Is Interstellar Travel Possible? (Time Dilation & The Speed of Light)

Is Interstellar Travel Possible? (Time Dilation & The Speed of Light)

How will humans colonize the stars beyond our own solar system? Research in space travel has only recently begun to tackle this problem. But almost 100 years ago, Albert Einstein made some revolutionary
claims about the types of challenges that await those who travel at high
speeds across the cosmos. Particularly with regards to the way they experienced time. While most people view time as a constant, Einstein’s special theory of relativity proved that the passage of time is affected by how fast an object moves relative to its
surroundings. The faster one travels through space, the more one’s perception of time changes. This phenomenon is called: time dilation. If an astronaut can travel at close to the speed of light, time will pass much more slowly for her. When she returns to Earth, her friends will have aged more than she has. For example, if near lightspeed travel were possible, an astronaut could travel to Alpha
Centauri, our closest neighboring star system, 4.37 light years away. Moving at 99.1 percent of the speed of
light, it would take 8.82 years to get there and back—as measured by an Earth observer. However, due to time dilation, the astronaut would experience a round-trip journey of just over one year. Einstein also theorized that the speed of light represented a fundamental speed limit in the physical world. According to
Einstein’s theory, objects with mass cannot exceed the speed of light because
they would require an infinite amount of energy to do so. This is true for
everything from spaceships to neutrinos. In spite of this limit, scientists
continue to ponder the possibilities of faster than light travel. The first example of faster than light speeds in popular culture, occurred in the television series Star
Trek. On the show, spaceships generated a fictional subspace bubble, by surrounding themselves in a warp field, in order to exceed the speed of light without experiencing relativistic effects like time dilation. Using this technology, the Starship Enterprise was able to travel billions of kilometers in a matter of seconds. For those of us hoping to seek out new life and new civilizations, Scientists have hypothesized that interstellar travelers could be detected. In Space, photons can cause drag and because a fast-moving spaceship would encounter so many more photons than a ship moving slowly, the ship would generate an energy signature that would be both visible in
the infrared spectrum, and detectable by us. This means that alien civilizations—if
they exist—would also be able to detect us traveling at this nearly light speed. Outside of science fiction, the fastest we’ve ever flown in space was during the Apollo 10 mission, which reached speeds of about 39 897 km/h. At that speed, it would take 165 000 years to reach the nearest star system. This suggests that with conventional propulsion technology, humanity will never reach even nearby stars. The problem with current
spacecraft technology is that the propellant they carry with them, and use
for thrust, has mass. Interstellar space craft require a lot
of propellant, which makes them heavy, which requires more propellant, making them heavier and so on. However, some of physics’ brightest minds, including Stephen Hawking, believe that new technologies are making interstellar
travel a real possibility. In the latest initiative launched by the Breakthrough Prize Foundation, Hawking and his team pledged $100 million dollars to
send tiny ships to our closest neighboring star system, Alpha Centauri. They claim
that lasers are now advanced enough to help launch interstellar space probes. Researchers can currently build phased laser arrays. These arrays are made up of many relatively modest laser amplifiers that can synch up to act like a single
powerful laser, kind of like the Death Star Laser… …but not all death-like. Eventually, the scientists want to build a 50-70 gigawatt laser array that is ten
kilometers by 10 kilometres in size. Launched into orbit around Earth, the array could shoot light at a very small spacecraft, about the size of a saltine
crackers and the weight of a paper clip that’s equipped with the one metre wide
sail. The scientists calculate that this would
accelerate the tiny probe to more than 25% of the speed of light after about 10
minutes of illumination. At that rate, it could reach Mars in 30 minutes and Alpha Centauri in about 20 years. The laser array could launch roughly 40,000 relativistic wafer-sized probes per year, carrying sensors, cameras, communications devices, power, and other systems. Some challenges remain. It would take the same array about 2,200 years to propel a fully loaded space shuttle to Alpha
Centauri. A much larger array would be needed for a human interstellar trip in
the distant future. But with the emergence of these new propulsion technologies, galactic travel might be closer than we previously anticipated. Thanks for watching! Want more Thought Café and Popular Science? Click to watch our last collaboration. And make sure to subscribe so you never miss a new video!

100 thoughts on “Is Interstellar Travel Possible? (Time Dilation & The Speed of Light)


  2. hold on a second. If Alpha Centauri is 4 light years away surely if you travelled nearly at the speed of light it would take 8 years for the trip? Not the 1 year it states?

  3. But when you move at 25% of light speed in a tiny ship, how are you going to slow down???

    Those little probes where just intended to do an fly by on the solar systems but a human ship has to land on the planets there.

  4. They wouldn't be able to be back though. So if we in theory had infinite energy could we go faster than the speed of light?

  5. I like the fact that the spaceship used here is the Kestrel from FTL.

    Were the hell did they get that from?

  6. is not the worry of going faster then speed of light, as you approach speed of light, distances shrink thanks to relativity. when travelling like 99.99% speed of light, alpha centari is no longer 4.3 light years, but a near 0.06 light years, to the perspective of the crew. Meaning to the crew, it would take 0.06 years to arrive, but to people viewing on earth, still takes 4.3 years. The ship crew could fly there and turn around and fly back in 0.12 a year, and the people on earth would age 8.6 years.

    The problem is getting to that speed and the dangers it poses to matter, as you near the speed of light, takes much much more energy and thrust to go faster. Pretty much you are not going any faster, your thrust and energy is just shrinking the universe from your perspective. There can be problems associated with that. You could have a huge fusion reactor aboard that can propel your ship super super fast past 99% speed of light, one small minute piece of dust in your way would explode your ship to dust. A rock would disintergrate your ship and you wouldn't even feel it. Simple radio waves, infrared, light waves start turning into ultraviolet, xrays, and gamma rays to your perspective and will kill you onboard. Then you have to slow down when you get there. you cannot land anywhere at those speeds. You'll need exactly the same amount of thrust going in opposite direction to slow back down. We are not safe for +99% the speed of light travel.

  7. Einstein said it is impossible,just because he said it,it must have been true?How about he tried to 'hush hush' posibility of it?They also told you can't teleport people,Philadelphia Experiment.

  8. Just doing some math of the distances covered by the warp drive. It seems that Warp Factor 1,2 and 3 is that number cubed multiplied by the speed of light. Warp 1 = 1 ^3 = 1  , Warp 2 = 2^3 = 8 , Warp 3 = 3^3 = 27….however if we get to Warp 9 then 9^3  = 729 not 834  ???  So does anyone know how these figures are calculated ?

  9. Your just giving excuses for why scientists are too fucking lazy to make the speed of light possible for humans you find a fucking problem in the possibility you fucking fix it like the more gas thing then isn't it possible for us to make a fuel that's actually gas and not a liquid you pore into the aircraft

  10. Private companies like Space x are the future guys let’s just face it NASA will never be able to support enough money for interstellar travel as quick or efficiently as a private company that already has the funding. (This is just my opinion though; tell me what u guys think below ?)

  11. Hi Thought Cafe! Just seen this video, really love it!
    May I ask you something? How do you make your animations?
    Best wishes and a wonderful day, Life is Physics

  12. Of course…. a star gate…. only I didnt picture normal lazers working or a cup shape… to each his own I guess. But it would take a shuttle you say 2200 years was it…. too long…. we will need anti matter and perhaps that star gate will come in handy after all. But it would seem we are unto something…. we realize we need some kind of large station to propell a small ship. Ive studied this concept out with an anti matter star gate….. the problem is the exceleration would crush the passengers….. it either has to be a slow steady acceleration or we need to invent something to cope with the ecceleration. ……. having a steady acceleration will work but this has its own host of problems… how to do it at such long distances. I envision having a series of star gates around the solar system like a giant partical accelerator.

  13. …interstellar travel constant acceleration (Trappist-1: 1g)… passenger climb in space-elevator to the "Aquarius-1" (starship with 1000*100*100 mts sizes and…), awaits them in asteroid Toutatis at geostationary orbit… THE SHIP TAKEOFF►…at destination passengers disembark: an engineered Terraformed planet from the red dwarf Trappist-1 cool star.

  14. So we’re just going to act like Bob Lazar didn’t tell us exactly how to create a ship that is capable of interstellar travel? Youtube Bob Lazar watch the his full 40 minute video promise you wont regret it

  15. Sooo a few questions? If the laser can move the sail? What’s the laser gonna do to the ship and it’s contents that’s behind the sail, because it has to pass threw it to the sail. Also if it’s traveling 25% the speed of light, hows the probe gonna slow down once it’s to its destination in 20 years?

  16. I'm sorry, but this makes no sense to me. How about the outside universe that is moving faster then light away from us so that we can't even see them? And how can you tell how "fast" something is moving anyway, what is your reference that your comparing your speed to??

    What if 2 planets are moving towards each other at 3/4 the speed of light? If your standing on one plant an have your reference there, the other planet would be moving towards you at 1.5 speed of light. Right??

  17. Yea even if light speed were possible. We couldn't do it cause no possibility of steering. Eventually you'd run into a star or planet. Just cause your going at light speed doesn't mean your immune.

  18. Well, that laser wouldn’t work as well for human spaceships. Theoretically speaking, even if we made a laser array so big that we can go to mars, how would we get back?

  19. Informative, great video after watching a bit disappointed I can't take a trip in the Enterprise D to look around even our own solar system.

  20. Good animation but one small problem, sure a 70 gigawatt flashlight may be capable of thrusting an object forward but is there any known substance that could take being bombarded with 70 gigawatts of power, let alone something with less mass than an apple? Not only that how could you steer such an object let alone slow it down again to check out a planet?

  21. They don’t consider that you have to slowly increase the speed with humans on board and there’s a limit for electronics too. And when you’re half way there, it starts to slowly decelerate. That probably at least doubles the light speed travel time. You can’t just start right at light speed. You don’t want the acceleration for people to be more than 1x earth’s gravity so people could live on the rear of the ship, with many floors, like a tall building. And then live on the “ceiling” when it starts to decelerate. I’m sure there’s a lot I don’t know too.

  22. if i go at the speed of 2c would i calculate the the time experienced like sqrt(1-(2c)^2/c^2)^2 to make it a real number ? or

  23. Using such a laser Array is quite brilliant, but the power required is still a damn sight more than simply cycling several sections of a space freighter in a sequence to their electromagnetic fields phase. "Think Rail Gun" Having at any given time, most of the bulk of the freighter tied electromagnetically together as a main mass, So that a section which is switched out of phase can be repulsed to accelerate forward and towards the leading section/s, And yes acceleration can be quite intense initially, but once maximum velocity is attained, no more energy used, "acceleration/deacceleration energy can be obtained via solar arrays" only directional navigation will be needed, and even with navigation, much the same principles can be applied, so use of energy would be at minimal.
    To slow down the freighter, the whole process is to simply accelerate the sections backwards.. It seems absurd, but with the right timing acceleration BTW can be demonstrated by using a toy train "via their shunts or connections removed and then first and last sections tied together via a flexible tether traced through the mid sections so that each section is allowed efficient acceleration" and yes it's all in the timing, that has the whole damn thing with an amazing acceleration..

  24. This information is on the Book of Stephen Hawkins "A brief History Of Time" and more, I read the book myself.

  25. it seems to me that, regardless of engineering challenges around propulsion and acceleration, there is also a practical limit to how fast we’d WANT a probe to travel before the effects of Time Dilation get in the way of obtaining results. maybe someone better at physics can correct me, but it seems that you’d want to identify a top end speed that is just right to allow the scientists asking the question to get answers before they die. if the craft is too slow, it simply takes too long to get there, so the scientist dies before a message back is ever sent. if the craft is too fast, there is too much time dilation, so even though the craft gets to the destination very fast (in its frame of reference), the time elapsed on earth is very great due to dilation, so the scientist is also dead before receiving a message. some rough calculations look to me like this optimum speed is about 70% of the speed of light.

  26. This laser propulsion system seems awesome!! I hope so much that someone, public or private, will try to built this tiny exploring ship as soon as possible!!
    This way we could really explore, at least visually, the universe around us. 😀

  27. hello fellas!! What about making a whatsapp group of all knowledge enthusiasts from around the world? I think it would help us all in many different ways and we'd be able to communicate with like minded ones with ease. So reply your ideas on this thing and we would then think how to proceed further. So i think its a great idea and would help us all. Seeing forward to your replies.
    Have a good day, everyone..!!

  28. So objects in space experience sl9wer time be sure of lack of gravity..and less stress on the question if everything is weightless in space shouldn't a proton and a rocker have the same footprint in said space..

  29. Why don't we just make a super smart AI, like smarter than every human that ever lived combined, and then just tell it "invent travel at the speed of light" or "invent teleportation"

  30. 20 years ?? if it doesn't get destroyed
    Also what would be the point if it doesn't have a camera or something

  31. If we to travel much faster than light, our flesh seems to be the final barrier. But the next dimension could be to travel by spirit without boundaries at all, and at destination re materialize our body

  32. 2:54 I thought with our current technology it would take 80 thousand years to get to Alpha Centauri

  33. If laser experiment succeed for example: as u said it can reach more than 25% of light speed, what about the material, is it gonna bear that drag which is 25% more? Also will that laser radiation effect ozone layer????


  35. I cant understand the theory of relativilty… if someone could travel in the speed of light and I told him to go back in forth in the speed of light for 10 seconds it would still be considered 10 seconds of his speed of light time and 10 seconds of my normal time, so how the hell would he be younger than me???? Time is time whether you move freaking fast or not 10 seconds is 10 seconds right?? If light travel from the sun travels 8 minutes to reach earth then someone who travels in the speed of light were asked to go travel around the space for 8 minutes and I timed him on my watch he will not return in 1 seconds right??? He will be returning in 8 minutes!! He just move so fast he was able to cover so much distance in 8 minutes of OUR time(meant him and me) so what the hell is going on with Albert einstein?? Dont show me some freaking physics mathematical solution here, let's talk for real.

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