How to travel faster than light

How to travel faster than light

You don’t have to be much of a science enthusiast
to have heard that you can’t go faster than light. Well, I’m going to tell you at least one
way that two real, honest-to-god objects, that exist in our universe, can move away
from one another faster than the speed of light. Now, don’t get super excited. I’m talking about ways this can happen without
breaking the laws of physics. To be ultra clear, I’m not talking about
something that will lead to this. Or this. Or this. We’re gonna have to go right to- ludicrous
speed! Ludicrous speed? Sir, we’ve never gone that fast before! I mean, I totally want to know how to go ludicrous
speed. But, unfortunately, and I hate to have to
tell you- these are all fiction. So, if it’s possible to go faster than light,
what exactly do I mean by the speed of light? I mean the speed of light in a vacuum in a
location where spacetime is not bent or changing. Under those conditions, the speed of light
is about 186,000 miles per second or, for the metric crowd, precisely 299,792.458 kilometers
per second, or fast enough to circle the globe 7.5 times in a single second. Light is like really, really, fast. When physicists use the symbol “c” to
denote the speed of light, it’s this speed that they’re talking about. So, how can you go faster than light? I can think of three examples, although they
all aren’t quite what you probably think. The first is cheating. When light enters a transparent medium like
water or glass or something, it slows down. In glass, light travels at about two thirds
the speed it does in a vacuum. In water, it’s about three quarters. You can see the effect of this change in velocity
by simply sticking a pencil in a glass of water. The pencil doesn’t really bend, but appears
to because of this effect. While light slows down in a transparent medium,
other particles do not. That means that if you shoot an electrically
charged particle like an electron or a muon traveling at near the speed of light at that
same medium, the charged particle travels faster than light in the medium. Cool, huh? When this happens, the charged particle emits
blue light like you see here. This light is called Cherenkov light after
its discoverer, Pavel Cherenkov. Explaining just how Cherenkov light is formed
is, well, tricky- and maybe I’ll make a video about it. But the blue light you see here proves that
it is possible for objects to move faster than light in a transparent medium. In this example, the light is formed when
radioactive material emitting highly energetic particles is immersed in water. It’s all way cool. So that’s maybe a cheat. Particles move faster than light, but it’s
not because particles got faster, but because light got slower. Are there other examples? Well there is another instance of information
traveling faster than light which I’ll mention only briefly and this involves a topic called
quantum entanglement. Quantum entanglement is a category of quantum
mechanics, which is known for its bizarre predictions- cats both alive and dead and
all that. It is not possible to explain it in detail
here. That would actually require not just one video,
but an entire series, but here I can give the highlights. In quantum mechanics, probability rules. Anything that is possible can happen, governed
by the probabilities of that particular situation. As an example, a subatomic particle can have
a spin of plus or minus. You can’t know which of those spins it has,
until you actually measure it. It’s important to understand that this isn’t
a simple case of ignorance. It’s not that the spin is plus or minus
and you just don’t know. It’s both plus and minus and it becomes
plus or minus when you measure it. Now suppose you take two particles and set
them up so that they have opposite spins. If one is plus, the other is minus, and vice
versa. When physicists do this, they say that we’ve
entangled the two particles. You can’t know in advance which particle
is plus and which is minus. You then separate the two particles by a large
distance and look at one of them. Say you find that it’s a plus spin. If you look at the other particle, you’ll
find it’s a minus spin- every single time. And this will be true even if you look at
the second particle so quickly that you see it before a signal arrives from the first
particle traveling at the speed of light. Einstein called this a “spooky action at
a distance” and it says that the information in quantum mechanics can travel faster than
light. Nobody understands this, but it’s well established
and it’s just a true effect. So that’s a case of something traveling
faster than light, but you can’t use it to send a message and it’s still not the
same as an object moving faster than light like the Starship Enterprise or the Millennium
Falcon. So let’s talk about a third situation where
things actually can travel faster than light. And that’s the expansion of the universe. Now I should be cautious. When you hear people saying “the universe
expands faster than light,” it’s obviously a statement that requires some care, because
your first question should be “what does that mean?” Well, obviously the universe can’t mean
our planet, our solar system, or even our galaxy. After all, none of them are expanding much,
if at all- and certainly not at the speed of light. In 1929, American astronomer Edwin Hubble
combined measurements taken by several people and found that distant galaxies are moving
away from Earth and, the further away they are, the faster they’re moving. This is now understood to be evidence that
the universe is expanding. Using modern numbers, a galaxy a megaparsec
away is moving away from us at 70 kilometers per second. A megaparsec is million parsecs, which is
3.26 million lightyears by the way, but astronomers use megaparsecs, so I will too. If a galaxy a megaparsec away is moving away
at 70 kilometers per second, a galaxy two megaparsecs away is moving away at 140 kilometers
per second. Three megaparsecs means 210 kilometers per
second, and so on. So we know that the speed of light is 300,000
kilometers per second, so we can figure out how far away we have to go to have a galaxy
moving away from us at the speed of light. That turns out to be 4,296 megaparsecs or
just shy of 14 billion lightyears. This means that the surface of a sphere, centered
on the Earth, and with a radius of about 14 billion lightyears is moving away from us
at the speed of light. It also means that bigger spheres are moving
away from us at faster than light. A sphere with a radius 28 billion lightyears
across is expanding at twice the speed of light. So, what does this mean? Does it mean that there are galaxies moving
away from us at speeds faster than light? Yeah. Yeah, it does. Of course, it also means that we can never
see them. If objects move away from us faster than light,
then that means that light emitted by them never get to our eyes. So, we can never see the light emitted by
anything currently further away than 14 billion lightyears. The true number is a little different because
of details of how the expansion speed has changed over time. To get the number right means we have to take
a more nuanced approach than I’m doing here, but those details don’t change the big message. It’s also incredibly important to be super
careful about how we envision it. The reason is that it’s not precisely accurate
to say that these galaxies are moving away from us faster than light. Yes, the distance between us is increasing,
but it’s because space is expanding, not because the galaxy is moving away in space. It’s kind of like putting a rubber duck
in a river. The duck isn’t moving as far as the water
is concerned. It’s the water that’s carrying the duck
away. Or like drawing dots on a balloon that’s
inflating. The dots don’t move on the surface of the
balloon, but the distance between them is increasing because the balloon is stretching. So it’s entirely fair to say that there
exist galaxies that move away from us faster than light, but only in the sense that the
expansion of space makes it happen. Those galaxies are stationary, or at least
nearly stationary with respect to their own space. They’re not moving through space. I’ve described three examples of the phenomenon,
but none of them are something that those of us who hope to explore the cosmos would
like to see. According to our best understanding of the
laws of physics, light obeys the ultimate speed limit. Now, our understanding of the rules that govern
the universe are constantly improving and it’s okay to hope that we’ll discover
some new principle that makes it possible to go faster than light. Although unlikely, it may be that we will
eventually find some new phenomenon that changes our prospects for exploring the galaxy, and
then, and only then, we will have finally figured out a way to go- LUDICROUS SPEED! People say that it’s impossible to go faster
than light, and, as a practical matter, it’s probably true. But we’ve learned in this video about a
few ways in which we can at least kind of break that rule. So now you have some tidbits to use at your
next cocktail party. You’re welcome. If you like what you’ve seen, remember to
be sure to like, share and comment. We want to know what you think. And, as always, remember- physics is everything.

100 thoughts on “How to travel faster than light

  1. What about if the speed of light changes if spacetime is bent by gravity? How sure are we that c is a constant? Could we send a probe that measures the speed of light near greater gravitational forces? Is the universe really expanding or is it that our perception of spacetime is corrupted by gravitational forces (Like 2 vehicles breaking on a highway but from different initial speeds, making the fastest one still getting further even though both are decelerating at the same rate.)? What if just before the "Big Bang" speed of light was infinite and time was nil? I believe that gravity might speed up time and slow down c when G gets higher.

  2. EXAMPLE #4: shoot a laser, radio wave, electron, or other similar particle that encodes data within it's beam (like a DVD/CD drive does in a computer) off of a VERY FAST moving object such as an asteroid or NEXT GEN space shuttle going around 50,000 MPH… then, that light, wave, data, etc. will travel faster than the speed of light! And if theories are correct, then you'll be able to send data back into the past. Warnings can always be very helpful to humanity; just think about the possibilities! <this example is a theory; do you think it could work and if not, why not (explain the science if you can, to back up your doubt)?

  3. dr.don, if the universe is expanding, what is the science behind it, and could it be manipulated for transportation.

  4. How to travel faster than the speed of light:
    1. Accelerate up to the exact speed that light is traveling.
    2. When specific light speed is reached…..give it a little more gas!

  5. What would be observed if two objects were moving at very high speeds towards each other? Would that make relative velocity greater than the speed of light?

  6. The question in my mind is how fast is the other side of the earth moving away from me per year. And if we measure the diameter of the earth in a billion years, will the yard stick we use to measure the earth also have grown proportionately, so the measurement will be the same,

  7. would it be possible to use the expansion of space to generate energie? Like: tie a robe at two points at the balloon and use the tension that build up as engergy source? ( Even if the space doesn't expand a lot it is still energy and if you are traveling in a space ship: a little energy at a time can make you go really fast)

  8. As it relates to travel beyond our solar system and out into the universe, here's a bit of a depressing thought; If somehow we were able to travel at 100 times the speed of light it would still take over 1 month to complete a round trip to our closest neighboring star, Proxima Centauri. At 100x light speed it would take 250 years to reach either the center of our galaxy or it's closest outer edge (we're about 25000 light years from both). In other words, while we think of light speed as being incredibly fast, on the scale of the universe it's unfathomably, incredibly, absolutely SLOW.

  9. It would be interesting to ride a "string Theory" wave at c 10^32. We could travel 14.5 light years in 4.4 femto seconds.(pat Pending}..

  10. This video is nothing about how to travel faster than light lol as the title puts it. Should be which things CAN travel faster than light!!

  11. If two particles are entangled, and we don't know the spin of one until we look at it, the other particle didn't suddenly change, it's just that we didn't know what the spin was. The state didn't change faster than the speed of light, the spin was determined at the time of entanglement. We just didn't discover it until we looked at one. There is actually nothing spooky about this. If you have a bag with one red ball and one bag with one blue ball, you separate them by some enormous distance and you find that one bag has a blue ball, there is no signal travelling across the universe to the other bag, it contained the red ball at the time the balls were put in the bag, at the time of "entanglement".

  12. Would not a photon emitted by a galaxy moving away from us faster than c move toward us at c, red-shifted?
    Has anyone calculated that red shift? (Don't ask me to calculate it; I'm not smart enough.)

  13. In order to travel faster than the speed of light you would have to enhance your speed with an object.

    Maybe instantaneously make an object’s speed equal to a plot in space?

    My speed is spot A because I am at A. Now my speed is B because I’m instantly equal to space at plot B with no change in time.

  14. Well I'm sorry I refuse to believe that you can't go faster than speed of light cuz if you say a car is running 70 miles and its weight is 7000 lb it's still going to weigh 7, 000 pounds at 80 miles an hour

  15. I believe light travels in a wave up and down different frequencies bigger and smaller waves but they're not going the speed of light . Bigger waves would be slower and smaller waves would be going faster because the waves would be traveling a shorter distance. What you are observing is not the speed of light but the speed of time and can be sped up or slowed down. Time is relative to the we'll may be I'm wrong it's only a thought what do you think about this

  16. Information does not travel faster than c in regards of quantum entanglement.
    You need some knowledge about the other entangled particle before you have information being transferred. And that information has to be transferred at lightspeed or less.

  17. is the expansion of space the same in all directions? If so what drives it? The mass of the universe is not constant. I cant foresee dark matter or even dark energy being a constant throughout. It's almost as if there are extra dimensions unraveling and expanding our space time.

  18. Speed of light,..blah, blah blah. Meanwhile the speed of dark is infinite and can't be measured. Everyone talks about speed of light when it's actually dark travel that is going to get us to earth like exoplanets.

  19. This was awesome! Though i do think that an answer to such big questions must accomodate other "realities" such as mathematics, biology, chemistry, genetics, ph. classic & cuantic etc.. The impossibility of finding a valid answer comes from the fact that we cannot make all these work together whenever we come up with theories.

  20. There is no way to travel faster than light according to Einstein. I, once read however that so called UFO's move thru time in space rather than physically move thru space. This means that instead of say that UFO wanting to travel from earth to a nearby star rather than gain speed to reach that destination quickly it simply pushes itself thru time to that destination. Kind of like moving forward skipping the other three known dimensions like up, down and sideways and just moving to the destination. Hard for me to explain completely but it makes sense.

  21. I have to admit, I don’t completely understand why we can’t use entanglement to, say, have Internet connections across the Universe with near zero latency. (You still would have some latency on either side since computers aren’t infinitely small, I believe. And c still exists in a computer.). Is it because you can’t control the spin of one of the particles? I’m certainly no physicist but that’s the only explanation I can think of, offhand.

  22. The only thing supporting the 3rd proof is math and ignorance. x is distance, y is speed. So x distance away = y speed, 2x=2y, 3x=3y. This does not prove that there isn't a limit to the speed that can be achieved. It just proves that we don't know what the limit is, and, more than likely no galaxy is moving faster than the speed of light.

  23. If there was a planet 14 billion light years away looking at us, would they think we were moving away at the speed of light?? Or would they know they were moving away from us at the speed of light?? Or is it the same difference and doesn’t matter??

  24. Wrong the dark part of space is eternal and forever and has always been here.But all stars and galaxies have a beginning Scientists say 14 billion years.The bible says around 7000 years.The bible is the correct time becuase their has been time changes in the universe.The tick of the clock has changed in the star universe with had a beginning but the forever universe where God dwells in the 3 heaven .There you can see this universe as a tiny star.Its that far away.Some people have died and been there but where sent back becuase they were not ready.The soul is the only energy that can travel faster then light.


  26. Fermilab… An honest question: If at 28 billion light years distant, the universe is expanding at 2x the speed of light, does that mean a hypothetical craft traveling at the speed of light towards us could never arrive? I understand that it would be traveling relative to it's local area of space, but that space is… further apart…? And expanding twice as fast as the craft is traveling…? Now I have a headache 😉

  27. So how much time passes for a person moving at the speed of light 14bn light years (from the moving persons point off view)?

  28. after 04;28 mins got fed up – no practicle methods . As nobody has travelled anywhere near 'c' – devised experiments – e'mailed Proffessor michell doughty at imperial and provost micheal arther – much too busy to reply – and the (detail) say what ? Even how electric current behave at / near / beyound 'c' has to be studied as brain waves all electgric
    fergal sharky – electric dreams

  29. What if Light sits static in its birth place but the space around it expanding so it appears that light travels. What if no light travels to earth but the space expanded to earth taking the light born in it.

  30. what are the possibilities of approaching the speed of light very closely (to enjoy time dilation effects) and not having to have multi generation ships to reach nearby stars?

  31. What about a particle inside the schwarschild-radius of a black hole? Isn't the whole deal with a black hole that inside the radius the gravitational force is so great that the inwards acceleration makes the speed of anything with any mass exceed the speed of light, thus not letting anything escape even if that thing is traveling away from the singularity at the speed of light?

    Perhaps it is a matter of it not being possible due to the curvature to be traveling on a trajectory away from the singularity, rather than inward speed exceeding the speed of light.

  32. Even if we get to th this to travel with speed of light…. We will not be able to move away from small or big objects and they will hit the ship… And with that speed the slower object will hit a ship like a freaking planet ( comet, metoer etc ), small objects few inches big will pass trough the ship like he wasnt there……. That is physics too and you cnow it.. Best way for fast travel is to find how to open time wormholes that will bend the space and whatever thay do… I think all scientists should go in this way and research it instead of speed of light engines….

  33. So gravity is a force but if you measured it's force on a scale of speed is it faster than light , and ….. isn't dark matter faster than the speed of light, I thought dark matter is what's expanding space or is actual space itself

  34. Dude, I don't know what are your qualifications, but information in quantum entanglement exeriments DOES NOT travel faster than light.

  35. Light always and can only travel at the speed of c. It cannot slow down only be absorbed and emitted by atoms which delays light.

  36. I think maybe the point is that you can expand the fabric or space faster than light, but you are still stuck to it, so it doesn't help you, and this only is true of the entire universe. It is not a travel solution of any sort…

  37. To travel faster than light, we need to have absolute zero velocity. I feel this strongly inside, and I also believe that Einstein has postulated that we are looking in the wrong direction. Of course this has it's host of problems. Imagine we learned to stop, to absolute zero velocity. The universe moves away from us in orders of magnitude of c. One thing is for sure, we will never get back or control where we are going. At least not while standing still. Great idea for a probe.

    However, this is realistically possible. No law of physics says that we can't slow down.

  38. Okay, this should blow your minds. The distance at which space is expanding at the speed of light is just a little under 14 billion light years which means it takes light just under 14 billion years to reach us and that is the age of the universe as currently calculated. Think about that.

  39. For exploration purposes, it could be more advantageous to travel near the speed of light, utilizing time dilation to travel to the edges of the universe in a lifetime.

  40. Method 4: Be married for 20 years. My wife knows what I'm going to do before I do. I can only explain it using super-luminal telepathy theory.

  41. The phase speed of electromagnetic wave may also travel faster than speed of light. However, it doesn't bring any information.

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