion going faster than light speed.

For example, a wormhole could send you to a distant destination faster than you could go traveling normally through space, even though you could travel down the wormhole as slowly as you want. The “ Alcubierre drive ” is essentially a warp drive, deforming spacetime near you so that it can pull you forward as fast as you want to go – even faster than light – without once even firing a rocket.

Read More: Black Holes Are Accelerating The Expansion Of The Universe, Say Cosmologists

Negative Mass and Backward Time Travel

But these fanciful ideas suffer from two drawbacks. For one, to function they each require the use of some exotic form of matter, namely matter that has negative mass . Negative mass is truly weird. If you were to drop a ball of negative mass, it would fly up. If you kicked the ball, it would roll in the opposite direction, and so on. It would completely break everything we know about movement and momentum, and we have absolutely no examples of negative mass existing in our universe. Without negative mass, you can’t build a wormhole or a warp drive.

Second, the ability to go faster than light automatically permits backward time travel. As soon as you concoct methods to cheat the speed of light, you can set up scenarios where signals (or spaceships) can return to their origin point before they departed. This sets up all sorts of messy causality-violating situations and paradoxes, like dropping off a bomb to destroy your spaceship before it’s departed – but unless it departs, the bomb never gets delivered.

Read More: What Is the Grandfather Paradox of Time Travel?

Is Faster Than Light Travel Possible?

Since causality seems kind of important in our universe, with the past staying safely in the past and causes always preceding effects, violating that aspect of reality also seems like a no-go.

The speed of light limit is baked into the most fundamental relationship in the universe: the relationship between space and time as expressed through special relativity. Every single time we test that theory, we are also testing every other aspect of the theory, including its limitations of light speed. And special relativity is perhaps one of the most well-tested theories in all of science. For over a century, it has stood strong.

This isn’t to say that someday in the far future, humanity couldn’t concoct some new theory of physics that completely rewrites our understanding of speed, space, time and causality. Which makes it impossible to outright rule out faster-than-light travel. But for now it seems like we, and everything else in the universe, is permanently stuck in the slow lane.

Read More: Why Can't We Reverse the Arrow of Time?

Article Sources:

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review them for accuracy and trustworthiness. Review the sources used below for this article:

Britannica. Special relativity

Britannica. Speed of light

Britannica. Speed of sound

Quanta Magazine. Physicists Create a Holographic Wormhole Using a Quantum Computer

Phys.org. What is the Alcubierre "warp" drive?

NASA.gov. Negative Mass in Contemporary Physics

  • materials science
  • space exploration
  • subatomic particles
  • transportation
  • black holes

Sign up for our weekly science updates.

Save up to 40% off the cover price when you subscribe to Discover magazine.


Life's Little Mysteries

Can anything travel faster than the speed of light?

Does it matter if it's in a vacuum?

Artist's impression of beams of light

In 1676, by studying the motion of Jupiter's moon Io, Danish astronomer Ole Rømer calculated that light travels at a finite speed. Two years later, building on data gathered by Rømer, Dutch mathematician and scientist Christiaan Huygens became the first person to attempt to determine the actual speed of light, according to the American Museum of Natural History in New York City. Huygens came up with a figure of 131,000 miles per second (211,000 kilometers per second), a number that isn't accurate by today's standards — we now know that the speed of light in the "vacuum" of empty space is about 186,282 miles per second (299,792 km per second) — but his assessment showcased that light travels at an incredible speed.

According to Albert Einstein 's theory of special relativity , light travels so fast that, in a vacuum, nothing in the universe is capable of moving faster. 

"We cannot move through the vacuum of space faster than the speed of light," confirmed Jason Cassibry, an associate professor of aerospace engineering at the Propulsion Research Center, University of Alabama in Huntsville.

Question answered, right? Maybe not. When light is not in a vacuum, does the rule still apply?

Related: How many atoms are in the observable universe?

"Technically, the statement 'nothing can travel faster than the speed of light' isn't quite correct by itself," at least in a non-vacuum setting, Claudia de Rham, a theoretical physicist at Imperial College London, told Live Science in an email. But there are certain caveats to consider, she said. Light exhibits both particle-like and wave-like characteristics, and can therefore be regarded as both a particle (a photon ) and a wave. This is known as wave-particle duality.

If we look at light as a wave, then there are "multiple reasons" why certain waves can travel faster than white (or colorless) light in a medium, de Rham said. One such reason, she said, is that "as light travels through a medium — for instance, glass or water droplets — the different frequencies or colors of light travel at different speeds." The most obvious visual example of this occurs in rainbows, which typically have the long, faster red wavelengths at the top and the short, slower violet wavelengths at the bottom, according to a post by the University of Wisconsin-Madison . 

Sign up for the Live Science daily newsletter now

Get the world’s most fascinating discoveries delivered straight to your inbox.

When light travels through a vacuum, however, the same is not true. "All light is a type of electromagnetic wave, and they all have the same speed in a vacuum (3 x 10^8 meters per second). This means both radio waves and gamma rays have the same speed," Rhett Allain, a physics professor at Southeastern Louisiana University, told Live Science in an email.

So, according to de Rham, the only thing capable of traveling faster than the speed of light is, somewhat paradoxically, light itself, though only when not in the vacuum of space. Of note, regardless of the medium, light will never exceed its maximum speed of 186,282 miles per second.

Universal look

According to Cassibry, however, there is something else to consider when discussing things moving faster than the speed of light.

"There are parts of the universe that are expanding away from us faster than the speed of light, because space-time is expanding," he said. For example, the Hubble Space Telescope recently spotted 12.9 billion year-old light from a distant star known as Earendel. But, because the universe is expanding at every point, Earendel is moving away from Earth and has been since its formation, so the galaxy is now 28 billion light years away from Earth.

In this case, space-time is expanding, but the material in space-time is still traveling within the bounds of light speed.

Related: Why is space a vacuum?

Diagram of the visible color spectrum

So, it's clear that nothing travels faster than light that we know of, but is there any situation where it might be possible? Einstein's theory of special relativity, and his subsequent theory of general relativity, is "built under the principle that the notions of space and time are relative," de Rham said. But what does this mean? "If someone [were] able to travel faster than light and carry information with them, their notion of time would be twisted as compared to ours," de Rham said. "There could be situations where the future could affect our past, and then the whole structure of reality would stop making sense."

This would indicate that it would probably not be desirable to make a human travel faster than the speed of light. But could it ever be possible? Will there ever be a time when we are capable of creating craft that could propel materials — and ultimately humans — through space at a pace that outstrips light speed? "Theorists have proposed various types of warp bubbles that could enable faster-than-light travel," Cassibry said.

But is de Rham convinced?

"We can imagine being able to communicate at the speed of light with systems outside our solar system ," de Rham said. "But sending actual physical humans at the speed of light is simply impossible, because we cannot accelerate ourselves to such speed.

"Even in a very idealistic situation where we imagine we could keep accelerating ourselves at a constant rate — ignoring how we could even reach a technology that could keep accelerating us continuously — we would never actually reach the speed of light," she added. "We could get close, but never quite reach it."

Related: How long is a galactic year?

This is a point confirmed by Cassibry. "Neglecting relativity, if you were to accelerate with a rate of 1G [Earth gravity], it would take you a year to reach the speed of light. However, you would never really reach that velocity because as you start to approach lightspeed, your mass energy increases, approaching infinite. "One of the few known possible 'cheat codes' for this limitation is to expand and contract spacetime, thereby pulling your destination closer to you. There seems to be no fundamental limit on the rate at which spacetime can expand or contract, meaning we might be able to get around this velocity limit someday."

— What would happen if the speed of light were much lower?

— What if the speed of sound were as fast as the speed of light?

— How does the rubber pencil illusion work?

Allain is similarly confident that going faster than light is far from likely, but, like Cassibry, noted that if humans want to explore distant planets, it may not actually be necessary to reach such speeds. "The only way we could understand going faster than light would be to use some type of wormhole in space," Allain said. "This wouldn't actually make us go faster than light, but instead give us a shortcut to some other location in space."

Cassibry, however, is unsure if wormholes will ever be a realistic option.

"Wormholes are theorized to be possible based on a special solution to Einstein's field equations," he said. "Basically, wormholes, if possible, would give you a shortcut from one destination to another. I have no idea if it's possible to construct one, or how we would even go about doing it." Originally published on Live Science.

Joe Phelan

Joe Phelan is a journalist based in London. His work has appeared in VICE, National Geographic, World Soccer and The Blizzard, and has been a guest on Times Radio. He is drawn to the weird, wonderful and under examined, as well as anything related to life in the Arctic Circle. He holds a bachelor's degree in journalism from the University of Chester. 

Space photo of the week: 'God's Hand' leaves astronomers scratching their heads

Why can't we see the far side of the moon?

James Webb telescope detects 1-of-a-kind atmosphere around 'Hell Planet' in distant star system

Most Popular

  • 2 Cave of Crystals: The deadly cavern in Mexico dubbed 'the Sistine Chapel of crystals'
  • 3 'The most critically harmful fungi to humans': How the rise of C. auris was inevitable
  • 4 2,500-year-old Illyrian helmet found in burial mound likely caused 'awe in the enemy'
  • 5 32 of the most colorful birds on Earth
  • 2 Roman-era skeletons buried in embrace, on top of a horse, weren't lovers, DNA analysis shows
  • 3 Papua New Guineans, genetically isolated for 50,000 years, carry Denisovan genes that help their immune system, study suggests
  • 4 'The most critically harmful fungi to humans': How the rise of C. auris was inevitable

mind can travel faster than light

Lisa Broderick

Time Slips, the Multiverse, and You

Some believe that time travel is possible. but is it and if so, how.

Posted January 9, 2022 | Reviewed by Jessica Schrader

  • The nature of time is one of the biggest mysteries in science. Scientists simply do not understand what time is.
  • The universe has a "speed limit" called the speed of light, faster than which nothing in our universe can travel.
  • The multiverse theory explains how it could be possible for people to have traveled faster than light speed during "time slips."

Source: Angel Glen/Pixabay

The nature of time is one of the biggest mysteries in science. Scientists simply do not understand what time is, at least partially, because it does not behave the same way in all circumstances. For example, did you know that clocks installed on airplanes—or even further away, on satellites—record time at different rates than here on Earth?

We all know that time has a physical component that is measured by clocks. This physical component of time exists because things and people move around in space: the motion of the Earth propels time forward in 24-hour days and 365-day years. We physically experience time because we experience ourselves and things moving around. This is obviously true when you think about different time zones. It isn’t the same time in New York as it is in Sydney because the Earth is moving. In fact, we are all traveling in time at about one second per second. This physical component of time was explained by Einstein who, more than 100 years ago, revolutionized the idea of how time works. He theorized that time and space are inextricably linked together. He also found that the universe has a speed limit of sorts: the speed of light. So while time and space are linked, nothing can travel faster than the speed of light (186,000 miles per second).

But what about otherwise credible reports made by those who claim to have traveled faster than the speed of light? What about reports of actual time travel? The internet is filled with stories about people insisting they experienced jumps in time which are not merely one second per second, but decades or even hundreds of years. These time anomalies, or “time slips,” are paranormal episodes during which someone—or a group of people—somehow experience traveling through time without knowing how or why it occurred.

In one account in Oklahoma in the 1970s, three workers were picking up cattle feeder equipment from a farm and noticed a white house on the property.[1] When they came back the next day, however, the house was not only not there and there was no sign of it ever having been there—yet all three workers saw the same thing the prior day. One possible explanation: the house had existed in a different moment in time, which they collectively experienced as reality.

Whether or not stories like these are to be believed by others, the people who recount them certainly believe them. Given what we know and what we don’t know about how time works, how might these happen?

One explanation is a credible but controversial scientific theory called the multiverse theory. The multiverse theory supposes that an infinite number of worlds exist along different paths in time which arise out of each passing moment, suggesting that different things happen in each universe.[2]

It sounds not only preposterous but also like a lot of work for the universe. Imagine: a new universe traveling along its own, unique timeline created out of every moment of time. This theory suggests there may be an infinite number of universes. It also explains how “time slips” might be real.

Support for the multiverse theory comes from an arcane but scientifically valid Big Bang theory called cosmic inflation.[3] Cosmic inflation refers to a faster-than-light expansion of the universe that may be responsible for spawning an unlimited number of disconnected universes that eternally issue from one another. Cosmic inflation may have happened because, during its earliest instants of formation, the universe was expanding outward from a single point into nothingness. Said another way, the universe’s faster-than-light expansion could be due to the fact that it was expanding into something that was not itself, where the speed of light wouldn’t apply. This may explain just how the universe became so far-flung out of its early chaotic origins.[4]

Whether or not the multiverse, cosmic inflation, and an infinite number of disconnected universes eternally branching off from one another is the way time works remains to be proven by scientists. But the theories are intriguing, and they solve at least one famous problem scientists have with time travel: the grandfather paradox. The grandfather paradox states that if you were to go back in time and kill your grandfather before your father was born, then you wouldn’t exist in the first place to kill him. The multiverse theory solves that paradox in that you could kill a copy of your grandfather in an alternate universe and therefore still have been born in your universe. Of course, it leaves open the question of how you traveled between universes in the first place. Maybe someone experiencing a time slip will one day come back and explain how that works. Maybe you.

Grace Walsh, “Are time slips real? These people certainly think time travel can happen,” Good to Know, January 20, 2020, https://www.goodto.com/family/are-time-slips-real-526367 .

Paul Sutter, “What is multiverse theory?” Live Science, August 23, 2021, https://www.livescience.com/multiverse .

“This is why physicists suspect the Multiverse very likely exists,” Big Think, December 30, 2021, https://bigthink.com/starts-with-a-bang/physicists-multiverse-exists/ .

“Cosmic Inflation,” New Scientist, https://www.newscientist.com/definition/cosmic-inflation/ .

Lisa Broderick

Lisa Broderick holds a B.A. from Stanford and an MBA from Duke. She is a TM Siddha and studied at the Monroe Institute and at the American Institute for Mental Imagery.

  • Find a Therapist
  • Find a Treatment Center
  • Find a Psychiatrist
  • Find a Support Group
  • Find Online Therapy
  • International
  • New Zealand
  • South Africa
  • Switzerland
  • Asperger's
  • Bipolar Disorder
  • Chronic Pain
  • Eating Disorders
  • Passive Aggression
  • Personality
  • Goal Setting
  • Positive Psychology
  • Stopping Smoking
  • Low Sexual Desire
  • Relationships
  • Child Development
  • Therapy Center NEW
  • Diagnosis Dictionary
  • Types of Therapy

March 2024 magazine cover

Understanding what emotional intelligence looks like and the steps needed to improve it could light a path to a more emotionally adept world.

  • Emotional Intelligence
  • Gaslighting
  • Affective Forecasting
  • Neuroscience

This Trick Flips Space and Time

Image no longer available

By Meddling With Spacetime Dimensions, We Could Finally Reach Warp Speed

New research shows that the “superluminal observer” needs three separate time dimensions for a warp-speed math trick that would please even Galileo.

✅ Quick Facts:

  • In new research, the lead scientist explains why just one space and one time aren’t enough for this scenario.
  • Symmetry is a physics concept that goes all the way back to Galileo’s time.

The secret to faster-than-light physics could be to double down on the number of dimensions. Specifically, the solution may lie in three dimensions of time , with just one representing space. The math is deep and complicated, but the ideas may be within our grasp after all. And there’s one math trick at superspeeds that may just “flip” your lid.

The key idea at play is that of a “superluminal observer,” according to research published in December 2022 in the journal Classical and Quantum Gravity. “Superluminal” means faster than light, from super - meaning “more” or “most,” and - luminal like, well, Lumière from Beauty and the Beast, and the lumens that power your home movie projector. The superluminal observer is a hypothetical thing that is looking at the universe while traveling faster than light. It’s you in your Star Trek warp-speed shuttle.

star trek

Superluminal observers are cool because, in a way, they marry together two very different sides of physics: general relativity and quantum mechanics . General relativity is the work embodied by Albert Einstein, which governs how spacetime functions as bodies move around the universe at subluminal, or slower than light, speeds. Quantum mechanics explains how subatomic particles behave, or don’t behave, in very strange ways on the smallest of scales.

The research team—led by theoretical physicist Andrzej Dragan of the University of Warsaw and the National University of Singapore—has theorized that many parts of quantum physics, like indeterminism and superposition , can be explained if you take general relativity and apply its principles to the superluminal observer. In other words, how messy does spacetime get if we take our shuttle up to warp speed? Is everything suddenly in multiple places at once?

Dragan’s new work indicates that it’s at least a possibility. Perhaps more interestingly, the way general relativity becomes quantum phenomena at speeds greater than light doesn’t seem to introduce any causal paradoxes. In earlier work , published in the New Journal of Physics in March 2020, Dragan and his coauthor studied “just” one space dimension and one time dimension, known as 1+1. In the new paper, the researchers upped the ante to include one space dimension and three time dimensions, or 1+3.

When Time and Space Flip Math

Why do we need three time dimensions? To understand, we have to talk about some math. “[D]espite our common perception, time and space are strikingly similar according to relativity, and mathematically the only difference between them is the minus sign somewhere in the equations,” Dragan explains to Popular Mechanics in an email. That’s a small difference in complicated math, but think of the algebra example of the difference of two squares: x² - 16, for example, is the result of (x - 4)(x + 4). With one flipped sign, the middle term in the polynomial falls away.

But when the observer is going faster than the speed of light, the difference in signs also changes. That’s because time and space must flip in the math. “The time of the superluminal observer becomes space of the subluminal one, and their space becomes time,” Dragan says. In other words, the regular, non-light-speed observer’s space and time turn into the time and space, relatively, of the faster-than-light observer. “So their corresponding signs have to interchange.”

In a 1+1 scenario, that means the two dimensions are the same, making it redundant. If 50 = 50, does it matter which 50 is which? (In logic, we call this a tautology.) That means that if we want to truly study space and time as different things, we have to add a second “set” of two dimensions: space and time 1, together, represent space; while time 2 and time 3, together, represent time . It’s not quite the difference of two squares, but we have two balanced sets of dimensions.

The Symmetry in Physics

balls balancing on scale

There’s another interesting aspect to this research, because Dragan’s team wants to show that even at superluminal speeds, physics shows symmetry.

“The idea of symmetry in physics can be traced back to Galileo,” Dragan says. “He noticed that no matter what velocity we move at, as long as that velocity is constant, our physics remains the same. A parrot flying in a moving ship experiences the same dynamical laws as at ‘rest’ on Earth.”

✅ Galileo Galilei was an influential Italian scientist who lived during the 16th and 17th centuries. As an elderly man, he received a life sentence for going public with his belief that Earth orbited the sun!

But our conceptions of physics are limited by the long-running (and reasonable!) belief that nothing can travel faster than light, Dragan explains. That means the superluminal observer, by definition, exists as a kind of exception into which we must work to extend the idea of symmetry. Does it make sense that a superluminal observer would still be subject to symmetry? Is the parrot traveling faster than light still the same as the parrot in the ship or on Earth?

“We argued that this additional limiting assumption isn’t necessary,” Dragan says. He believes symmetry may extend into faster-than-light speeds, and our parrot friend would be just as affected by the same laws of physics while traveling in the warp-speed shuttle.

Toward a Grand Unified Theory

So, this paper isn’t about traveling at warp speed, but instead an analysis of physics to show how we can bring two very different physics branches together. Why is that, itself, so important?

“The idea of more than one time dimension has been considered by others over the years, so that particular premise is not novel,” Harold “Sonny” White, a onetime NASA physicist and the founder of the Limitless Space Institute (LSI), a group that funds and promotes far-out space travel and physics research, tells Popular Mechanics . “But the mathematical framework developed by the authors in this published paper is unique. It would seem the authors’ perceived benefit from the effort is that it establishes a mathematical basis for why we need a field theoretical framework.”

einstein writing equation on blackboard

What is a field theoretical framework? It’s the big picture of physics that can bring everything together. “[I]f we envision the standard models of physics as a Venn diagram, there would be two circles side-by-side that touch at a single tangent point,” White explains. “The idea of a grand unified field theory might be envisioned as a larger circle that encircles both the smaller circles.”

By showing their work, these researchers have pointed out a really specific way in which one big basket of physics—rather than two baskets that we aren’t sure how to carry at the same time—would make more sense in practical and mathematical terms.

Okay, sure, you may be thinking: all this superluminal jabberwocky is interesting. But warp speed itself is science fiction, right? (At least for now: White’s LSI funds education that may eventually lead us elsewhere.) The superluminal observer is just a thought exercise ... right?

Dragan isn’t so sure. “The last remaining question is whether superluminal objects are only a mathematical possibility, or they actually exist in reality,” he concludes. “We believe the latter to be that case, and that is the purpose of our further research.”

That means our warp-speed shuttle, once the most far-out thing science fiction writers could even imagine, could embody an elegant theory that brings together two very different kinds of physics. Indeed, objects in the superluminal mirror may be closer than they appear.

Headshot of Caroline Delbert

Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about everything. Her favorite topics include nuclear energy, cosmology, math of everyday things, and the philosophy of it all. 

preview for Popular Mechanics All Sections

.css-cuqpxl:before{padding-right:0.3125rem;content:'//';display:inline;} Pop Mech Pro: Space .css-xtujxj:before{padding-left:0.3125rem;content:'//';display:inline;}

multicolored painted nebula

How a Lunar Supercollider Could Upend Physics

the greek letter pi, the ratio of the circumference of a circle to its diameter, is drawn in chalk on a black chalkboard with a compass in honor

The History of Pi

close up image of full moon as seen in the northern hemisphere

The Strange Origin of the Hollow Moon Conspiracy

unidentified flying objects, illustration

What Do Alien Space Probes Look Like?

alien exo planet elements of this image furnished by nasa

How NASA’s Next Super Telescope Could Find Aliens

astronaut floating in atmosphere

Will Mars Astronauts Need Sunscreen?

nuclear fusion power generator concept image, 3d rendering

Sunquakes May Be the Key to Nuclear Fusion

ufo flying over new mexico in black and white image

7 Solid Reasons to Actually Believe in Aliens

large asteroid hitting earth

The 7 Greatest Cosmic Threats to Life on Earth

man gazing at sky

Your Guide to Every Stargazing Event in 2024

hubble telescope boomerang nebula

This Is the Coldest Place in the Universe

  • International edition
  • Australia edition
  • Europe edition

Einstein's theory of special relativity

Why you can't travel at the speed of light

A lbert Einstein is famous for many things, not least his theories of relativity. The first, the special theory of relativity, was the one that began the physicist's reputation for tearing apart the classical worldview that had come before. Special relativity, a way of relating the motion of objects in the universe, led scientists to re-evaluate their assumptions about things as fundamental as time and space. And it led to important revelations about the relationship between energy and matter.

Special relativity was published by Einstein in 1905, in a paper titled "On the Electrodynamics of Moving Bodies". He came to it after picking on a conflict he noticed between the equations for electricity and magnetism, which the physicist James Clerk Maxwell had recently developed, and Isaac Newton's more established laws of motion.

Light, according to Maxwell, was a vibration in the electromagnetic field and it travelled at a constant speed in a vacuum. More than 100 years earlier, Newton had set down his laws of motion and, together with ideas from Galileo Galilei, these showed how the speed of an object would differ depend on who was measuring it and how they were moving relative to the object. A ball you are holding will seem still to you, even when you're in a moving car. But that ball will seem to be moving to anyone standing on the pavement.

But there was a problem in applying Newton's laws of motion to light. In Maxwell's equations, the speed of electromagnetic waves is a constant defined by the properties of the material through which the waves move. There is nothing in there that allows the speed of these waves to be different for different people depending on how they were moving relative to each other. Which is bizarre, if you think about it.

Imagine someone sitting in a stationary train, throwing a ball from where he's sitting to the opposite wall, a few metres further down the train from him. You, standing on the station platform, measure the speed of the ball at the same value as the person on the train.

Now the train starts to move (in the direction of the ball), and you again measure the speed of the ball. You would rightly calculate it as higher – the initial speed (ie, when the train was at rest) plus the forward speed of the train. On the train, meanwhile, the game-player will notice nothing different. Your two values for the speed of the ball will be different; both correct for your frames of reference.

Replace the ball with light and this calculation goes awry. If the person on the train were shining a light at the opposite wall and measured the speed of the particles of light (photons), you and the passenger would both find that the photons had the same speed at all times. In all cases, the speed of the photons would stay at just under 300,000 kilometres per second, as Maxwell's equations say they should.

Einstein took this idea – the invariance of the speed of light – as one of his two postulates for the special theory of relativity. The other postulate was that the laws of physics are the same wherever you are, whether on an plane or standing on a country road. But to keep the speed of light constant at all times and for all observers, in special relativity, space and time become stretchy and variable. Time is not absolute, for example. A moving clock ticks more slowly than a stationary one. Travel at the speed of light and, theoretically, the clock would stop altogether.

How much the time dilates can be calculated by the two equations above. On the right, Δt is the time interval between two events as measured by the person they affect. (In our example above, this would be the person in the train.) On the left, Δt' is the time interval between the same two events but measured by an outside observer in a separate frame of reference (the person on the platform). These two times are related by the Lorentz factor (γ), which in this example is a term that takes into account the velocity (v) of the train relative to the station platform, which is "at rest". In this expression, c is a constant equal to the speed of light in a vacuum.

The length of moving objects also shrink in the direction in which they move. Get to the speed of light (not really possible, but imagine if you could for a moment) and the object's length would shrink to zero.

The contracted length of a moving object relative to a stationary one can be calculated by dividing the proper length by the Lorentz factor – if it were possible for an object to reach the speed of light its length would shrink to zero.

It is important to note that if you were the person moving faster and faster, you would not notice anything: time would tick normally for you and you would not be squashed in length. But anyone watching you from the celestial station platform would be able to measure the differences, as calculated from the Lorentz factor. However, for everyday objects and everyday speeds, the Lorentz factor will be close to 1 – it is only at speeds close to that of light that the relativistic effects need serious attention.

Another feature that emerges from special relativity is that, as something speeds up, its mass increases compared with its mass at rest, with the mass of the moving object determined by multiplying its rest mass by the Lorentz factor. This increase in relativistic mass makes every extra unit of energy you put into speeding up the object less effective at making it actually move faster.

As the speed of the object increases and starts to reach appreciable fractions of the speed of light (c), the portion of energy going into making the object more massive gets bigger and bigger.

This explains why nothing can travel faster than light – at or near light speed, any extra energy you put into an object does not make it move faster but just increases its mass. Mass and energy are the same thing – this is a profoundly important result. But that is another story.

  • Albert Einstein
  • A short history of equations
  • Isaac Newton

Comments (…)

Most viewed.

mind can travel faster than light


What If You Traveled Faster Than the Speed of Light?

  • Share Content on Facebook
  • Share Content on LinkedIn
  • Share Content on Flipboard
  • Share Content on Reddit
  • Share Content via Email

speed of light

When we were kids, we were amazed that Superman could travel "faster than a speeding bullet." We could even picture him, chasing down a projectile fired from a weapon, his right arm outstretched, his cape rippling behind him. If he traveled at half the bullet 's speed, the rate at which the bullet moved away from him would halve. If he did indeed travel faster than the bullet, he would overtake it and lead the way. Go, Superman!

In other words, Superman's aerial antics obeyed Newton's views of space and time : that the positions and motions of objects in space should all be measurable relative to an absolute, nonmoving frame of reference [source: Rynasiewicz ].

In the early 1900s, scientists held firm to the Newtonian view of the world. Then a German-born mathematician and physicist by the name of Albert Einstein came along and changed everything. In 1905, Einstein published his theory of special relativity , which put forth a startling idea: There is no preferred frame of reference. Everything, even time, is relative.

Two important principles underpinned his theory. The first stated that the same laws of physics apply equally in all constantly moving frames of reference. The second said that the speed of light — about 186,000 miles per second (300,000 kilometers per second) — is constant and independent of the observer's motion or the source of light. According to Einstein, if Superman were to chase a light beam at half the speed of light, the beam would continue to move away from him at exactly the same speed [source: Stein , AMNH.org ].

These concepts seem deceptively simple, but they have some mind-bending implications. One of the biggest is represented by Einstein's famous equation, E = mc², where E is energy, m is mass and c is the speed of light.

According to this equation, mass and energy are the same physical entity and can be changed into each other. Because of this equivalence, the energy an object has due to its motion will increase its mass. In other words, the faster an object moves, the greater its mass. This only becomes noticeable when an object moves really quickly. If it moves at 10 percent the speed of light, for example, its mass will only be 0.5 percent more than normal. But if it moves at 90 percent the speed of light, its mass will double [source: LBL.gov ].

As an object approaches the speed of light, its mass rises precipitously. If an object tries to travel 186,000 miles per second, its mass becomes infinite, and so does the energy required to move it. For this reason, no normal object can travel as fast or faster than the speed of light.

That answers our question, but let's have a little fun and modify the question slightly.

Almost As Fast As the Speed of Light?

We covered the original question, but what if we tweaked it to say, "What if you traveled almost as fast as the speed of light?" In that case, you would experience some interesting effects. One famous result is something physicists call time dilation , which describes how time runs more slowly for objects moving very rapidly. If you flew on a rocket traveling 90 percent of light-speed, the passage of time for you would be halved. Your watch would advance only 10 minutes, while more than 20 minutes would pass for an Earthbound observer [source: May ]

You would also experience some strange visual consequences. One such consequence is called aberration , and it refers to how your entire field of view would shrink down to a tiny, tunnel-shaped "window" out in front of your spacecraft. This happens because photons (those exceedingly tiny packets of light) — even photons behind you — appear to come in from the forward direction.

In addition, you would notice an extreme Doppler effect , which would cause light waves from stars in front of you to crowd together, making the objects appear blue. Light waves from stars behind you would spread apart and appear red. The faster you go, the more extreme this phenomenon becomes until all visible light from stars in front of the spacecraft and stars to the rear become completely shifted out of the known visible spectrum (the colors humans can see). When these stars move out of your perceptible wavelength, they simply appear to fade to black or vanish against the background.

Of course, if you want to travel faster than a speeding photon, you'll need more than the same rocket technology we've been using for decades.

In a March 2021 paper published in the journal Classical and Quantum Gravity , astrophysicist Erik Lentz of the University of Göttingen in Germany proposed the idea of rearranging space-time to create a warp bubble, inside which a spacecraft might be able to travel at faster-than-light speeds.

Speed of Light FAQ

Is there anything faster than the speed of light, how fast is the speed of light in miles, why is "c" the speed of light, what is the speed of light on earth, lots more information, related articles.

  • Data Sent via Infrared Light Could Make WiFi Hundreds of Times Faster
  • How Light Propulsion Will Work
  • How Light Works
  • American Museum of Natural History. "A Matter of Time. " Amnh.org. (Feb. 16, 2022) https://www.amnh.org/exhibitions/einstein/time/a-matter-of-time
  • Brandeker, Alexis. "What would a relativistic interstellar traveler see?" Usenet Physics FAQ. May 2002. (Feb. 16, 2022J) http://www.desy.de/user/projects/Physics/Relativity/SR/Spaceship/spaceship.html
  • Carl Sagan's Cosmos. "Travels in Space and Time." YouTube. Video uploaded Nov. 27, 2006 (Feb. 16, 2022 ) https://www.youtube.com/watch?v=2t8hUaaZVJg
  • Hawking, Stephen. "The Illustrated Brief History of Time. " Bantam. 1996. (Feb. 16. 2022) https://bit.ly/367UGpZ
  • EurekAlert! "Breaking the warp barrier for faster-than-light travel. " Eurekalert.org. March 9, 2021. (Feb. 16, 2022) https://www.eurekalert.org/news-releases/642756
  • Lawrence Berkeley National Laboratory. "Mass, Energy, the Speed of Light – It's Not Intuitive! " Lbl.gov. 1996. (Feb. 16, 2022) https://www2.lbl.gov/MicroWorlds/teachers/massenergy.pdf
  • Lemonick, Michael D. "Will We Ever Travel at the Speed of Light?" Time. Apr. 10, 2000. (Feb. 16, 2022), 2011) http://content.time.com/time/subscriber/article/0,33009,996616,00.html
  • May, Andrew. "What is time dilation? " LiveScience. Nov. 17, 2021. (Feb. 16, 2022) https://www.livescience.com/what-is-time-dilation
  • NOVA Physics + Math. "Carl Sagan Ponders Time Travel." NOVA. Oct. 12, 1999. (Feb. 16, 2022) http://www.pbs.org/wgbh/nova/physics/Sagan-Time-Travel.html
  • Ptak, Andy. "The Speed of Light in a Rocket." NASA's Imagine the Universe: Ask An Astrophysicist. Jan. 2, 1997. (Feb. 16, 2022) http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970102c.html
  • Rynasiewicz, Robert, "Newton's Views on Space, Time, and Motion."Stanford Encyclopedia of Philosophy. Summer 2014. (Feb. 16, 2022) https://plato.stanford.edu/cgi-bin/encyclopedia/archinfo.cgi?entry=newton-stm
  • Stein, Vicky. "Einstein's Theory of Special Relativity. " Space.com. Sept. 20, 2021. (Feb. 16, 2022) https://www.space.com/36273-theory-special-relativity.html
  • Van Zyl, Miezam (project editor)."Universe: The Definitive Visual Guide." Dorling Kindersley Limited. 2020. (Feb. 16, 2022) https://bit.ly/33q5Mpm.

Please copy/paste the following text to properly cite this HowStuffWorks.com article:

U.S. physicist Albert Einstein delivers a lecture at the offices of the Mt. Wilson Observatory, California.

mind can travel faster than light

Why We Can’t Travel Faster than the Speed of Light: Exploring the Laws of Physics

Traveling faster than the speed of light has fascinated scientists and science fiction enthusiasts for decades. However, despite the many technological advancements and our understanding of the universe, it remains an impossible feat. The laws of physics , specifically the theory of relativity, dictate that nothing can travel faster than the speed of light.

The theory of relativity, developed by Albert Einstein in the early 20th century, is a cornerstone of modern physics. It has been tested and confirmed countless times through experiments and observations. One of its fundamental principles is that the speed of light is an unbreakable barrier. As an object approaches the speed of light , its mass increases, making it harder and harder to accelerate. At the speed of light, an object’s mass would become infinite, requiring infinite energy to continue accelerating.

While it may be disappointing to think that we will never be able to travel faster than the speed of light, the theory of relativity has opened up many other possibilities for space exploration and scientific discovery. It has allowed us to understand the nature of time and space in a previously impossible way and has led to countless breakthroughs in our understanding of the universe.

The Physics of Light Speed

A spaceship hurtles towards a bright, glowing barrier, its engines straining against the impossible speed limit of light

Relativity and the Cosmic Speed Limit

According to Einstein’s theory of relativity, the speed of light is the ultimate speed limit in the universe. This means that nothing can travel faster than the speed of light. The theory of relativity has been tested and verified countless times, and experiments have confirmed its predictions.

One of the key concepts of relativity is that space and time are not separate entities but are instead intertwined in a four-dimensional fabric called spacetime. This means that the faster an object moves through space, the slower it moves through time. As an object approaches the speed of light, time slows down to the point where it appears to stop altogether. This phenomenon is known as time dilation.

Energy Requirements for Near-Light Speed

As an object approaches the speed of light, its mass increases exponentially. This means that as an object gets closer and closer to the speed of light, it requires an exponentially increasing amount of energy to continue accelerating. At the speed of light, an object would have infinite mass and require infinite energy to continue accelerating.

This energy requirement is one of the main reasons why we can’t travel faster than the speed of light. Even if we could somehow overcome the other physical limitations, such as time dilation and the effects of relativity, we would still need an infinite amount of energy to reach the speed of light.

In conclusion, the physics of light speed is a fascinating and complex topic that has puzzled scientists for generations. While we may never be able to travel faster than the speed of light, our understanding of the universe continues to expand as we explore the limits of what is possible.

Technological Limitations

A spaceship approaching a bright barrier, unable to break through

Current Propulsion Systems

The current propulsion systems used in spacecraft, such as chemical rockets and ion thrusters, are not capable of achieving speeds close to the speed of light. Chemical rockets rely on burning fuel to create thrust, which is limited by how much fuel can be carried. On the other hand, Ion thrusters use electric fields to accelerate ions. Still, they also have limitations in terms of the amount of power that can be generated and the efficiency of the acceleration process.

Material Constraints

Another limitation to achieving speeds close to the speed of light is the materials used in spacecraft construction. As an object approaches the speed of light, its mass increases, requiring more energy to accelerate it. This means that the spacecraft must be constructed with materials that can withstand high speeds and energy requirements without breaking down or melting. Currently, no materials are strong enough to withstand the extreme conditions that would be encountered at such high speeds.

In conclusion, the current technological limitations of propulsion systems and materials make it impossible to travel at or faster than the speed of light. While theoretical concepts such as wormholes and warp drive could potentially allow for faster-than-light travel, they are purely hypothetical and have not yet been proven feasible with our current understanding of physics.

Theoretical Possibilities and Challenges

A spaceship hurtles towards a distant star, its engines blazing as it attempts to break the barrier of light speed. The star's light stretches out behind it, illustrating the theoretical challenges of faster-than-light travel

Warp Drives and Alcubierre Theory

One of the most popular theoretical possibilities for faster-than-light travel is a warp drive. This idea is based on the Alcubierre theory, which suggests that space-time could be warped to allow a spacecraft to travel faster than the speed of light.

The warp drive concept is based on creating a space-time bubble around a spacecraft and contracting the space in front of it while expanding the space behind it. This would allow the spacecraft to ride on a wave of space-time, effectively bypassing the speed of light limit.

However, the concept of a warp drive is associated with several challenges. One of the biggest challenges is the amount of energy required to create the space-time bubble. The energy required is estimated to be equivalent to the mass of Jupiter, making it currently impossible to achieve.

Quantum Entanglement and Information Transfer

Another theoretical possibility for faster-than-light travel is based on the concept of quantum entanglement. This is a phenomenon where two particles become entangled and share a quantum state, meaning that the state of one particle is dependent on the state of the other particle, regardless of the distance between them.

The idea is that by entangling particles on Earth and a spacecraft, information could be transferred instantly, effectively allowing for communication and travel faster than the speed of light.

However, there are several challenges associated with this concept as well. One of the main challenges is the fragility of quantum entanglement, which can be disrupted by environmental factors such as temperature and electromagnetic radiation. Additionally, the information transferred through quantum entanglement is limited to the speed of light, meaning that it cannot be used for faster-than-light travel.

Overall, while these theoretical possibilities offer exciting prospects for faster-than-light travel, they are still in the realm of science fiction. The challenges associated with these concepts are significant and will require significant advancements in technology and understanding of the universe to overcome.

Related Posts

How Many Types of Natural Disasters

How Many Types of Natural Disasters Exist?


Pluton: A Dwarf Planet Beyond Neptune

Common Myths and Misconceptions

Common Myths and Misconceptions: Debunking False Beliefs

Is There a Parallel Universe

Is There a Parallel Universe? Exploring the Possibility of Multiple Realities

Terms and Conditions

A ship with a ring around it and stars stretched to lines around it.

Warp drives: Physicists give chances of faster-than -light space travel a boost

mind can travel faster than light

Associate Professor of Physics, Oklahoma State University

Disclosure statement

Mario Borunda 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.

Oklahoma State University provides funding as a member of The Conversation US.

View all partners

The closest star to Earth is Proxima Centauri. It is about 4.25 light-years away, or about 25 trillion miles (40 trillion km). The fastest ever spacecraft, the now- in-space Parker Solar Probe will reach a top speed of 450,000 mph. It would take just 20 seconds to go from Los Angeles to New York City at that speed, but it would take the solar probe about 6,633 years to reach Earth’s nearest neighboring solar system.

If humanity ever wants to travel easily between stars, people will need to go faster than light. But so far, faster-than-light travel is possible only in science fiction.

In Issac Asimov’s Foundation series , humanity can travel from planet to planet, star to star or across the universe using jump drives. As a kid, I read as many of those stories as I could get my hands on. I am now a theoretical physicist and study nanotechnology, but I am still fascinated by the ways humanity could one day travel in space.

Some characters – like the astronauts in the movies “Interstellar” and “Thor” – use wormholes to travel between solar systems in seconds. Another approach – familiar to “Star Trek” fans – is warp drive technology. Warp drives are theoretically possible if still far-fetched technology. Two recent papers made headlines in March when researchers claimed to have overcome one of the many challenges that stand between the theory of warp drives and reality.

But how do these theoretical warp drives really work? And will humans be making the jump to warp speed anytime soon?

A circle on a flat blue plane with the surface dipping down in front and rising up behind.

Compression and expansion

Physicists’ current understanding of spacetime comes from Albert Einstein’s theory of General Relativity . General Relativity states that space and time are fused and that nothing can travel faster than the speed of light. General relativity also describes how mass and energy warp spacetime – hefty objects like stars and black holes curve spacetime around them. This curvature is what you feel as gravity and why many spacefaring heroes worry about “getting stuck in” or “falling into” a gravity well. Early science fiction writers John Campbell and Asimov saw this warping as a way to skirt the speed limit.

What if a starship could compress space in front of it while expanding spacetime behind it? “Star Trek” took this idea and named it the warp drive.

In 1994, Miguel Alcubierre, a Mexican theoretical physicist, showed that compressing spacetime in front of the spaceship while expanding it behind was mathematically possible within the laws of General Relativity . So, what does that mean? Imagine the distance between two points is 10 meters (33 feet). If you are standing at point A and can travel one meter per second, it would take 10 seconds to get to point B. However, let’s say you could somehow compress the space between you and point B so that the interval is now just one meter. Then, moving through spacetime at your maximum speed of one meter per second, you would be able to reach point B in about one second. In theory, this approach does not contradict the laws of relativity since you are not moving faster than light in the space around you. Alcubierre showed that the warp drive from “Star Trek” was in fact theoretically possible.

Proxima Centauri here we come, right? Unfortunately, Alcubierre’s method of compressing spacetime had one problem: it requires negative energy or negative mass.

A 2–dimensional diagram showing how matter warps spacetime

A negative energy problem

Alcubierre’s warp drive would work by creating a bubble of flat spacetime around the spaceship and curving spacetime around that bubble to reduce distances. The warp drive would require either negative mass – a theorized type of matter – or a ring of negative energy density to work. Physicists have never observed negative mass, so that leaves negative energy as the only option.

To create negative energy, a warp drive would use a huge amount of mass to create an imbalance between particles and antiparticles. For example, if an electron and an antielectron appear near the warp drive, one of the particles would get trapped by the mass and this results in an imbalance. This imbalance results in negative energy density. Alcubierre’s warp drive would use this negative energy to create the spacetime bubble.

But for a warp drive to generate enough negative energy, you would need a lot of matter. Alcubierre estimated that a warp drive with a 100-meter bubble would require the mass of the entire visible universe .

In 1999, physicist Chris Van Den Broeck showed that expanding the volume inside the bubble but keeping the surface area constant would reduce the energy requirements significantly , to just about the mass of the sun. A significant improvement, but still far beyond all practical possibilities.

A sci-fi future?

Two recent papers – one by Alexey Bobrick and Gianni Martire and another by Erik Lentz – provide solutions that seem to bring warp drives closer to reality.

Bobrick and Martire realized that by modifying spacetime within the bubble in a certain way, they could remove the need to use negative energy. This solution, though, does not produce a warp drive that can go faster than light.

[ Over 100,000 readers rely on The Conversation’s newsletter to understand the world. Sign up today .]

Independently, Lentz also proposed a solution that does not require negative energy. He used a different geometric approach to solve the equations of General Relativity, and by doing so, he found that a warp drive wouldn’t need to use negative energy. Lentz’s solution would allow the bubble to travel faster than the speed of light.

It is essential to point out that these exciting developments are mathematical models. As a physicist, I won’t fully trust models until we have experimental proof. Yet, the science of warp drives is coming into view. As a science fiction fan, I welcome all this innovative thinking. In the words of Captain Picard , things are only impossible until they are not.

  • General Relativity
  • Theoretical physics
  • Interstellar
  • Speed of light
  • Albert Einstein

mind can travel faster than light

Lecturer / Senior Lecturer - Marketing

mind can travel faster than light

Communications and Engagement Officer, Corporate Finance Property and Sustainability

mind can travel faster than light

Assistant Editor - 1 year cadetship

mind can travel faster than light

Executive Dean, Faculty of Health

mind can travel faster than light

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

Universe Today

Universe Today

Space and astronomy news

mind can travel faster than light

How Can Space Travel Faster Than The Speed Of Light?

Cosmologists are intellectual time travelers. Looking back over billions of years, these scientists are able to trace the evolution of our Universe in astonishing detail. 13.8 billion years ago, the Big Bang occurred. Fractions of a second later, the fledgling Universe expanded exponentially during an incredibly brief period of time called inflation. Over the ensuing eons, our cosmos has grown to such an enormous size that we can no longer see the other side of it.

But how can this be? If light’s velocity marks a cosmic speed limit, how can there possibly be regions of spacetime whose photons are forever out of our reach? And even if there are, how do we know that they exist at all?

The Expanding Universe

Like everything else in physics, our Universe strives to exist in the lowest possible energy state possible. But around 10 -36 seconds after the Big Bang, inflationary cosmologists believe that the cosmos found itself resting instead at a “false vacuum energy” – a low-point that wasn’t really a low-point. Seeking the true nadir of vacuum energy, over a minute fraction of a moment, the Universe is thought to have ballooned by a factor of 10 50 .

Since that time, our Universe has continued to expand, but at a much slower pace. We see evidence of this expansion in the light from distant objects. As photons emitted by a star or galaxy propagate across the Universe, the stretching of space causes them to lose energy. Once the photons reach us, their wavelengths have been redshifted in accordance with the distance they have traveled.

Two sources of redshift: Doppler and cosmological expansion; modeled after Koupelis & Kuhn. Credit: Brews Ohare.

This is why cosmologists speak of redshift as a function of distance in both space and time. The light from these distant objects has been traveling for so long that, when we finally see it, we are seeing the objects as they were billions of years ago.

The Hubble Volume

Redshifted light allows us to see objects like galaxies as they existed in the distant past; but we cannot see all events that occurred in our Universe during its history. Because our cosmos is expanding, the light from some objects is simply too far away for us ever to see.

The physics of that boundary rely, in part, on a chunk of surrounding spacetime called the Hubble volume. Here on Earth, we define the Hubble volume by measuring something called the Hubble parameter (H 0 ), a value that relates the apparent recession speed of distant objects to their redshift. It was first calculated in 1929, when Edwin Hubble discovered that faraway galaxies appeared to be moving away from us at a rate that was proportional to the redshift of their light.

Fit of redshift velocities to Hubble's law. Credit: Brews Ohare

Dividing the speed of light by H 0 , we get the Hubble volume. This spherical bubble encloses a region where all objects move away from a central observer at speeds less than the speed of light. Correspondingly, all objects outside of the Hubble volume move away from the center  faster than the speed of light.

Yes, “faster than the speed of light.” How is this possible?

The Magic of Relativity

The answer has to do with the difference between special relativity and general relativity. Special relativity requires what is called an “inertial reference frame” – more simply, a backdrop. According to this theory, the speed of light is the same when compared in all inertial reference frames. Whether an observer is sitting still on a park bench on planet Earth or zooming past Neptune in a futuristic high-velocity rocketship, the speed of light is always the same. A photon always travels away from the observer at 300,000,000 meters per second, and he or she will never catch up.

General relativity, however, describes the fabric of spacetime itself. In this theory, there is no inertial reference frame. Spacetime is not expanding with respect to anything outside of itself, so the the speed of light as a limit on its velocity doesn’t apply. Yes, galaxies outside of our Hubble sphere are receding from us faster than the speed of light. But the galaxies themselves aren’t breaking any cosmic speed limits. To an observer within one of those galaxies, nothing violates special relativity at all. It is the space in between us and those galaxies that is rapidly proliferating and stretching exponentially.

The Observable Universe

Now for the next bombshell: The Hubble volume is not the same thing as the observable Universe.

To understand this, consider that as the Universe gets older, distant light has more time to reach our detectors here on Earth. We can see objects that have accelerated beyond our current Hubble volume because the light we see today was emitted when they were within it.

Strictly speaking, our observable Universe coincides with something called the particle horizon . The particle horizon marks the distance to the farthest light that we can possibly see at this moment in time – photons that have had enough time to either remain within, or catch up to, our gently expanding Hubble sphere.

And just what is this distance? A little more than 46 billion light years in every direction – giving our observable Universe a diameter of approximately 93 billion light years, or more than 500 billion trillion miles.

The observable - or inferrable universe. This may just be a small component of the whole ball game.

(A quick note: the particle horizon is not the same thing as the cosmological event horizon . The particle horizon encompasses all the events in the past that we can currently see. The cosmological event horizon, on the other hand, defines a distance within which a future observer will be able to see the then-ancient light our little corner of spacetime is emitting today.

In other words, the particle horizon deals with the distance to past objects whose ancient light that we can see today; the cosmological event horizon deals with the distance that our present-day light that will be able to travel as faraway regions of the Universe accelerate away from us.)

Dark Energy

Thanks to the expansion of the Universe, there are regions of the cosmos that we will never see, even if we could wait an infinite amount of time for their light to reach us. But what about those areas just beyond the reaches of our present-day Hubble volume? If that sphere is also expanding, will we ever be able to see those boundary objects?

This depends on which region is expanding faster – the Hubble volume or the parts of the Universe just outside of it. And the answer to that question depends on two things: 1) whether H 0 is increasing or decreasing, and 2) whether the Universe is accelerating or decelerating. These two rates are intimately related, but they are not the same.

In fact, cosmologists believe that we are actually living at a time when H 0  is decreasing; but because of dark energy, the velocity of the Universe’s expansion is increasing.

That may sound counterintuitive, but as long as H 0  decreases at a slower rate than that at which the Universe’s expansion velocity is increasing, the overall movement of galaxies away from us still occurs at an accelerated pace. And at this moment in time, cosmologists believe that the Universe’s expansion will outpace the more modest growth of the Hubble volume.

So even though our Hubble volume is expanding, the influence of dark energy appears to provide a hard limit to the ever-increasing observable Universe.

Our Earthly Limitations

cosmology tapestry

Cosmologists seem to have a good handle on deep questions like what our observable Universe will someday look like and how the expansion of the cosmos will change. But ultimately, scientists can only theorize the answers to questions about the future based on their present-day understanding of the Universe. Cosmological timescales are so unimaginably long that it is impossible to say much of anything concrete about how the Universe will behave in the future. Today’s models fit the current data remarkably well, but the truth is that none of us will live long enough to see whether the predictions truly match all of the outcomes.

Disappointing? Sure. But totally worth the effort to help our puny brains consider such mind-bloggling science – a reality that, as usual, is just plain stranger than fiction.

Share this:

  • Click to share on Facebook (Opens in new window)
  • Click to share on Twitter (Opens in new window)
  • Click to share on Reddit (Opens in new window)

30 Replies to “How Can Space Travel Faster Than The Speed Of Light?”

Vanessa, you’ve managed to confuse me, but after reading further on, I found that you’ve made yourself clear. Your article describes some very interesting terms – I guess people could discuss them for hours 🙂 Thanks!

One thing I’ve never understood about about this sort of thing, when cosmologists talk about the inflationary period and the universe expanding, what is the universe expanding into? I think this metaphor explains the math somewhat, but ultimately it doesn’t do the concepts justice.

Zogg from Betelgeuse has been mentioned on UT before: http://www.universetoday.com/103790/zogg-from-betelgeuse-explains-why-the-universe-has-no-edge/

Parts 1 & 2 of his episodes on the topology of the universe explain this and other thorny cosmological concepts. You’ll have to decide which concept is hardest to deal with — the concept of an infinite universe with no edges in Pt. 1, or the Pt. 2 announcement that “It doesn’t expand into anything; it just expands,” to name two — but he uses some pretty clear imagery & examples to explain them.

FTR, not saying he’s necessarily “absolutely right” , just saying the concepts are clearly and reasonably explained.

To address your statement: “. . .but the truth is that none of us will live long enough to see whether the predictions truly match all of the outcomes.”

“Everything he has made pretty in its time. Even time indefinite he has put in their heart, that mankind may never find out the work that the [true] God has made from the start to the finish.” – Ecclesiastes 3:11. Depending on the translation, the term “everlasting life” in connection what righteous humans will enjoy in the near future, appears about 140 in the Bible. The term “live forever” appears about 39 times. And the Bible states that the Earth was created and will exist for all eternity as the home of humankind.

The Bible specifically indicates that mankind was created to live forever on this earth, with perfect spiritual, moral, emotional, mental and physical health; in paradise conditions. And it is for this reason that our Creator endowed us humans with the concept of eternity …because we were created to live forever. And the Bible tells us how that processes was interrupted, and how it will be restored.

So then, yes many will live long enough to see “whether the predictions truly match all of the outcomes.” Not only that they will live to continue adding to current knowledge, as many features of creation that are know beyond our grasp, will be unfold before us throughout all eternity.

The Bible was wrote by man at a time when eternity was an unfathomable long time. Now we know the Earth is going to end. And even if it somehow survives the Sun’s expansion, is will be an uninhabitable husk. I think God showed how long the earth was to last. But it was an incomprehensible long time so the term of eternity aptly applied. Just as we now know the world is not flat, we know eternity is not in the cards for us on Earth. That does not prevent man from moving on in the cosmos. It just means that Earth won’t be our home for all of Eternity. It will be man’s birth place for all of Eternity though. That is always going to be true.

I think that the sun has a few billion years of life in it. I think that We have maybe a few. The way we are treating the earth and each other gives us a great minus. I won’t to think that another poster would be wright, but I really have my doubts. I know God, but I don’t know the mind or will of God.

Good point about the eventual end of the Earth billions of years from now when the Sun dies out. But if you believe God can create a universe then it’s very possible he can save a planet for eternity. 🙂 Who knows how that will be explained with science but it’s certainly not without possibility for an all powerful God!

But you’re forgetting that the Elder Gods (Cthulhu, Hastur, Yog-Sothoth, Shub-Nigurath, etc.), as described in H.P. Lovecraft’s works, will soon destroy the Earth while driving humanity into the darkest pits of madness. So clearly we won’t live long enough to observe the results.

You really should learn about more than just one myth!

To be utterly fair, if M_L is using the Bible to come up with the world view described above, then he/she hasn’t even learned his/her OWN ‘myth’ correctly(*), so I wouldn’t put high odds on knowing too many others with any accuracy. As always, I could be wrong, however….

*(Ps 102:25-27 and Lk 21:33, et al., for those who want references.)

Couldn’t find a “Thumbs Up” so I made one: (hopefully, it works because you truly deserve a TU!)

………..__ ………./ (| ……..(___ | ……. |.._ |______ ..(____) ` | (____) | .(____) | ..(___)_.__|_____

The stars are almost right…… 🙂

This is a science website… We deal in facts here.

Wow, I love how you wove passages and meaning from the Bible into the cosmology discussion. It just goes to show that the two topics are infinitely interesting and provide multiple angles on the human condition of creativity. Thanks for sharing.

I meant to say “curiousity” not creativity. It’s late, sorry.

Pretty well explained article but I have to point out that Hubble was not the discoverer of galactic recession, or redshift. Vesto Slipher discovered that in 1912, at Lowell Observatory, well before you credit Hubble in 1929. Slipher was also the first to observe galactic rotation. Hubble was a very good self publicist and good at using the results of others (e.g. expanding universe) to his own ends. Brilliant in his own way but a bit of a b…… 🙂

You gotta admit, though that, “The Slipher Space Telescope” doesn’t quite roll of the tongue… hehehe 😉

Einstein himself had problems with his theory of relativity because of the “spooky actions at a distance”. He realized that this most certainly indicated that C was not Vmax. This of course would invalidate the theory of relativity. He died while working on this problem. It is becoming abundantly clear that Tesla was much more correct when he proposed that the speed of electrons was 1.67 x C. For this reason he referred to the theory of relativity was like ” a beggar in a purple robe”. Many brilliant physicists have followed Einstein down the wrong road. This is the reason that the standard model for cosmology being in such trouble. I believe we are now obtaining radio telescope data that will invalidate the theories of black holes, neutron stars, dark matter and stellar nuclear fusion. These tenets have never been observed or experimentally confirmed. Even more important is that they require the known laws of physics and chemistry to break down. They also make no sense whatsoever. Halton Arp’s (Max Planck Inst. and a student of Edmund Hubble) work on red shift will invalidate the theory of the big bang. Chandra findings are clearly showing that red shift is an intrinsic function of AGE, not distance or velocity. His book “Seeing Red” caused Carl Sagan to say that the findings were inconsistent with a “Big Bang”. There is a growing body of evidence that suggest electromagnetic forces are the driving force for planet, star and galaxy formation. Anthony Peratt’s work at Los Alamos convincingly showed spiral galaxy formation from plasma. More importantly these formations had the necessary velocities so that black holes and dark matter/energy were not required. Okam’s Razor should be considered when comparing electromagnetic versus gravitational theories. The concept of nuclear fusion within the sun is in big trouble. They have found insufficient conduction velocities to sustain this theory. The recent NASA missions to the sun have also revealed far greater complexity of the sun’s and the earth’s electromagnetic fields with significant interactions. Donald Scott ( The Electric Sky) addressed NASA at the Goddard Engineering Colloquia in 2009. His talk was well received and is worth hearing. It is on U Tube. He made a convincing argument that the door should be opened to further evaluate the electric models of cosmology. Quietly, NASA missions are doing this and appear to be confirming the basic tenets of these models.

Just. Stop…. You’ve made your point here over and over and over and over and over and over and over again in relentless, droning rants. OK. We get it: You know more than thousands of the best and brightest minds over the past century cumlatively do in the field of astrophysics and have successfully exposed them all for wasting their lives intentionally trying (for whatever reason) to prove a theory that OBVIOUSLY doesn’t work. You have reams of data supporting this, but for whatever reason, the people that have collected this data refuse to acknowledge any of it to the end you propose. You’re a genius and the rest of the Astrophysics (and Particle, for that matter, pun intended) communities are prideful and ignorant morons. You win. Now why don’t you just leave it at that and shut. up?

OK, I’m just going to stop reading comments on this site in articles that might have your attention so I won’t keep getting sucked into replying to you. It’s not affording me the opportunity anymore to delete it or I would, I’m sorry for insulting you and I feel like a dick. Have your opinion and I’ll have mine.

Its Ok Jeffrey – btraymd – please understand we are not ganging up on you and we commenters here have no alterior motive.. Its just that we would be excited if you could please site (contemporary) peer reviewed papers or a (contemporary) confirmed experiment or two .. some math formulas we could run inside a computer.. anything but this unsubstantiated conjecture dressed up as theory you are pushing.. You can push EU “theory” on your own youtube videos but you should expect healthy scepticism to your claims here.. Its Ok Jeffery – take a deep breath…

Uh, what? Neutron stars most definitely have been observed. Where do you get this nonsense from?

Not sure why I’m replying. Experience has shown that you are very keen to make portentous-sounding but vague and contentless claims, but you flee from any actual debate about those claims. I never did get a response to my posts showing that all of the Electric Universe predictions regarding comets Tempel 1 and Churyumov-Gerasimenko turned out to be spectacularly wrong.

If the maximum speed of an electron is 1.67c as you claim, how come nobody has been able to accelerate one to more than 1.0c?

If there is no nuclear fusion in the Sun, where are all the neutrinos coming from? Only nuclear processes can produce neutrinos. Electromagnetism cannot. So how is the Sun producing neutrinos?

Relativity speaking, Einstein’s Special Relativity is not quite right. http://brokenelevator.weebly.com/ The site presents the information at a High School level.

It’s been proven through observations many many times and never disproven once.

Vanessa, It seems your post is confusing to readers. I think that is because your ideas need more and better explanations. For example, you cite some opinions as if they were fact when you state that “…inflationary cosmologists believe…,” as if all of them believe the cosmos “rested” during the Big Bang (BB) at a ‘false vacuum energy (level).’ How could that happen unless there was no BB at all, and you do not explain just what such energy was. You do not cite your source of the light-shift chart for us to review. The chart requires that there is such a thing as “tired light” after all, or something similar to it, although that idea was long ago discarded. You claim that as space expands, light waves are stretched out to create the redshift effect. That requires light-wave frequency changes, but you do not explain what would cause that. Doppler shifts occur when we or the em waves move away or toward us. It is direction of motion that causes redshifts, not the expansion of space. But please feel free to post how you arrived at your conclusion. Without a source, we each own the ideas we make up. You sat that in GR, space-time (S-T) is not expanding. That is because the S-T Continuum does not physically exist! It is a math tool Einstein invented to prove his theories with math! Math constructs can only exist in our minds. Please know this is not a flame. You are no different than all of us in saying that it is space that is expanding. That is because matter is not moving apart as it moves away at higher speeds. But that leaves the question, why then is space not expanding locally? Some say it is due to the idea that expansion of space occurs faster the farther away from us, as seen in the good ‘ol bakin’ raisin dough model that has served us so well. To me, that sounds too much as if we are the center of the U, however. Everyone here seems to be afraid to respond to my ideas, but I hope you are not. Conformity is a killing field of ideas, yet the faculty we have to create them is mankind’s highest reason for being. In physics, there is no reason to fear new ideas.

The newest data from Chandra and Planck have revealed findings that put into serious doubt the theories of expansion and the big bang. They have identified quasars which are physically connected to galaxies as if being produced by the galaxies. What’s interesting is that the red shifts are very different. This provides solid evidence for the work of Halton Arp (a student of Edmund Hubble, working at the Max Planck Institute in Germany). In his book “Seeing Red’ he made a convincing case that red shift is an intrinsic function of age, not distance or velocity. This would invalidate the data used to propose both the big bang and expansion. Maybe this is why neither concept makes much sense and cannot be verified.

Good comment.

I replied and re-read your comment and had to head scratch.. AGNs and quasars have been an enigma since Arps time.. but found this on the hubble site – it might help propose an explanation..


” Today most astronomers believe that quasars, radio galaxies and the centres of so-called active galaxies just are different views of more or less the same phenomenon: a black hole with energetic jets beaming out from two sides. When the beam is directed towards us we see the bright lighthouse of a quasar. When the orientation of the system is different we observe it as an active galaxy or a radio galaxy. This ‘unified model’ has gained considerable support through a number of Hubble observational programs. The simplistic early ideas have however been replaced by a more complex view of this phenomenon – a view that will continue to evolve in the years to come.

I dont want my post above to come across as dismissive. Your arguments against conventional BB cosmology have some basis in logic.. As for the EU hypothesis (i am being polite giving it that label). You have not yet made any points that argue in its favour to me.. I will still listen with an open mind. In future if you want to dismantle mainstream theory and propose an alternate theory, please supply valid positive arguments citing contemporary observation and experiments and I will have more time to listen and comment..

Wow, according to the math it looks like light from the Big Bang has only covered 15% of the total diameter of the universe, meaning that 85% of the universe hasn’t even been seen yet. Is that right? Incredible!

To the author Vanessa,

I know this article has been up a while and this comment is a long way down but I am curious to get your thoughts / views if you are aware of Einsteins unpublished 1931 theory of Dynamic Equilibrium.

As mentioned here Lemaitre and Einstein independtly predicted the boundary of the universe:

http://adsabs.harvard.edu/abs/2015AAS …22521504S

For anyone curious, this youtube video discusses the theory of Dynamic Equillibrium, a theory authored independently by both Lemaitre and Einstein


“The redshift” is due to two simple things (and I have no idea how many complicated ones). First, movement — the old classical Doppler Effect. Second, the gravity well. What? OK, see this: http:/downshifting.weebly.com . When light travels out of a star (gravity well) it gets redshifted. Sort of like when you throw a ball up, it gets more gravitational potential energy but you lose kenetic energy. Light loses kenetic energy, not by slowing, but by redening. These are very simple concpets that I think that anyone can understand.

Comments are closed.


  1. What is the speed of thought?

    First, some thoughts on thought. To quantify the speed of anything, one needs to identify its beginning and end. For our purposes, a "thought" will be defined as the mental activities engaged ...

  2. Is our mind faster than light?

    5. Here is what I have been told by some Thai followers: The sun's light takes 8 minutes to reach the Earth, but our mind can think of the sun or even of distant stars instantly. That is to say, our mind is faster than the speed of light. They claim science is a subset of Buddhism.

  3. It feels instantaneous, but how long does it really take to think a

    In the human context, the signals carried by the large-diameter, myelinated neurons that link the spinal cord to the muscles can travel at speeds ranging from 70-120 meters per second (m/s) (156 ...

  4. The Brain: What Is the Speed of Thought?

    Using a fast code helps speed up thought, but to a large extent the brain—like a telegraph network—really depends on efficient pathways. Impulses from the retinas, for instance, have to travel up the optic nerve to the thalamus, which relays the signals to the visual cortex in the back of the brain. Then they ripple forward to other brain ...

  5. What is the speed of thought?

    What is the speed of thought? - BBC Science Focus Magazine

  6. Will Humans Ever Go Faster Than Light?

    Einstein's special theory of relativity governs our understanding of both the flow of time and the speed at which objects can move. In special relativity, the speed of light is the ultimate speed limit to the universe. Nothing can travel faster than it. Every single moving object in the universe is constrained by that fundamental limit.

  7. The Ultimate Paradox: Travelling Faster Than Light ...

    Yet, in 1994, a Mexican scientist said that travelling faster than light was possible while Einstein's theories would still hold true. That's the absolute paradox. Humans can travel faster than a certain limit without disqualifying the theory that says that humans cannot travel faster than this limit.

  8. Can anything travel faster than the speed of light?

    So, according to de Rham, the only thing capable of traveling faster than the speed of light is, somewhat paradoxically, light itself, though only when not in the vacuum of space. Of note ...

  9. Time Slips, the Multiverse, and You

    The universe has a "speed limit" called the speed of light, faster than which nothing in our universe can travel. The multiverse theory explains how it could be possible for people to have ...

  10. Research Shows Faster-Than-Light Warp Speed Is (Probably) Possible

    Symmetry is a physics concept that goes all the way back to Galileo's time. The secret to faster-than-light physics could be to double down on the number of dimensions. Specifically, the ...

  11. 4 Things That Currently Break the Speed of Light Barrier

    1. The Big Bang itself expanded much faster than the speed of light. But this only means that "nothing can go faster than light.". Since nothing is just empty space or vacuum, it can expand ...

  12. The real reason you can't go faster than light speed

    The speed limit is a harsh reality. The reason that it is hard to travel through space at the speed of light is that you must push the object out of moving in the time direction to moving more in ...

  13. Why you can't travel at the speed of light

    This explains why nothing can travel faster than light - at or near light speed, any extra energy you put into an object does not make it move faster but just increases its mass. Mass and energy ...

  14. What If You Traveled Faster Than the Speed of Light?

    In other words, the faster an object moves, the greater its mass. This only becomes noticeable when an object moves really quickly. If it moves at 10 percent the speed of light, for example, its mass will only be 0.5 percent more than normal. But if it moves at 90 percent the speed of light, its mass will double [source: LBL.gov ].

  15. Mass misconception: Why we can't outpace light speed

    Einstein's theory of relativity sets a cosmic speed limit: nothing can travel faster than the speed of light, posing challenges for space exploration. A widespread but incorrect explanation ...

  16. These 4 Cosmic Phenomena Travel Faster Than The Speed of Light

    The closest humankind has ever come to reaching the speed of light is inside of powerful particle accelerators like the Large Hadron Collider and the Tevatron. These colossal machines accelerate subatomic particles to more than 99.99 percent the speed of light, but as Physics Nobel laureate David Gross explains, these particles will never reach ...

  17. Why We Can't Travel Faster than the Speed of Light

    This means that nothing can travel faster than the speed of light. The theory of relativity has been tested and verified countless times, and experiments have confirmed its predictions. One of the key concepts of relativity is that space and time are not separate entities but are instead intertwined in a four-dimensional fabric called spacetime.

  18. Faster-Than-Light Travel Is Possible Within Einstein's Physics

    This is an area that attracts plenty of bright ideas, each offering a different approach to solving the puzzle of faster-than-light travel: achieving a means of sending something across space at superluminal speeds.. Hypothetical travel times to Proxima Centauri, the nearest-known star to the Sun. (E. Lentz) There are some problems with this notion, however.

  19. Neutrinos Travel Faster Than Light, According to One Experiment

    They found that, on average, the neutrinos made the 730-kilometer, 2.43-millisecond trip roughly 60 nanoseconds faster than expected if they were traveling at light speed. "It's a straightforward time-of-flight measurement," says Antonio Ereditato, a physicist at the University of Bern and spokesperson for the 160-member OPERA collaboration.

  20. Warp drives: Physicists give chances of faster-than-light space travel

    The fastest ever spacecraft, the now- in-space Parker Solar Probe will reach a top speed of 450,000 mph. It would take just 20 seconds to go from Los Angeles to New York City at that speed, but it ...

  21. How Can Space Travel Faster Than The Speed Of Light?

    Credit: Brews Ohare. Dividing the speed of light by H 0, we get the Hubble volume. This spherical bubble encloses a region where all objects move away from a central observer at speeds less than ...