technology to travel at the speed of light

NASA engine capable of travelling at nearly the speed of light detailed in new report

As more countries join the race to explore space, a NASA scientist has revealed a new propulsion method that could give his agency the edge.

‘Devil comet’ to wow Aussies this weekend

‘Moon is made of gas’: Embarrassing fail

TV station accidentally airs man’s testicles

A NASA scientist has cooked up plans for a bonkers new rocket engine that can reach close to the speed of light — without using any fuel.

Travelling at such speeds, the theoretical machine could carry astronauts to Mars in less than 13 minutes, or to the Moon in just over a second.

However, the real purpose of the so-called “helical engine” would be to travel to distant stars far quicker than any existing tech, according to NASA engineer Dr David Burns.

Dr Burns, from NASA’s Marshall Space Flight Centre in Alabama, unveiled the idea in a head-spinning paper posted to NASA’s website.

“This in-space engine could be used for long-term satellite station-keeping without refuelling,” Dr Burns writes in his paper .

“It could also propel spacecraft across interstellar distances, reaching close to the speed of light.”

RELATED: Humans ‘not prepared’ for alien bombshell

Travelling at these speeds, light would struggle to keep up with you, warping your vision in bizarre ways.

Everything behind you would appear black, and time would appear to stop altogether, with clocks slowing down to a crawl and planets seemingly ceasing to spin.

Dr Burns’ mad idea is revolutionary because it does away with rocket fuel altogether.

Today’s rockets, like those built by NASA and SpaceX, would need tonnes of propellants like liquid hydrogen to carry people to Mars and beyond.

The problem is, the more fuel you stick on the craft, the heavier it is. Modern propellant tanks are far too bulky to take on interstellar flights.

The helical engine gets around this using hi-tech particle accelerators like those found in Europe’s Large Hadron Collider.

Tiny particles are fired at high speed using electromagnets, recycled back around the engine, and fired again.

Using a loophole in the laws of physics, the engine could theoretically reach speeds of around 297 million metres per second, according to Dr Burns.

The contraption is just a concept for now, and it’s not clear if it would actually work.

“If someone says it doesn’t work, I’ll be the first to say, it was worth a shot,” Dr Burns told New Scientist .

“You have to be prepared to be embarrassed. It is very difficult to invent something that is new under the sun and actually works.”

In its simplest terms, the engine works by taking advantage of how mass changes at the speed of light.

In his paper, Dr Burns provides a concept to break this down that describes a ring inside a box, attached to each end by a spring.

When the ring is sprung in one direction, the box recoils in the other, as is described by Newton’s laws of motion: Every action must have an equal and opposite reaction.

“When the ring reaches the end of the box, it will bounce backwards, and the box’s recoil direction will switch too,” New Scientist explains.

However, if the box and the ring are travelling at the speed of light, things work a little differently.

At such speeds, according to Albert Einstein’s theory of relativity, as the ring approaches the end of the box it will increase in mass.

This means it will hit harder when it reaches the end of the box, resulting in forward momentum.

The engine itself will achieve a similar feat using a particle accelerator and ion particles, but that’s the general gist.

RELATED: Space race as HQ falls behind schedule

“Chemical, nuclear and electric propulsion systems produce thrust by accelerating and expelling propellants,” Dr Burns writes in his paper.

“Deep space travel is often a trade-off between thrust and large propellant storage tanks that eventually limit performance.

“The objective of this paper is to introduce and examine a unique engine that uses a closed-cycle propellant.”

The design is capable of producing a thrust up to 99 per cent the speed of light without breaking Einstein’s theory of relativity, according to Dr Burns.

However, the plan does breach Newton’s law of motion — violating the laws of physics.

That’s not the only thing holding the helical engine back: Dr Burns reckoned it would have to be 198 metres long and 12 metres wide to work.

The gizmo would also only operate effectively in the frictionless environment of deep space.

It may sound like a harebrained scheme, but engine concepts that do away with rocket fuel have been proposed before.

They include the EM drive, a machine that could theoretically generate rocket thrust using rays of light. The idea was later proved impossible.

“I know that it risks being right up there with the EM drive and cold fusion,” Dr Burns told New Scientist .

This article originally appeared on The Sun and was reproduced with permission

Add your comment to this story

To join the conversation, please log in. Don't have an account? Register

Join the conversation, you are commenting as Logout

A spectacular comet will soon briefly come into view for Australians before disappearing again for another 71 years.

A politician has gone viral for a very unusual act during the recent eclipse.

A news outlet has been ridiculed after it aired a man’s testicles while presenting viewer-submitted footage of Monday’s solar eclipse.

Scientists Believe Light Speed Travel Is Possible. Here’s How.

A functioning warp drive would allow humans to reach the far ends of the cosmos in the blink of an eye.

White and his team in LSI’s Houston laboratory were conducting research for the Defense Advanced Research Projects Agency, or DARPA, and had set up these particular experiments to study the energy densities within Casimir cavities, the mysterious spaces between microscopic metal plates in a vacuum. The data plot indicated areas of diminished energy between the plates, which caused them to push toward each other as if trying to fill the void. This is known as negative vacuum energy density, a phenomenon in quantum mechanics called, appropriately enough, the Casimir effect . It’s something that’s helping scientists understand the soupy physics of microscale structures, which some researchers hope can be applied to energy applications that are more practical, such as circuits and electromechanical systems.

But White noticed that the pattern of negative vacuum energy between the plates and around tiny cylindrical columns that they’d inserted in the space looked familiar. It precisely echoed the energy pattern generated by a type of exotic matter that some physicists believe could unlock high-speed interstellar travel. “We then looked, mathematically, at what happens if we placed a one-micron sphere inside of a four-micron cylinder under the same conditions, and found that this kind of structure could generate a little nanoscale warp bubble encapsulating that central region,” White explains.

That’s right—a warp bubble. The essential component of a heretofore fictional warp drive that has for decades been the obsession of physicists, engineers, and sci-fi fans. Warp drive, of course, is the stuff of Star Trek legend, a device enclosed within a spacecraft that gives the mortals aboard the ability to rip around the cosmos at superhuman speed. To the lay sci-fi fan, it’s a “black box”—a convenient, completely made-up workaround to avoid the harsh realities of interstellar travel. However, after decades of speculation, research, and experimentation, scientists believe a warp drive could actually work.

To emphasize: White didn’t actually make a warp bubble. But the data from his study led to an aha moment: For the first time, a buildable warp bubble showed promise of success.

Warp technology’s core science is surprisingly sound. Though the specific mechanics of an actual device haven’t been fully unpacked, the math points toward feasibility. In short, a real-life warp drive would use massive amounts of energy, which can come in the form of mass, to create enough gravitational pull to distort spacetime in a controlled fashion, allowing a ship to speed along inside a self-generated bubble that itself is able to travel at essentially any speed. Warp drives popped up in fiction intermittently for several decades before Star Trek creator Gene Roddenberry plugged one into the USS Enterprise in 1966. But Miguel Alcubierre, PhD, a Mexican theoretical physicist and professed Star Trek enthusiast, gave the idea real-world legs when he released a paper in 1994 speculating that such a drive was mathematically possible. It was the first serious treatment of a warp drive’s feasibility, and it made headlines around the world. His breakthrough inspired more scientists to nudge the theoretical aspects of warp drive toward concrete, practical applications.

“I proposed a ‘geometry’ for space that would allow faster-than-light travel as seen from far away, essentially expanding space behind the object we want to move and contracting it in front,” Alcubierre says. “This forms a ‘bubble’ of distorted space, inside of which an object—a spaceship, say—could reside.”

Physicists tend to speak in relative terms. By injecting the sly qualifier “as seen from far away,” Alcubierre might sound like he’s describing the galactic equivalent of an optical illusion —an effect perhaps similar to driving past a truck going the opposite direction on the highway when you’re both going 60 miles an hour. Sure feels like a buck-twenty, doesn’t it? But the A-to-B speed is real; the warp effect simply shortens the literal distance between two points. You’re not, strictly speaking, moving faster than light. Inside the bubble, all appears relatively normal, and light moves faster than you are, as it should. Outside the bubble, however, you’re haulin’ the mail.

.css-2l0eat{font-family:UnitedSans,UnitedSans-roboto,UnitedSans-local,Helvetica,Arial,Sans-serif;font-size:1.625rem;line-height:1.2;margin:0rem;padding:0.9rem 1rem 1rem;}@media(max-width: 48rem){.css-2l0eat{font-size:1.75rem;line-height:1;}}@media(min-width: 48rem){.css-2l0eat{font-size:1.875rem;line-height:1;}}@media(min-width: 64rem){.css-2l0eat{font-size:2.25rem;line-height:1;}}.css-2l0eat b,.css-2l0eat strong{font-family:inherit;font-weight:bold;}.css-2l0eat em,.css-2l0eat i{font-style:italic;font-family:inherit;} THOUGH THE SPECIFIC MECHANICS OF AN ACTUAL DEVICE HAVEN’T BEEN UNPACKED, THE MATH POINTS TOWARD FEASIBILITY.

Alcubierre’s proposal had solved one of the initial hurdles to achieving warp speeds: The very idea clashes with Einstein’s long-accepted theory of general relativity, which states that nothing can travel faster than the speed of light, but it doesn’t preclude space itself from traveling faster than that. In fact, scientists speculate that the same principles explain the rapid expansion of the universe after the Big Bang .

While concluding that warp speed was indeed possible, Alcubierre also found that it would require an enormous amount of energy to sustain the warp bubble. He theorized that negative energy—the stuff hinted at by White’s experimentation with Casimir cavities—could be a solution. The only problem is that no one has yet proved that negative energy is real. It’s the unobtanium of our spacefaring imaginations, something researchers only believe to exist. In theory, however, this unknown matter may be sufficiently powerful that future warp drive designers could channel it to contract spacetime around it. In conceptual drawings of warp-capable spacecraft , enormous material rings containing this energy source surround a central fuselage. When activated, it warps spacetime around the entire ship. The more intense the warping, the faster the warp travel is achieved.

Of course, it’s not that simple. Physicist José Natário, PhD, a professor at the Instituto Superior Técnico in Lisbon, wrote his own influential paper about the mathematical feasibility of warp drives in 2001. However, he is concerned about practical conundrums, like the amount of energy required. “You need to be able to curve spacetime quite a lot in order to do this,” he says. “We’re talking about something that would be much, much more powerful than the sun.”

Alcubierre is similarly skeptical that his theoretical ideas might ever be used to develop a working warp drive. “In order to have a bubble about 100 meters wide traveling at precisely the speed of light, you would need about 100 times the mass of the planet Jupiter converted into negative energy, which of course sounds absurd,” he says. By that standard, he concludes, a warp drive is very unlikely.

Physicists love a challenge, though. In the 29 years since Alcubierre published his paper, other scientists have wrestled with the implications of the work, providing alternative approaches to generating the energy using more accessible power sources, finding oblique entry points to the problem, and batting ideas back and forth in response to one another’s papers. They use analogies involving trampolines , tablecloths, bowling balls, balloons, conveyor belts, and music to explain the physics.

They even have their own vocabulary. It’s not faster-than-light travel; it’s superluminal travel, thank you. Then there’s nonphysical and physical—a.k.a. the critical distinction between theoretical speculation and something that can actually be engineered. (Pro tip: We’re aiming for physical here, folks.) They do mention Star Trek a lot, but never Star Wars . Even the scruffiest-looking nerf herder knows that the ships in Star Wars use hyperdrive, which consumes fuel, rather than warp drives, which don’t use propulsive technology but instead rely on, well, warping. They’re also vague about details like what passengers would experience, what gravity is like on board since you’re carrying around boatloads of energy, and what would happen if someone, say, jumped out of the ship while warping. (A speculative guess: Nothing good.)

Such research isn’t typically funded by academic institutions or the DARPAs and NASAs of the world, so much of this work occurs in the scientists’ spare time. One such scientist and Star Trek enthusiast is physicist Erik Lentz, PhD. Now a researcher at Pacific Northwest National Laboratory in Richland, Washington, Lentz was doing postdoctoral work at Göttingen University in Germany when, amid the early, isolated days of the pandemic, he mulled the idea of faster-than-light travel. He published a paper in 2021 arguing that warp drives could be generated using positive energy sources instead of the negative energy that Alcubierre’s warp drive seemed to require.

“There are a number of barriers to entry to actually being able to build a warp drive,” Lentz says. “The negative energy was the most obvious, so I tried to break that barrier down.”

He explored a new class of solutions in Einstein’s general relativity while focusing on something called the weak-energy condition, which, he explains, tracks the positivity of energy in spacetime. He hit upon a “soliton solution”—a wave that maintains its shape and moves at a constant velocity—that could both satisfy the energy-level challenge and travel faster than light. Such a warp bubble could travel along using known energy sources, though harnessing those at the levels needed are still far beyond our capabilities. The next step, he notes, may be bringing the energy requirements for a warp drive to within the range of a nuclear fusion reactor.

A fusion-powered device could theoretically travel to and from Proxima Centauri , Earth’s nearest star, in years instead of decades or millennia, and then go faster and faster as power sources improve. Current conventional rocket technology, on the other hand, would take 50,000 years just for a one-way trip—assuming, of course, there was an unlimited fuel supply for those engines.

“IF YOU COLLIDE WITH SOMETHING ON YOUR PATH, IT WOULD ALMOST CERTAINLY BE CATASTROPHIC.”

Like Alcubierre’s original thesis, Lentz’s paper had a seismic impact on the warp drive community, prompting yet another group of scientists to dig into the challenge. Physicist Alexey Bobrick and technology entrepreneur Gianni Martire have been particularly prolific. In 2021, they released a paper theorizing that a class of subliminal warp drives, traveling at just a fraction of light speed, could be developed from current scientific understanding. While that paper essentially argued that it’s perfectly acceptable to walk before you can run, they followed it up with another theory earlier this year that describes how a simulated black hole , created using sound waves and glycerin and tested with a laser beam, could be used to evaluate the levels of gravitational force needed to warp spacetime. The duo coded that breakthrough into a public app that they hope will help more quickly push theoretical ideas to practical ones. Though the team is waiting for the technology to clear a peer review stage before releasing details, the app is essentially a simulator that allows scientists to enter their warp-speed equations to validate whether they’re practical.

“When somebody publishes a warp metric for the first time, people say, ‘Okay, is your metric physical?’” Martire says. The answer to that question—whether the metric has practical potential or is strictly theoretical—is hard to establish given the challenges of testing these hypotheses. That determination could take six to eight months. “Now we can tell you within seconds, and it shows you visually how off you are or how close you are,” he says.

While useful, the app will speed up the preliminary math only for future researchers. Galaxy-sized challenges remain before we ever experience turbocharged interstellar travel. Alcubierre worries in particular about what may happen near the walls of the warp bubble. The distortion of space is so violent there, he notes, that it would destroy anything that gets close. “If you collide with something on your path, it would almost certainly be catastrophic,” he says.

Natário mulls even more practical issues, like steering and stopping. “It’s a bubble of space, that you’re pushing through space,” he says. “So, you’d have to tell space ... to curve in front of your spaceship.” But therein lies the problem: You can’t signal to the space in front of you to behave the way you want it to.

His opinion? Superluminal travel is impossible. “You need these huge deformations that we have no idea how to accomplish,” Natário says. “So yes, there has been a lot of effort toward this and studying these weird solutions, but this is all still completely theoretical, abstract, and very, very, very, very far from getting anywhere near a practical warp drive.” That’s “very” to the power of four, mind you—each crushing blow pushing us exponentially, excruciatingly further and further away from our yearned-for superluminal lives.

Ultimately, the pursuit of viable high-speed interstellar transportation also points to a more pressing terrestrial challenge: how the scientific community tackles ultra-long-term challenges in the first place. Most of the research so far has come from self-starters without direct funding, or by serendipitous discoveries made while exploring often unrelated research, such as Dr. White’s work on Casimir cavities.

Many scientists argue that we’re in a multi-decade period of stagnation in physics research, and warp drive—despite its epic time horizons before initial research leads to galaxy-spanning adventures—is somewhat emblematic of that stagnation. Sabine Hossenfelder, a research fellow at the Frankfurt Institute for Advanced Studies and creator of the YouTube channel Science Without the Gobbledygook , noted in a 2020 blog post that physics research has drifted away from frequent, persistent physical experimentation to exorbitant infusions of cash into relatively few devices. She writes that with fewer experiments, serendipitous discoveries become increasingly unlikely. Without those discoveries, the technological progress needed to keep experiments economically viable never materializes.

When asked whether this applied equally to warp drive, Hossenfelder sees a faint but plausible connection. “Warp drives are an idea that is not going to lead to applications in the next 1,000 years or so,” she says. “So they don’t play a big role in that one way to another. But when it comes to the funding, you see some overlap in the problems.”

So, despite all the advances, the horizon for a warp drive remains achingly remote. That hasn’t fazed the scientists involved, though. A few years ago, while teaching in France, White visited the Strasbourg Cathedral with his wife. While admiring its 466-foot-tall spire, he was struck by the fact that construction began in 1015 but didn’t wrap up until 1439—a span of 424 years. Those who built the basement had no chance of ever seeing the finished product, but they knew they had to do their part to aid future generations. “I don’t have a crystal ball,” White says. “I don’t know what the future holds. But I know what I need to be doing right now.”

Eric Adams is a writer and photographer who focuses on technology, transportation, science, travel, and other subjects for a wide range of outlets, including Wired, The Drive, Gear Patrol, Men's Health, Popular Science, Forbes, and others.

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

US Army Accepts Delivery of First M10 Assault Gun

Underwater UFO is a Threat, Says Ex-Navy Officer

DIY Car Key Programming: Why Pay the Dealer?

Use Induction Heat to Break Free Rusted Bolts

How to Replace Your Car’s Brakes

The Air Force is Resurrecting a B-1 Bomber

Who Killed Harry Houdini?

A New Hypersonic Missile Will Give the F-35 Fangs

The Navy’s New Drone Could Turn into a Ship-Killer

The CIA’s Secret Plan to Turn Psychics Into Spies

Is This the Real Iceberg That Sank the Titanic?

Suggested Searches

• Climate Change
• Expedition 64
• Mars perseverance
• SpaceX Crew-2
• International Space Station
• View All Topics A-Z

Humans in Space

Earth & climate, the solar system, the universe, aeronautics, learning resources, news & events.

NASA-Led Study Provides New Global Accounting of Earth’s Rivers

NASA’s Hubble Pauses Science Due to Gyro Issue

NASA’s Optical Comms Demo Transmits Data Over 140 Million Miles

• Search All NASA Missions
• A to Z List of Missions
• Upcoming Launches and Landings
• Spaceships and Rockets
• Communicating with Missions
• James Webb Space Telescope
• Hubble Space Telescope
• Why Go to Space
• Astronauts Home
• Commercial Space
• Destinations
• Living in Space
• Explore Earth Science
• Earth, Our Planet
• Earth Science in Action
• Earth Multimedia
• Earth Science Researchers
• Pluto & Dwarf Planets
• Asteroids, Comets & Meteors
• The Kuiper Belt
• The Oort Cloud
• Skywatching
• The Search for Life in the Universe
• Black Holes
• The Big Bang
• Dark Energy & Dark Matter
• Earth Science
• Planetary Science
• Astrophysics & Space Science
• The Sun & Heliophysics
• Biological & Physical Sciences
• Lunar Science
• Citizen Science
• Astromaterials
• Aeronautics Research
• Human Space Travel Research
• Science in the Air
• NASA Aircraft
• Flight Innovation
• Supersonic Flight
• Air Traffic Solutions
• Green Aviation Tech
• Drones & You
• Technology Transfer & Spinoffs
• Space Travel Technology
• Technology Living in Space
• Manufacturing and Materials
• Science Instruments
• For Kids and Students
• For Educators
• For Colleges and Universities
• For Professionals
• Science for Everyone
• Requests for Exhibits, Artifacts, or Speakers
• STEM Engagement at NASA
• NASA's Impacts
• Centers and Facilities
• Directorates
• Organizations
• People of NASA
• Internships
• Our History
• Doing Business with NASA
• Get Involved
• Aeronáutica
• Ciencias Terrestres
• Sistema Solar
• All NASA News
• Video Series on NASA+
• Newsletters
• Social Media
• Media Resources
• Upcoming Launches & Landings
• Virtual Events
• Sounds and Ringtones
• Interactives
• STEM Multimedia

Correction and Clarification of C.26 Rapid Mission Design Studies for Mars Sample Return

NASA’s Commercial Partners Deliver Cargo, Crew for Station Science

NASA Shares Lessons of Human Systems Integration with Industry

Work Underway on Large Cargo Landers for NASA’s Artemis Moon Missions

NASA’s ORCA, AirHARP Projects Paved Way for PACE to Reach Space

Amendment 11: Physical Oceanography not solicited in ROSES-2024

Why is Methane Seeping on Mars? NASA Scientists Have New Ideas

Mars Science Laboratory: Curiosity Rover

Hubble Spots a Magnificent Barred Galaxy

NASA’s Chandra Releases Doubleheader of Blockbuster Hits

Explore the Universe with the First E-Book from NASA’s Fermi

NASA Grant Brings Students at Underserved Institutions to the Stars

NASA Photographer Honored for Thrilling Inverted In-Flight Image

NASA’s Ingenuity Mars Helicopter Team Says Goodbye … for Now

NASA Langley Team to Study Weather During Eclipse Using Uncrewed Vehicles

NASA Data Helps Beavers Build Back Streams

NASA’s Near Space Network Enables PACE Climate Mission to ‘Phone Home’

Washington State High Schooler Wins 2024 NASA Student Art Contest

NASA STEM Artemis Moon Trees

Kiyun Kim: From Intern to Accessibility Advocate

Diez maneras en que los estudiantes pueden prepararse para ser astronautas

Astronauta de la NASA Marcos Berríos

Resultados científicos revolucionarios en la estación espacial de 2023

NASA’s Guide to Near-light-speed Travel

Grade Levels

Grades 5-8, Grades 9-12

Physical Science, Waves, Forces and Motion, Light

Read About It, Videos

Watch this video to learn about near-light-speed safety considerations, travel times and distances between popular destinations around the universe. You can also download shorter clips from the video and printable postcards to send to your friends.

NASA's Guide to Near-light-speed Travel

• Released Friday, August 14, 2020
• Produced by:
• Chris Smith
• Written by:
• Visualizations by:
• Krystofer Kim
• Scientific consulting by:
• Ryan DeRosa
• and Scott Noble

So, you've just put the finishing touches on upgrades to your spaceship, and now it can fly at almost the speed of light. We're not quite sure how you pulled it off, but congratulations! Before you fly off on your next vacation, however, watch this handy video to learn more about near-light-speed safety considerations, travel times, and distances between some popular destinations around the universe. You can also download shorter clips from the video and printable postcards to send to your friends.

Near-light-speed Travel GuideThis handy video will help acquaint you with the quirks of near-light-speed travel, expected travel times, and the distances to some popular (at least, we think so) destinations!Credit: NASA's Goddard Space Flight CenterMusic: "The Tiptoe Strut" from Universal Production MusicComplete transcript available.

• traveler_near_light_speed_HQ_1080.mp4 (1920x1080) [385.7 MB]
• traveler_near_light_speed_HQ_1080.webm (1920x1080) [20.4 MB]
• traveler_near_light_speed_HQ_4K.mp4 (3840x2160) [1.4 GB]
• traveler_near_light_speed_LQ_4K.mp4 (3840x2160) [190.8 MB]
• traveler_near_light_speed_prores.mov (3840x2160) [8.4 GB]
• traveler_near_light_speed.en_US.srt [4.5 KB]
• traveler_near_light_speed.en_US.vtt [4.3 KB]
• traveler_near_light_speed_still.jpg (3840x2160) [4.6 MB]
• traveler_near_light_speed_still_print.jpg (1024x576) [378.3 KB]
• traveler_near_light_speed_still_searchweb.png (320x180) [83.4 KB]
• traveler_near_light_speed_still_web.png (320x180) [83.4 KB]
• traveler_near_light_speed_still_thm.png (80x40) [6.3 KB]

Complete transcript available.

Near Light Speed 101: Effects of Near-light-speed TravelTravel at near the speed of light offers a few quirks you should be aware of, from time and space weirdness to protecting yourself from dangerous cosmic particles. This video covers some of the important ones!Credit: NASA's Goddard Space Flight CenterMusic: "Dinner With the Vicar" from Universal Production MusicComplete transcript available.

• traveler_near_light_speed_segment_effects_HQ_1080.mp4 (1920x1080) [117.3 MB]
• traveler_near_light_speed_segment_effects_HQ_1080.webm (1920x1080) [7.2 MB]
• traveler_near_light_speed_segment_effects_HQ_4K.mp4 (3840x2160) [500.7 MB]
• traveler_near_light_speed_segment_effects_LQ_4K.mp4 (3840x2160) [66.1 MB]
• traveler_near_light_speed_segment_effects_prores.mov (3840x2160) [2.8 GB]
• traveler_near_light_speed_segment_effects.en_US.srt [1.6 KB]
• traveler_near_light_speed_segment_effects.en_US.vtt [1.6 KB]
• traveler_near_light_speed_segment_effects_still.jpg (3840x2160) [3.0 MB]
• traveler_near_light_speed_segment_effects_still_print.jpg (1024x576) [285.5 KB]
• traveler_near_light_speed_segment_effects_still_searchweb.png (320x180) [68.7 KB]
• traveler_near_light_speed_segment_effects_still_web.png (320x180) [68.7 KB]
• traveler_near_light_speed_segment_effects_still_thm.png (80x40) [6.7 KB]

Near Light Speed 101: Near-light-speed Travel TimesEven if you've figured out how to travel at almost the speed of light, the universe is still a huge place! Watch this video to learn more about how long it takes to cruise around the cosmos.Credit: NASA's Goddard Space Flight CenterMusic: "Dinner With the Vicar" from Universal Production MusicComplete transcript available.

• traveler_near_light_speed_segment_travel_times_HQ_1080.mp4 (1920x1080) [126.3 MB]
• traveler_near_light_speed_segment_travel_times_HQ_1080.webm (1920x1080) [8.0 MB]
• traveler_near_light_speed_segment_travel_times_HQ_4K.mp4 (3840x2160) [554.3 MB]
• traveler_near_light_speed_segment_travel_times_LQ_4K.mp4 (3840x2160) [74.8 MB]
• traveler_near_light_speed_segment_travel_times_prores.mov (3840x2160) [3.1 GB]
• traveler_near_light_speed_segment_travel_times.en_US.srt [1.7 KB]
• traveler_near_light_speed_segment_travel_times.en_US.vtt [1.6 KB]
• traveler_near_light_speed_segment_travel_times_still.jpg (3840x2160) [2.2 MB]
• traveler_near_light_speed_segment_travel_times_still_print.jpg (1024x576) [227.3 KB]
• traveler_near_light_speed_segment_travel_times_still_searchweb.png (320x180) [60.6 KB]
• traveler_near_light_speed_segment_travel_times_still_web.png (320x180) [60.6 KB]
• traveler_near_light_speed_segment_travel_times_still_thm.png (80x40) [6.0 KB]
• near_light_speed_postcard.png (3148x2225) [1.6 MB]
• near_light_speed_postcard_print.jpg (1024x723) [175.0 KB]
• near_light_speed_postcard_searchweb.png (180x320) [67.8 KB]
• near_light_speed_postcard_web.png (320x226) [79.0 KB]
• near_light_speed_postcard_thm.png (80x40) [6.5 KB]

*compared to friends that stayed behind.

• solar_system_postcard.png (3148x2225) [1.7 MB]
• solar_system_postcard_print.jpg (1024x723) [150.0 KB]
• solar_system_postcard_searchweb.png (320x180) [67.7 KB]
• solar_system_postcard_web.png (320x226) [74.9 KB]
• solar_system_postcard_thm.png (80x40) [6.7 KB]

Visit sunny Glerbax-29, home of eight unique, beautiful planets! The locals call it the solar system.

• Andromeda_postcard.png (3148x2225) [1.5 MB]
• Andromeda_postcard_print.jpg (1024x723) [138.2 KB]
• Andromeda_postcard_searchweb.png (320x180) [62.9 KB]
• Andromeda_postcard_web.png (320x226) [72.9 KB]
• Andromeda_postcard_thm.png (80x40) [6.1 KB]

A vacation to Andromeda, our nearest spiral neighbor galaxy, is a long, long, long, long, long trip, but it's worth it! And this postcard will prove it to your friends.

• Astrophysics

Please give credit for this item to: NASA's Goddard Space Flight Center

• Chris Smith  (USRA)
• Krystofer Kim  (USRA)
• Ryan DeRosa  (NASA/GSFC)
• Scott Noble  (NASA/GSFC)

Release date

This page was originally published on Friday, August 14, 2020. This page was last updated on Wednesday, May 3, 2023 at 1:44 PM EDT.

• Narrated Movies

Snap It! An Eclipse Photo Adventure (Trailer)

Nasa’s guide to visiting a gamma-ray burst, nasa's field guide to black holes, nasa's guide to black hole safety, you may also like..., no results., an error occurred. please reload this page and try again..

New technology could enable humans to travel at 7 million MPH

At 1 percent the speed of light, it would take a little over a second to get from Los Angeles to New York.

Light is fast . In fact, it is the fastest thing that exists, and a law of the universe is that nothing can move faster than light. Light travels at 186,000 miles per second (300,000 kilometers per second) and can go from the Earth to the Moon in just over a second. Light can streak from Los Angeles to New York in less than the blink of an eye.

While 1 percent of anything doesn’t sound like much, with light, that’s still really fast — close to 7 million miles per hour! At 1 percent the speed of light, it would take a little over a second to get from Los Angeles to New York. This is more than 10,000 times faster than a commercial jet.

The Parker Solar Probe, seen here in an artist’s rendition, is the fastest object ever made by humans and used the gravity of the Sun to get going 0.05% the speed of light.

What is the fastest man-made object

Bullets can go 2,600 miles per hour (mph), more than three times the speed of sound. The fastest aircraft is NASA’s X3 jet plane , with a top speed of 7,000 mph. That sounds impressive, but it’s still only 0.001 percent the speed of light.

The fastest human-made objects are spacecraft. They use rockets to break free of the Earth’s gravity, which takes a speed of 25,000 mph. The spacecraft that is traveling the fastest is NASA’s Parker Solar Probe . After it launched from Earth in 2018, it skimmed the Sun’s scorching atmosphere and used the Sun’s gravity to reach 330,000 mph. That’s blindingly fast — yet only 0.05% of the speed of light.

Why even 1 percent of light speed is hard

What’s holding humanity back from reaching 1 percent of the speed of light? In a word, energy. Any object that’s moving has energy due to its motion. Physicists call this kinetic energy. To go faster, you need to increase kinetic energy. The problem is that it takes a lot of kinetic energy to increase speed. To make something go twice as fast takes four times the energy. Making something go three times as fast requires nine times the energy, and so on.

For example, to get a teenager who weighs 110 pounds to 1 percent of the speed of light would cost 200 trillion Joules (a measurement of energy). That’s roughly the same amount of energy that 2 million people in the U.S. use in a day.

Light sails like these seen in an illustration could get us to the stars.

How fast can we go?

It’s possible to get something to 1 percent the speed of light, but it would just take an enormous amount of energy. Could humans make something go even faster?

Yes! But engineers need to figure out new ways to make things move in space. All rockets, even the sleek new rockets used by SpaceX and Blue Origins, burn rocket fuel that isn’t very different from gasoline in a car. The problem is that burning fuel is very inefficient.

Other methods for pushing a spacecraft involve using electric or magnetic forces . Nuclear fusion , the process that powers the Sun, is also much more efficient than chemical fuel.

Scientists are researching many other ways to go fast — even warp drives , the faster-than-light travel popularized by Star Trek .

One promising way to get something moving very fast is to use a solar sail. These are large, thin sheets of plastic attached to a spacecraft and designed so that sunlight can push on them, like the wind in a normal sail. A few spacecraft have used solar sails to show that they work, and scientists think that a solar sail could propel spacecraft to 10 percent of the speed of light .

One day, when humanity is not limited to a tiny fraction of the speed of light, we might travel to the stars .

This article was originally published on The Conversation by Chris Impey. Read the original article here.

This article was originally published on November 22, 2021

• Space Science

share this!

March 28, 2024

This article has been reviewed according to Science X's editorial process and policies . Editors have highlighted the following attributes while ensuring the content's credibility:

fact-checked

peer-reviewed publication

trusted source

From Earth to Mars: Transporting spin information at the speed of light

by Tom Dinki and Christophe Cartier dit Moulin, University at Buffalo

Scientists have used electrical pulses to manipulate magnetic information into a polarized light signal, a discovery that could revolutionize long-distance optical telecommunications, including between Earth and Mars.

The breakthrough, described in a study published in Nature , involves the field of spintronics, which aims to manipulate the spin of electrons in order to store and process information.

The researchers applied an electrical pulse to transfer this spin information from electrons to photons, the particles that make up light, allowing the information to be carried great distances at great speed. Their method meets three crucial criteria—operation at room temperature, no need of magnetic field and the ability for electrical control—and opens the door to a range of applications, including ultrafast communication and quantum technologies.

"For decades we were dreaming of and predicting room-temperature spintronic devices beyond magnetoresistance and just storing information. With this team's discovery, our dreams become reality," says the study's co-author, Igor Žutić, SUNY Distinguished Professor of physics at the University at Buffalo.

The study was led by the Jean Lamour Institute, a joint unit of France's National Center for Scientific Research (CNRS) and the University of Lorraine. Other contributors represent universities and institutes in France, Germany, Japan, China and the United States.

Spintronic devices could replace conventional electronics

In spintronics, which has been used successfully in magnetic computer hard drives, information is represented by electron spin and, by its proxy, the direction of magnetization.

Ferromagnets, such as iron or cobalt, have an unequal number of electrons whose spins are oriented either along or against the magnetization axis. Electrons with spin along the magnetization travel smoothly across a ferromagnet, while those with opposite spin orientation are bounced around. This represents binary information, 0 and 1.

The resulting change of the resistance is the key principle for spintronic devices, whose magnetic state, which can be considered as stored information, is maintained indefinitely. Just as a fridge magnet does not need power to remain stuck to the door, spintronic devices would require much less power than conventional electronics.

However, akin to taking a fish out of water, spin information is quickly lost and cannot travel far when electrons are taken out of the ferromagnet. This major limitation can be overcome by utilizing light through its circular polarization , also known as helicity, as another spin carrier.

Just as humans centuries ago used carrier pigeons to transport written communication farther and faster than could be done on foot, the trick would be to transfer electron spin to photos, the quantum of light.

Spin-LEDs meet three criteria

The presence of spin-orbit coupling, which is also responsible for the spin information loss outside of the ferromagnet, makes such transfer possible. The crucial missing link is then to electrically modulate the magnetization and thereby change the helicity of the emitted light.

"The concept of spin-LEDs was initially proposed at the end of the last century. However, for the transition into a practical application, it must meet three crucial criteria: operation at room temperature, no need of magnetic field, and the ability for electrical control," says the study's corresponding author, Yuan Lu, senior CNRS researcher at the Jean Lamour Institute.

"After more than 15 years of dedicated work in this field, our collaborative team has successfully conquered all obstacles."

The researchers successfully switched the magnetization of a spin injector by an electrical pulse using the spin-orbit torque. The electron's spin is rapidly converted into information contained in the helicity of the emitted photons, enabling a seamless integration of magnetization dynamics with photonic technologies.

This electrically controlled spin-photon conversion is now achieved in the electroluminescence of light-emitting diodes. In the future, through the implementation in semiconductor laser diodes, so-called spin-lasers, this highly-efficient information encoding could pave the way for rapid communication over interplanetary distances since polarization of light can be conserved in space propagation, potentially making it the fastest mode of communication between Earth and Mars.

It will also greatly benefit the development of various advanced technologies on Earth, such as optical quantum communication and computation, neuromorphic computing for artificial intelligence , ultrafast and highly-efficient optical transmitters for data centers or Light-Fidelity (LiFi) applications.

"The realization of spin-orbit-torque spin injectors is a decisive step that will greatly advance the development of ultrafast and energy-efficient spin-lasers for the next generation of optical communication and quantum technologies," says co-author Nils Gerhardt, professor at the Chair of Photonics and Terahertz Technology at the Ruhr University in Bochum.

Journal information: Nature

Provided by University at Buffalo

Explore further

Feedback to editors

Optical barcodes expand range of high-resolution sensor

3 hours ago

Ridesourcing platforms thrive on socio-economic inequality, say researchers

4 hours ago

Did Vesuvius bury the home of the first Roman emperor?

Florida dolphin found with highly pathogenic avian flu: Report

A new way to study and help prevent landslides

New algorithm cuts through 'noisy' data to better predict tipping points

5 hours ago

Researchers reconstruct landscapes that greeted the first humans in Australia around 65,000 years ago

High-precision blood glucose level prediction achieved by few-molecule reservoir computing

6 hours ago

Enhancing memory technology: Multiferroic nanodots for low-power magnetic storage

Researchers advance detection of gravitational waves to study collisions of neutron stars and black holes

Relevant physicsforums posts, how can i calculate spin hall conductivity for a 4*4 hamiltonian, hall effect in p-type semiconductors: electron-centric heuristic.

19 hours ago

Insulator band gap and applied voltage?

Apr 24, 2024

Cavity locking using Lockin PID technique

Question about cgs vs si units in the context of the debye length.

Apr 22, 2024

Looking for study group to hack on basic theory in condensed matter

Apr 20, 2024

More from Atomic and Condensed Matter

Related Stories

Highly efficient means to reverse magnetization with spin currents

Apr 25, 2022

When light and electrons spin together

Jul 12, 2022

Researchers learn to control electron spin at room temperature to make devices more efficient and faster

Jul 14, 2022

Physicists uncover 'parallel circuits' of spin currents in antiferromagnets

Jun 7, 2023

Toward 2D memory technology by magnetic graphene

May 6, 2021

Sub-picosecond magnetization reversal in rare-earth-free spin valves

Mar 10, 2023

Recommended for you

Unveiling a new quantum frontier: Frequency-domain entanglement

Research demonstrates a new mechanism of order formation in quantum systems

7 hours ago

Scientists simulate magnetization reversal of Nd-Fe-B magnets using large-scale finite element models

8 hours ago

Demonstration of heralded three-photon entanglement on a photonic chip

Apr 25, 2024

Airborne single-photon lidar system achieves high-resolution 3D imaging

Let us know if there is a problem with our content.

Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form . For general feedback, use the public comments section below (please adhere to guidelines ).

Please select the most appropriate category to facilitate processing of your request

Thank you for taking time to provide your feedback to the editors.

Your feedback is important to us. However, we do not guarantee individual replies due to the high volume of messages.

E-mail the story

Your email address is used only to let the recipient know who sent the email. Neither your address nor the recipient's address will be used for any other purpose. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form.

Newsletter sign up

Get weekly and/or daily updates delivered to your inbox. You can unsubscribe at any time and we'll never share your details to third parties.

More information Privacy policy

Donate and enjoy an ad-free experience

We keep our content available to everyone. Consider supporting Science X's mission by getting a premium account.

E-mail newsletter

• International edition
• Australia edition
• Europe edition

Voyager 1 transmitting data again after Nasa remotely fixes 46-year-old probe

Engineers spent months working to repair link with Earth’s most distant spacecraft, says space agency

Earth’s most distant spacecraft, Voyager 1, has started communicating properly again with Nasa after engineers worked for months to remotely fix the 46-year-old probe.

Nasa’s Jet Propulsion Laboratory (JPL), which makes and operates the agency’s robotic spacecraft, said in December that the probe – more than 15bn miles (24bn kilometres) away – was sending gibberish code back to Earth.

In an update released on Monday , JPL announced the mission team had managed “after some inventive sleuthing” to receive usable data about the health and status of Voyager 1’s engineering systems. “The next step is to enable the spacecraft to begin returning science data again,” JPL said. Despite the fault, Voyager 1 had operated normally throughout, it added.

Launched in 1977, Voyager 1 was designed with the primary goal of conducting close-up studies of Jupiter and Saturn in a five-year mission. However, its journey continued and the spacecraft is now approaching a half-century in operation.

Voyager 1 crossed into interstellar space in August 2012, making it the first human-made object to venture out of the solar system. It is currently travelling at 37,800mph (60,821km/h).

Hi, it's me. - V1 https://t.co/jgGFBfxIOe — NASA Voyager (@NASAVoyager) April 22, 2024

The recent problem was related to one of the spacecraft’s three onboard computers, which are responsible for packaging the science and engineering data before it is sent to Earth. Unable to repair a broken chip, the JPL team decided to move the corrupted code elsewhere, a tricky job considering the old technology.

The computers on Voyager 1 and its sister probe, Voyager 2, have less than 70 kilobytes of memory in total – the equivalent of a low-resolution computer image. They use old-fashioned digital tape to record data.

The fix was transmitted from Earth on 18 April but it took two days to assess if it had been successful as a radio signal takes about 22 and a half hours to reach Voyager 1 and another 22 and a half hours for a response to come back to Earth. “When the mission flight team heard back from the spacecraft on 20 April, they saw that the modification worked,” JPL said.

Alongside its announcement, JPL posted a photo of members of the Voyager flight team cheering and clapping in a conference room after receiving usable data again, with laptops, notebooks and doughnuts on the table in front of them.

The Retired Canadian astronaut Chris Hadfield, who flew two space shuttle missions and acted as commander of the International Space Station, compared the JPL mission to long-distance maintenance on a vintage car.

“Imagine a computer chip fails in your 1977 vehicle. Now imagine it’s in interstellar space, 15bn miles away,” Hadfield wrote on X . “Nasa’s Voyager probe just got fixed by this team of brilliant software mechanics.

Voyager 1 and 2 have made numerous scientific discoveries , including taking detailed recordings of Saturn and revealing that Jupiter also has rings, as well as active volcanism on one of its moons, Io. The probes later discovered 23 new moons around the outer planets.

As their trajectory takes them so far from the sun, the Voyager probes are unable to use solar panels, instead converting the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft’s systems.

Nasa hopes to continue to collect data from the two Voyager spacecraft for several more years but engineers expect the probes will be too far out of range to communicate in about a decade, depending on how much power they can generate. Voyager 2 is slightly behind its twin and is moving slightly slower.

In roughly 40,000 years, the probes will pass relatively close, in astronomical terms, to two stars. Voyager 1 will come within 1.7 light years of a star in the constellation Ursa Minor, while Voyager 2 will come within a similar distance of a star called Ross 248 in the constellation of Andromeda.

More on this story

Cosmic cleaners: the scientists scouring English cathedral roofs for space dust

Russia acknowledges continuing air leak from its segment of space station

Uncontrolled European satellite falls to Earth after 30 years in orbit

Cosmonaut Oleg Kononenko sets world record for most time spent in space

‘Old smokers’: astronomers discover giant ancient stars in Milky Way

Nasa postpones plans to send humans to moon

What happened to the Peregrine lander and what does it mean for moon missions?

Peregrine 1 has ‘no chance’ of landing on moon due to fuel leak

Most viewed.

• Search Please fill out this field.
• Manage Your Subscription
• Give a Gift Subscription
• Sweepstakes
• Space Travel + Astronomy

Here's What Actually Happens When You Travel at the Speed of Light, According to NASA

NASA created a fun video to answer all of our burning questions about near-light-speed travel.

Ever wish you could travel at the speed of light to your favorite destinations ? Once you see the reality of that speed, you may rethink everything.

"There are some important things you should probably know about approaching the speed of light," NASA's video, Guide to Near-light-speed Travel , explains. "First, a lot of weird things can happen, like time and space getting all bent out of shape."

According to the video, if you're traveling at nearly the speed of light, the clock inside your rocket would show it takes less time to travel to your destination than it would on Earth. But, since the clocks at home would be moving at a standard rate you'd return home to everyone else being quite a bit older.

"Also, because you're going so fast, what would otherwise be just a few hydrogen atoms that you'd run into quickly becomes a lot of dangerous particles. So you should probably have shields that keep them from frying your ship and also you."

Finally, the video tackles the fact that even if you were moving at the speed of light, the "universe is also a very big place, so you might be in for some surprises." For example, your rocket's clock will say it takes about nine months to get from Earth to the edge of the solar system. An Earth clock would say it took about a year and a half. Fortunately, NASA astronauts have a slew of tips for avoiding jet lag along the way.

"If you want to get to farther out vacation spots," the video explains, "you'll probably need more than a few extra snacks. A trip to the Andromeda Galaxy, our nearest large neighbor galaxy, can take over one million years. And a trip to the farthest known galaxy where it currently sits might take over 15 billion years, which is more vacation time than I think I'll ever have."

The video doesn't explain how your rocket will travel at the speed of light. Our technology just isn't there yet, but maybe the aliens will share that tech with us soon. Until then, you can track the first crew launch of Artemis II , a rocket that will fly around the moon in 2024 before making its first lunar landing in 2025.

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

How scientists are using quantum squeezing to push the limits of their sensors

Fuzziness may rule the quantum realm, but it can be manipulated to our advantage.

• Sophia Chen 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.

What is the speed of light?

The speed of light is the speed limit of the universe. Or is it?

What is a light-year?

• Speed of light FAQs
• Special relativity
• Faster than light
• Slowing down light
• Faster-than-light travel

Bibliography

The speed of light traveling through a vacuum is exactly 299,792,458 meters (983,571,056 feet) per second. That's about 186,282 miles per second — a universal constant known in equations as "c," or light speed. 

According to physicist Albert Einstein 's theory of special relativity , on which much of modern physics is based, nothing in the universe can travel faster than light. The theory states that as matter approaches the speed of light, the matter's mass becomes infinite. That means the speed of light functions as a speed limit on the whole universe . The speed of light is so immutable that, according to the U.S. National Institute of Standards and Technology , it is used to define international standard measurements like the meter (and by extension, the mile, the foot and the inch). Through some crafty equations, it also helps define the kilogram and the temperature unit Kelvin .

But despite the speed of light's reputation as a universal constant, scientists and science fiction writers alike spend time contemplating faster-than-light travel. So far no one's been able to demonstrate a real warp drive, but that hasn't slowed our collective hurtle toward new stories, new inventions and new realms of physics.

Related: Special relativity holds up to a high-energy test

A l ight-year is the distance that light can travel in one year — about 6 trillion miles (10 trillion kilometers). It's one way that astronomers and physicists measure immense distances across our universe.

Light travels from the moon to our eyes in about 1 second, which means the moon is about 1 light-second away. Sunlight takes about 8 minutes to reach our eyes, so the sun is about 8 light minutes away. Light from Alpha Centauri , which is the nearest star system to our own, requires roughly 4.3 years to get here, so Alpha Centauri is 4.3 light-years away.

"To obtain an idea of the size of a light-year, take the circumference of the Earth (24,900 miles), lay it out in a straight line, multiply the length of the line by 7.5 (the corresponding distance is one light-second), then place 31.6 million similar lines end to end," NASA's Glenn Research Center says on its website . "The resulting distance is almost 6 trillion (6,000,000,000,000) miles!"

Stars and other objects beyond our solar system lie anywhere from a few light-years to a few billion light-years away. And everything astronomers "see" in the distant universe is literally history. When astronomers study objects that are far away, they are seeing light that shows the objects as they existed at the time that light left them. 

This principle allows astronomers to see the universe as it looked after the Big Bang , which took place about 13.8 billion years ago. Objects that are 10 billion light-years away from us appear to astronomers as they looked 10 billion years ago — relatively soon after the beginning of the universe — rather than how they appear today.

Related: Why the universe is all history

Speed of light FAQs answered by an expert

We asked Rob Zellem, exoplanet-hunter and staff scientist at NASA's Jet Propulsion Lab, a few frequently asked questions about the speed of light. 

Dr. Rob Zellem is a staff scientist at NASA's Jet Propulsion Laboratory, a federally funded research and development center operated by the California Institute of Technology. Rob is the project lead for Exoplanet Watch, a citizen science project to observe exoplanets, planets outside of our own solar system, with small telescopes. He is also the Science Calibration lead for the Nancy Grace Roman Space Telescope's Coronagraph Instrument, which will directly image exoplanets. 

What is faster than the speed of light?

Nothing! Light is a "universal speed limit" and, according to Einstein's theory of relativity, is the fastest speed in the universe: 300,000 kilometers per second (186,000 miles per second). 

Is the speed of light constant?

The speed of light is a universal constant in a vacuum, like the vacuum of space. However, light *can* slow down slightly when it passes through an absorbing medium, like water (225,000 kilometers per second = 140,000 miles per second) or glass (200,000 kilometers per second = 124,000 miles per second). 

Who discovered the speed of light?

One of the first measurements of the speed of light was by Rømer in 1676 by observing the moons of Jupiter . The speed of light was first measured to high precision in 1879 by the Michelson-Morley Experiment. 

How do we know the speed of light?

Rømer was able to measure the speed of light by observing eclipses of Jupiter's moon Io. When Jupiter was closer to Earth, Rømer noted that eclipses of Io occurred slightly earlier than when Jupiter was farther away. Rømer attributed this effect due the time it takes for light to travel over the longer distance when Jupiter was farther from the Earth. 

How did we learn the speed of light?

As early as the 5th century BC, Greek philosophers like Empedocles and Aristotle disagreed on the nature of light speed. Empedocles proposed that light, whatever it was made of, must travel and therefore, must have a rate of travel. Aristotle wrote a rebuttal of Empedocles' view in his own treatise, On Sense and the Sensible , arguing that light, unlike sound and smell, must be instantaneous. Aristotle was wrong, of course, but it would take hundreds of years for anyone to prove it. 

In the mid 1600s, the Italian astronomer Galileo Galilei stood two people on hills less than a mile apart. Each person held a shielded lantern. One uncovered his lantern; when the other person saw the flash, he uncovered his too. But Galileo's experimental distance wasn't far enough for his participants to record the speed of light. He could only conclude that light traveled at least 10 times faster than sound.

In the 1670s, Danish astronomer Ole Rømer tried to create a reliable timetable for sailors at sea, and according to NASA , accidentally came up with a new best estimate for the speed of light. To create an astronomical clock, he recorded the precise timing of the eclipses of Jupiter's moon , Io, from Earth . Over time, Rømer observed that Io's eclipses often differed from his calculations. He noticed that the eclipses appeared to lag the most when Jupiter and Earth were moving away from one another, showed up ahead of time when the planets were approaching and occurred on schedule when the planets were at their closest or farthest points. This observation demonstrated what we today know as the Doppler effect, the change in frequency of light or sound emitted by a moving object that in the astronomical world manifests as the so-called redshift , the shift towards "redder", longer wavelengths in objects speeding away from us. In a leap of intuition, Rømer determined that light was taking measurable time to travel from Io to Earth. 

Rømer used his observations to estimate the speed of light. Since the size of the solar system and Earth's orbit wasn't yet accurately known, argued a 1998 paper in the American Journal of Physics , he was a bit off. But at last, scientists had a number to work with. Rømer's calculation put the speed of light at about 124,000 miles per second (200,000 km/s).

In 1728, English physicist James Bradley based a new set of calculations on the change in the apparent position of stars caused by Earth's travels around the sun. He estimated the speed of light at 185,000 miles per second (301,000 km/s) — accurate to within about 1% of the real value, according to the American Physical Society .

Two new attempts in the mid-1800s brought the problem back to Earth. French physicist Hippolyte Fizeau set a beam of light on a rapidly rotating toothed wheel, with a mirror set up 5 miles (8 km) away to reflect it back to its source. Varying the speed of the wheel allowed Fizeau to calculate how long it took for the light to travel out of the hole, to the adjacent mirror, and back through the gap. Another French physicist, Leon Foucault, used a rotating mirror rather than a wheel to perform essentially the same experiment. The two independent methods each came within about 1,000 miles per second (1,609 km/s) of the speed of light.

Another scientist who tackled the speed of light mystery was Poland-born Albert A. Michelson, who grew up in California during the state's gold rush period, and honed his interest in physics while attending the U.S. Naval Academy, according to the University of Virginia . In 1879, he attempted to replicate Foucault's method of determining the speed of light, but Michelson increased the distance between mirrors and used extremely high-quality mirrors and lenses. Michelson's result of 186,355 miles per second (299,910 km/s) was accepted as the most accurate measurement of the speed of light for 40 years, until Michelson re-measured it himself. In his second round of experiments, Michelson flashed lights between two mountain tops with carefully measured distances to get a more precise estimate. And in his third attempt just before his death in 1931, according to the Smithsonian's Air and Space magazine, he built a mile-long depressurized tube of corrugated steel pipe. The pipe simulated a near-vacuum that would remove any effect of air on light speed for an even finer measurement, which in the end was just slightly lower than the accepted value of the speed of light today. 

Michelson also studied the nature of light itself, wrote astrophysicist Ethan Siegal in the Forbes science blog, Starts With a Bang . The best minds in physics at the time of Michelson's experiments were divided: Was light a wave or a particle? 

Michelson, along with his colleague Edward Morley, worked under the assumption that light moved as a wave, just like sound. And just as sound needs particles to move, Michelson and Morley and other physicists of the time reasoned, light must have some kind of medium to move through. This invisible, undetectable stuff was called the "luminiferous aether" (also known as "ether"). 

Though Michelson and Morley built a sophisticated interferometer (a very basic version of the instrument used today in LIGO facilities), Michelson could not find evidence of any kind of luminiferous aether whatsoever. Light, he determined, can and does travel through a vacuum.

"The experiment — and Michelson's body of work — was so revolutionary that he became the only person in history to have won a Nobel Prize for a very precise non-discovery of anything," Siegal wrote. "The experiment itself may have been a complete failure, but what we learned from it was a greater boon to humanity and our understanding of the universe than any success would have been!"

Special relativity and the speed of light

Einstein's theory of special relativity unified energy, matter and the speed of light in a famous equation: E = mc^2. The equation describes the relationship between mass and energy — small amounts of mass (m) contain, or are made up of, an inherently enormous amount of energy (E). (That's what makes nuclear bombs so powerful: They're converting mass into blasts of energy.) Because energy is equal to mass times the speed of light squared, the speed of light serves as a conversion factor, explaining exactly how much energy must be within matter. And because the speed of light is such a huge number, even small amounts of mass must equate to vast quantities of energy.

In order to accurately describe the universe, Einstein's elegant equation requires the speed of light to be an immutable constant. Einstein asserted that light moved through a vacuum, not any kind of luminiferous aether, and in such a way that it moved at the same speed no matter the speed of the observer. 

Think of it like this: Observers sitting on a train could look at a train moving along a parallel track and think of its relative movement to themselves as zero. But observers moving nearly the speed of light would still perceive light as moving away from them at more than 670 million mph. (That's because moving really, really fast is one of the only confirmed methods of time travel — time actually slows down for those observers, who will age slower and perceive fewer moments than an observer moving slowly.)

In other words, Einstein proposed that the speed of light doesn't vary with the time or place that you measure it, or how fast you yourself are moving. 

Therefore, objects with mass cannot ever reach the speed of light. If an object ever did reach the speed of light, its mass would become infinite. And as a result, the energy required to move the object would also become infinite: an impossibility.

That means if we base our understanding of physics on special relativity (which most modern physicists do), the speed of light is the immutable speed limit of our universe — the fastest that anything can travel. 

What goes faster than the speed of light?

Although the speed of light is often referred to as the universe's speed limit, the universe actually expands even faster. The universe expands at a little more than 42 miles (68 kilometers) per second for each megaparsec of distance from the observer, wrote astrophysicist Paul Sutter in a previous article for Space.com . (A megaparsec is 3.26 million light-years — a really long way.) 

In other words, a galaxy 1 megaparsec away appears to be traveling away from the Milky Way at a speed of 42 miles per second (68 km/s), while a galaxy two megaparsecs away recedes at nearly 86 miles per second (136 km/s), and so on. 

"At some point, at some obscene distance, the speed tips over the scales and exceeds the speed of light, all from the natural, regular expansion of space," Sutter explained. "It seems like it should be illegal, doesn't it?"

Special relativity provides an absolute speed limit within the universe, according to Sutter, but Einstein's 1915 theory regarding general relativity allows different behavior when the physics you're examining are no longer "local."

"A galaxy on the far side of the universe? That's the domain of general relativity, and general relativity says: Who cares! That galaxy can have any speed it wants, as long as it stays way far away, and not up next to your face," Sutter wrote. "Special relativity doesn't care about the speed — superluminal or otherwise — of a distant galaxy. And neither should you."

Does light ever slow down?

Light in a vacuum is generally held to travel at an absolute speed, but light traveling through any material can be slowed down. The amount that a material slows down light is called its refractive index. Light bends when coming into contact with particles, which results in a decrease in speed.

For example, light traveling through Earth's atmosphere moves almost as fast as light in a vacuum, slowing down by just three ten-thousandths of the speed of light. But light passing through a diamond slows to less than half its typical speed, PBS NOVA reported. Even so, it travels through the gem at over 277 million mph (almost 124,000 km/s) — enough to make a difference, but still incredibly fast.

Light can be trapped — and even stopped — inside ultra-cold clouds of atoms, according to a 2001 study published in the journal Nature . More recently, a 2018 study published in the journal Physical Review Letters proposed a new way to stop light in its tracks at "exceptional points," or places where two separate light emissions intersect and merge into one.

Researchers have also tried to slow down light even when it's traveling through a vacuum. A team of Scottish scientists successfully slowed down a single photon, or particle of light, even as it moved through a vacuum, as described in their 2015 study published in the journal Science . In their measurements, the difference between the slowed photon and a "regular" photon was just a few millionths of a meter, but it demonstrated that light in a vacuum can be slower than the official speed of light. 

Can we travel faster than light?

— Spaceship could fly faster than light

— Here's what the speed of light looks like in slow motion

— Why is the speed of light the way it is?

Science fiction loves the idea of "warp speed." Faster-than-light travel makes countless sci-fi franchises possible, condensing the vast expanses of space and letting characters pop back and forth between star systems with ease. 

But while faster-than-light travel isn't guaranteed impossible, we'd need to harness some pretty exotic physics to make it work. Luckily for sci-fi enthusiasts and theoretical physicists alike, there are lots of avenues to explore.

All we have to do is figure out how to not move ourselves — since special relativity would ensure we'd be long destroyed before we reached high enough speed — but instead, move the space around us. Easy, right? 

One proposed idea involves a spaceship that could fold a space-time bubble around itself. Sounds great, both in theory and in fiction.

"If Captain Kirk were constrained to move at the speed of our fastest rockets, it would take him a hundred thousand years just to get to the next star system," said Seth Shostak, an astronomer at the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, California, in a 2010 interview with Space.com's sister site LiveScience . "So science fiction has long postulated a way to beat the speed of light barrier so the story can move a little more quickly."

Without faster-than-light travel, any "Star Trek" (or "Star War," for that matter) would be impossible. If humanity is ever to reach the farthest — and constantly expanding — corners of our universe, it will be up to future physicists to boldly go where no one has gone before.

Additional resources

For more on the speed of light, check out this fun tool from Academo that lets you visualize how fast light can travel from any place on Earth to any other. If you’re more interested in other important numbers, get familiar with the universal constants that define standard systems of measurement around the world with the National Institute of Standards and Technology . And if you’d like more on the history of the speed of light, check out the book " Lightspeed: The Ghostly Aether and the Race to Measure the Speed of Light " (Oxford, 2019) by John C. H. Spence.

Aristotle. “On Sense and the Sensible.” The Internet Classics Archive, 350AD. http://classics.mit.edu/Aristotle/sense.2.2.html .

D’Alto, Nick. “The Pipeline That Measured the Speed of Light.” Smithsonian Magazine, January 2017. https://www.smithsonianmag.com/air-space-magazine/18_fm2017-oo-180961669/ .

Fowler, Michael. “Speed of Light.” Modern Physics. University of Virginia. Accessed January 13, 2022. https://galileo.phys.virginia.edu/classes/252/spedlite.html#Albert%20Abraham%20Michelson .

Giovannini, Daniel, Jacquiline Romero, Václav Potoček, Gergely Ferenczi, Fiona Speirits, Stephen M. Barnett, Daniele Faccio, and Miles J. Padgett. “Spatially Structured Photons That Travel in Free Space Slower than the Speed of Light.” Science, February 20, 2015. https://www.science.org/doi/abs/10.1126/science.aaa3035 .

Goldzak, Tamar, Alexei A. Mailybaev, and Nimrod Moiseyev. “Light Stops at Exceptional Points.” Physical Review Letters 120, no. 1 (January 3, 2018): 013901. https://doi.org/10.1103/PhysRevLett.120.013901 . 

Hazen, Robert. “What Makes Diamond Sparkle?” PBS NOVA, January 31, 2000. https://www.pbs.org/wgbh/nova/article/diamond-science/ . 

“How Long Is a Light-Year?” Glenn Learning Technologies Project, May 13, 2021. https://www.grc.nasa.gov/www/k-12/Numbers/Math/Mathematical_Thinking/how_long_is_a_light_year.htm . 

American Physical Society News. “July 1849: Fizeau Publishes Results of Speed of Light Experiment,” July 2010. http://www.aps.org/publications/apsnews/201007/physicshistory.cfm . 

Liu, Chien, Zachary Dutton, Cyrus H. Behroozi, and Lene Vestergaard Hau. “Observation of Coherent Optical Information Storage in an Atomic Medium Using Halted Light Pulses.” Nature 409, no. 6819 (January 2001): 490–93. https://doi.org/10.1038/35054017 . 

NIST. “Meet the Constants.” October 12, 2018. https://www.nist.gov/si-redefinition/meet-constants . 

Ouellette, Jennifer. “A Brief History of the Speed of Light.” PBS NOVA, February 27, 2015. https://www.pbs.org/wgbh/nova/article/brief-history-speed-light/ . 

Shea, James H. “Ole Ro/Mer, the Speed of Light, the Apparent Period of Io, the Doppler Effect, and the Dynamics of Earth and Jupiter.” American Journal of Physics 66, no. 7 (July 1, 1998): 561–69. https://doi.org/10.1119/1.19020 . 

Siegel, Ethan. “The Failed Experiment That Changed The World.” Forbes, April 21, 2017. https://www.forbes.com/sites/startswithabang/2017/04/21/the-failed-experiment-that-changed-the-world/ . 

Stern, David. “Rømer and the Speed of Light,” October 17, 2016. https://pwg.gsfc.nasa.gov/stargaze/Sun4Adop1.htm . 

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!

Vicky Stein is a science writer based in California. She has a bachelor's degree in ecology and evolutionary biology from Dartmouth College and a graduate certificate in science writing from the University of California, Santa Cruz (2018). Afterwards, she worked as a news assistant for PBS NewsHour, and now works as a freelancer covering anything from asteroids to zebras. Follow her most recent work (and most recent pictures of nudibranchs) on Twitter. 

Satellites watch as 4th global coral bleaching event unfolds (image)

Happy Earth Day 2024! NASA picks 6 new airborne missions to study our changing planet

James Webb Space Telescope discovers some early universe galaxies grew up surprisingly fast

Most Popular

• 2 Alien Day 2024: 'Alien' bursts back into theaters today
• 3 Satellite images overlay 2024 and 2017 total solar eclipses sweeping across US
• 4 Boeing's Starliner spacecraft is 'go' for May 6 astronaut launch
• 5 Russian cosmonauts make quick work of space station spacewalk

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

Program Manager, Teaching & Learning Initiatives

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

Sydney Horizon Educators (Identified)

Deputy Social Media Producer

Associate Professor, Occupational Therapy

How Long Would It Take To Travel A Light Year

Using the fastest man-made vehicle, NASA’s Juno spacecraft, which travels at 165,000 mph (365,000 kmph), it would take 2,958 years to travel a light year. A light year is equivalent to about 5.88 trillion miles (9.46 trillion kilometers).

Traveling at the speed of light would be the fastest way to cover vast distances in space, but current technology makes it impossible for humans or even our most advanced spacecraft to reach this speed.

Can people match the speed of a light year?

According to Einstein, it is impossible to match the speed of light. It is because light is the fastest thing in the universe, traveling at 186,000 miles per second (300,000 kilometers per second). There is not one thing that we could invent that could even match a fraction of how fast light travels.

Some scientists have theorized that a new type of engine, called a warp drive , could potentially allow humans to reach the speed of travel required to match the speed of light. However, even if future spacecrafts were able to achieve this level of propulsion, it would still take thousands of years to travel from one star system to another.

Despite the challenges, scientists continue to study space travel at faster-than-light speeds, as they are optimistic that one day we will be able to explore the vast reaches of our universe and even discover life on other planets.

For now, it would take many thousands of years to travel a light year using current technology. However, scientists remain hopeful that one day we will be able to explore the far reaches of space and perhaps even discover other life forms in distant star systems. Until then, we can continue marveling at the

Related Posts:

• How Long Would It Take To Get To Venus?
• How Long Would It Take To Get To Saturn?
• How Many Years Is A Light Year?
• What Is The 33-Year Cycle?
• How Far Can We Travel In Space With Current Technology?
• How Long Does A Solar Eclipse Last?

Fastest Things in the Universe: Top 5 Cosmic Phenomena With Immensely High Speed

As we gaze at the night sky, imagining the universe as a calm and unhurried place is easy. In reality, however, the cosmos is home to things that move fast. Here are five of the fastest things and events humans have observed in the universe.

1. Cosmic Expansion (Faster than Light)

Scientists agree that the universe is expanding. However, the universe's expansion is not in a way that fills up 'empty space.' Instead, it is 'space' itself that is expanding.

The laws of physics suggest that two objects cannot move faster than the speed of light relative to each other. Still, there is no restriction on expanding the actual space they move in.

In principle, the furthest we can observe in the universe is known as the ' cosmological horizon ,' beyond which light cannot yet reach us during the universe's lifetime. Although we can never see it, the cosmos still exists beyond this limit, and the invisible parts of the universe recede from us at a rate more significant than the speed of light. Unfortunately, we can never see those parts of the universe, so we cannot be sure just exactly how fast they are receding.

2. Light ( 299,792.458 km/s )

Light, or the entire electromagnetic spectrum, is the fastest 'physical' thing in the universe. According to scientists, the speed of light is also the universe's self-imposed speed limit.

Nothing can move faster than the speed of light. This is because objects with mass need energy to accelerate them, and the laws of physics suggest that infinite energy is required to accelerate a mass up to light speed. What is even more confusing is that objects traveling faster than light would have to be traveling backward in time.

READ ALSO: Faster Than Speed of Light: Can Tachyon Really Travel Back in Time?

3. Gravitational Waves ( 299,792.458 km/s )

All particles without mass travel at the speed of light, as do the force fields like the weak and strong nuclear forces and the gravitational force. The same goes for gravitational waves, or the ripples in the fabric of space-time created by moving mass.

The first direct detection  of gravitational waves was announced in 2016. Since then, the study of these cosmic ripples has helped astronomers increase their understanding of the universe.

4. Cosmic Rays ( 299,792.4579999 km/s )

Cosmic rays hold the record for ordinary matter traveling at high speed. However, they are not rays but subatomic particles generated in the most powerful events in the universe, such as galaxy mergers and hypernovae , the explosive deaths of extremely big stars.

The fastest cosmic ray yet detected traveled so close to the speed of light that it had the same amount of energy as a medium-paced cricket ball, even though it was a fraction of the size of a single atom.

5. Blazer Jets ( 299,492.666 km/s )

The speed record for large chunks of matter, as opposed to subatomic particles, is held by the 'jets' observed in ' blazars .' A blazar  is a galaxy with an intensely bright central nucleus that contains a supermassive black hole, much like a quasar.

Black holes at the centers of these active galaxies emit vast amounts of energy, which is funneled into jets by a dense, highly magnetic  accretion disk. Jets observed so far move at about 99.99 % of the speed of light.

RELATED ARTICLE: What Is the Speed of Gravity? Do Gravitational Waves Travel Exactly at the Speed of Light?

Check out more news and information on Speed of Light  in Science Times.

Most Popular

Plato’s Long-Lost Grave Found Using AI To Decipher Herculaneum Scrolls; Greek Philosopher Had Been Sold Into Slavery: Report

Influenza Shows Highest 'Pandemic Potential' Among Ranked Pathogens, Study Reveals

UFOs Piloted by Spiritual Entities? Fox News' Tucker Carlson Makes Bizarre Claim, Suggests That They Do Not Behave According to Laws of Science

NASA Spacecraft, Russian Satellite Had a Near-Miss Encounter That Was Closer Than Scientists First Thought

Latest stories.

76-Million-Year-Old Fossil of Gigantic Great White Shark Relative that Lived Among Dinosaurs Discovered in Mexico

2 NASA Astronauts Arrive To Serve As Test Pilots for Boeing’s Starliner Capsule a Week Before Its Mission Launch

Bird Flu Outbreak in Dairy Cows Is Extensive; Traces of Virus Found in 20% Commercial Milk Sample

Weird Animal Diet: 5 Species With Unusual Food Preferences

Malaria Mutation Makes Plasmodium falciparum Invisible in Rapid Test, Contributes to 80% False Negative Test Rates

Subscribe to the science times.

Sign up for our free newsletter for the Latest coverage!

Recommended Stories

Small Dark Formations on the Red Planet's Surface Appear Like Spider in Photos Captured by ESA's Mars Express

Citizen Scientists Identify New Sample of Over 1,000 Hidden Asteroids in Hubble’s Archival Data

NASA Engineers Successfully Repair Voyager 1 After 5 Months of Troubleshooting 15 Billion Miles Away

NASA Releases Stunning Concept Art of Lake Lava Loki Patera on Jupiter's Io Moon

We couldn’t find any results matching your search.

Please try using other words for your search or explore other sections of the website for relevant information.

We’re sorry, we are currently experiencing some issues, please try again later.

Our team is working diligently to resolve the issue. Thank you for your patience and understanding.

News & Insights

Trading as Fast as Lightning

Exchanges can trace their origins back to the  Middle Ages . Since then, however, technology has transformed the global capital markets, and the speed of trading has accelerated with the adoption of computers to trade, mostly over the last 50 years. Today, quotes and trades travel over microwaves, lasers and optic fibers – often at close to the theoretical speed of light. 

Fiber optics, microwaves and lasers replace trading pits  

In today’s modern markets, orders, confirmations, quotes and trade data move digitally along a combination of cable, microwave, millimeter wave and, most recently, laser.

As with most aspects of trading, there is a tradeoff with each.  

Chart 1: Different data transmission technology

Fiber is the most reliable and has the most bandwidth. Fiber optic cables work by sending light pulses along fiber or glass tubes. Because light slows down in the glass, fiber is “slower” than the alternatives, and it’s best to use it if you need to send a lot of data or detailed data.  

In contrast, microwaves — millimeter waves and lasers — all move through the air. That makes them all faster than fiber but are more prone to signal disruptions due to natural events, such as the passage of clouds, rain, mountains. This phenomenon makes them  unreliable for a split second or hours affecting market liquidity .  

The curvature of the Earth is also a problem. Wireless transmitting requires frequent signal towers high enough to see over mountains and around the globe. In fact, the curvature of the Earth alone makes the Earth slope  100 feet every 25 miles.   

Furthermore, wireless transmissions can’t hold as much data as fiber, and the signal tends to fade faster (needing more “repeater” stations to amplify and resend the signal. However, that is where tradeoffs between laser and radio waves begin.  

Table 1: Benefits of different types of data transmission technology

Source: Nasdaq Economic Research, A Comprehensive Review on Millimeter Waves Applications and Antennas;  Millimeter Wave Propagation: Spectrum Management Implications; Fiber Optic Association ;  Nasdaq Co-Location Services, Anova , Wall Street Journal, Optics Express  

*Anova system uses a combination of laser and mm wave

Both microwaves and millimeter waves are a type of radio frequency signal. Radio signals travel pretty close to the speed of light and around 50% faster than light can move down a fiber cable, so switching to using microwaves can really decrease how long it takes to find out when prices and markets elsewhere have changed (also called “latency”).

The main difference between microwaves, millimeter waves and lasers is their frequency and wavelength. This requires us to get into a little physics.

Frequency measures the number of waves that pass a point in a second; a higher frequency means more waves move in that second. Wavelength tells us how much energy the signal can carry; a larger wavelength has less energy and carries less data, while shorter wavelengths have more energy and carry more data. We can hear this with sound waves. Low tones have long wavelengths and sometimes are hard to hear. High notes have higher frequencies, and some can hurt our ears. 

However, we are talking about electromagnetic waves – some of which we can see. Chart 2 shows how the wavelengths change and where they are useful.  

Chart 2: Electromagnetic spectrum

Overall, the main latency (speed) difference is between wireless and fiber. Capacity (or bandwidth) then differentiates each of the technologies, too, with higher frequency, giving millimeter waves an advantage over microwaves, but at the cost of shorter distances between antennae.  

What about satellites?  

We’ve all heard of satellite TV. Why don’t we trade with satellite messages? 

It turns out the distance from Earth to a satellite and back matters – and is longer than around the surface of the Earth. However, some say  low Earth orbit  satellites could  work for long distances .  

Chart 3: Satellites vs. microwave

Source: A Bird’s Eye View of the World’s Fastest Networks , 2020  

How much does time matter?  

Even a very short distance, like the distance from Nasdaq to Secaucus (where dark pools sit, pegging peg prices to primary quotes), can matter to certain traders.  

• Via fiber, the theoretical fastest speed is around 162us (microseconds).  
• Via wireless, that falls to  only 89us . 

That might not seem like much (it is, after all, a fraction of one-thousandth of a second). But even in an Olympic race, a split second can be the difference between winning and second place – here, it might mean completing an arbitrage or being legged and exposed to losses.  

Think of this a different way: There are about 35 million trades a day and only 23.4 million milliseconds during market hours. In short, microseconds can matter. And that’s before we discuss how most activity happens in 1% of the microseconds in the day. That’s why traders doing strategies where latency is important choose to use wireless technology. And the advantages and disadvantages of each are why millimeter wave, microwave and lasers exist.  

But it’s also important to remember that to a human optic fiber is very fast, too – and it’s accurate and can handle large bursts of activity with less backlogs. That’s why it’s used for the SIP.  

Just like for the past hundreds of years, it’s likely that the  race for lower latency  will continue. However, the reality is that if you’re using wireless now, you’re already pretty close to the theoretical limits of the speed of light, and you’re aware of the tradeoffs you’re already making to get there.  

Nicole Torskiy, Economic Research Senior Specialist, contributed to this article.   

Related Articles

Latest articles.

This data feed is not available at this time.

• Type a symbol or company name. When the symbol you want to add appears, add it to My Quotes by selecting it and pressing Enter/Return.

These symbols will be available throughout the site during your session.

Your symbols have been updated

Edit watchlist.

• Type a symbol or company name. When the symbol you want to add appears, add it to Watchlist by selecting it and pressing Enter/Return.

Opt in to Smart Portfolio

Smart Portfolio is supported by our partner TipRanks. By connecting my portfolio to TipRanks Smart Portfolio I agree to their Terms of Use .

Ultrafast laser-powered 'magnetic RAM' is on the horizon after new discovery

Researchers have found an elemental physical interaction between light and magnetism that might lead to the next generation of computing memory.

Scientists have discovered a new mechanism in which a concentrated laser beam can change the magnetic state of a solid material. The finding could one day be harnessed in ultrafast computing memory, the researchers say.

The scientists formulated a new equation that describes the link between the amplitude of the magnetic field of light, its frequency and the energy absorption properties of a magnetic material. The scientists published their findings in a study on Jan. 3 in the journal Physical Review Research .

The equation is "completely new and also very elemental," study co-author Amir Capua , a physics professor at Hebrew University of Jerusalem, told Live Science.

Although the discovery builds on the field known as "magneto-optics," this represents a new paradigm because scientists didn't previously understand that the magnetic component of a rapidly oscillating light wave can control magnets, he said. The equation describes the characteristics of this interaction.

Computer memory uses miniature electromagnets that are magnetized with voltage to enable the binary states of "on" or "off" to encode data, which are read and reinterpreted by a processor as 1 or 0. 

The most common computing memory, like those found in laptops or phones, comes in the form of dynamic random access memory (DRAM). This is volatile, meaning when power is switched off, all data held is lost, but it's easier to engineer, uses common materials and has low error rates — and those few errors are easy to detect and fix.

The new finding is more relevant for a technology called magnetoresistive random access memory (MRAM), which is a non-volatile memory more commonly used in spacecraft as well as military and other industrial applications, according to MRAM-info .

Sign up for the Live Science daily newsletter now

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

Related: 'Universal memory' breakthrough brings the next generation of computers 1 step closer to major speed boost

Interaction between a magnetic material and radiation is well established when they are in equilibrium, but less is known about this relationship when they are not in equilibrium. It's also an area that overlaps with the weird laws of quantum mechanics , which are being harnessed to build quantum computers.

"We've arrived at a very elementary equation describing this interaction. It lets us completely reconsider optical magnetic recording and navigate our way to a dense, energy-efficient, cost-efficient optical magnetic storage device that doesn't even exist yet," Capua said.

Previous efforts to use the magnetic component of a light beam to flip a magnetic bit in this way were not effective, Capua said. But the new equation could help researchers to successfully incorporate the mechanism, he said.

In the far future, this technology could lead to MRAM components that are faster and more efficient than today's state-of-the-art RAM units, he added.

— World's 1st graphene semiconductor could power future quantum computers

— Computing 'paradigm shift' could see phones and laptops run twice as fast — without replacing a single component

— World's 1st PC rediscovered by accident in UK house clearance nearly 50 years after last sighting

Optical cycle times (the time for an optical electromagnetic wave to complete an oscillation, in megahertz) in the technology could be a million times faster than in conventional memory. Electrical cycle times operate on nanoscale timescales (a second is 1 billion nanoseconds) whereas typical optical beams work in picoseconds (a second is 1 trillion seconds). 

It may also one day lead to quantum memory for quantum computers, in which a beam of light can fix a magnetic bit in neither 0 nor 1 but a superposition of the two states — much like how qubits work in quantum computers . Even though that's beyond the precision engineering of today, Capua said his team's findings could lead to the discovery of materials that could one day be used in such technology.

It can also make digitized memory systems more energy-efficient by giving the device more control over the strength and duration of the light beam and its effects. "The duration of the optical beam and its energy can be chosen to reduce the writing power. Obviously, when the device is idle it doesn't consume any energy since magnetic memories are nonvolatile," he said.

Drew is a freelance science and technology journalist with 20 years of experience. After growing up knowing he wanted to change the world, he realized it was easier to write about other people changing it instead. As an expert in science and technology for decades, he’s written everything from reviews of the latest smartphones to deep dives into data centers, cloud computing, security, AI, mixed reality and everything in between.

Tired of your laptop battery degrading? New 'pulse current' charging process could double its lifespan.

China develops new light-based chiplet that could power artificial general intelligence — where AI is smarter than humans

Traces of hallucinogenic plants and chile peppers found at Maya ball court suggest rituals took place there

Most Popular

• 2 Giant, 82-foot lizard fish discovered on UK beach could be largest marine reptile ever found
• 3 Global 'time signals' subtly shifted as the total solar eclipse reshaped Earth's upper atmosphere, new data shows
• 4 'I nearly fell out of my chair': 1,800-year-old mini portrait of Alexander the Great found in a field in Denmark
• 5 NASA reveals 'glass-smooth lake of cooling lava' on surface of Jupiter's moon Io
• 2 China green-lights mass production of autonomous flying taxis — with commercial flights set for 2025
• 3 George Washington's stash of centuries-old cherries found hidden under Mount Vernon floor
• 4 5 catastrophic megathrust earthquakes led to the demise of the pre-Aztec city of Teotihuacan, new study suggests
• 5 Scientists find one of the oldest stars in the universe in a galaxy right next to ours