If we can travel faster than....?

Question

the speed of light, would we be going back in time?

I don't know if this just sounds like a silly question, but seriously, if you are travelling faster than light.. what do people think will happen?

I know it isnt possible... but if it was... do you think we would be seeing "old" light and so therefore be seeing the past?

Answer 1

Technically, it is impossible, so there is no real answer to your question. Warp speed has no been invented yet.

Answer 2

For all the criticism you have received, I assure you that it's not a stupid question. Unfortunately, I don't completely understand the answer, but I know where you can look.

Look up 'wormhole' in Stephen Hawking's "A Brief History of Time". He discusses the theoretical implications of faster-than-light travel achieved by traveling through a wormhole.

And don't shy away from asking "what-if" questions, even if the "what" is impossible. After all, asking that very question is part of what led Einstein to formulate the theory of relativity in the first place. So these mental exercises can be quite useful.

Answer 3

The faster you are travelling, the slower time applies to you. So for example, if you are travelling 1000s of miles per hour in a space ship for a few days, then return to Earth, you will technically be less aged than your identical twin.

As you approach the speed of light, time slows down to zero, and your mass approaches infinity. The reason you cannot exceed the speed of light (as far as scientists are concerned) is because it would require an infinite amount of force to accelerate you past the speed of light. At the speed of light, time for you would be at a standstill. If you were to go past it, then I have no clue what would happen. But I'm assuming it'd be pretty awesome.

Answer 4

it is not theoretically possible to travel faster than light because it violates the special theory of relativity. As particles or matter approach the speed of light mass increases requiring more energy to further increase speed. calculations indicate that it would take all the energy of the universe to even accelerate electrons to the speed of light. currently electrons can be given near light speed or .99c but never beyond it. If you can travel at near light speed then time slows a lot for you meaning you might be able to build a time machine that goes to the future based on this principle but as far as going back in time it is very difficult but there are theories such as worm holes and cosmic strings that can be manipulated that may allow you to travel to the past from the present but then you run into problems of causality and paradoxes. But the point is it is impossible to travel to the past by going real fast. you can go to the future but not the past.

Answer 5

Your question is a very interesting one, and it is great to see that you are thinking about Professor Einstein's theory in this way, but unfortunately, you're probably not going to like the response. When you assume that it's possible to travel faster than the speed of light, you're taking the laws of physics and punching them in the stomach and throwing them down the stairs.

The problem is that you can't say, 'Hey, what would happen if you could go faster than the speed of light?' because that's totally physically impossible. It's not possible to go faster than the speed of light, so the laws of physics can't possibly say what would happen if you imagine things that way in some hypothetical universe. Physics is a complete package: once you decide to ignore one physical law, you're ignoring them all.

You run into a similar problem when you ask 'What if I could divide by zero?' or 'What if I could build a perpetual motion machine?' or 'What if I went back in time and killed my grandfather before I was born?' There's no answer, because the question doesn't make any sense.

Of course, this doesn't bother the writers of Star Trek. They go faster than the speed of light every show and travel into the past like it's a trip to Disneyland. This brings up an interesting point, however: The idea of a space-warping engine is NOT entirely a bad one! Warping space would allow you to travel as if you were moving faster than light by changing the structure of the universe, at least temporarily. You would end up in a certain location much faster than if you travelled there the 'normal way,' kind of like a secret passage. Happily for relativity, you would STILL not actually be travelling faster than the speed of light in local space, so Einstein's 'speed limit' still holds.

The point is that though it's fun to think about and enjoy in science fiction, truly going faster than the speed of light is a violation of the laws of physics and therefore can not really be discussed by physics. I can't say time would reverse itself or not exist or anything because those aren't even options. It's like if I invited you out to dinner and you told me you absolutely couldn't come, but then I asked you whether you were going to have the soup or the salad!
One of the reasons that prevent any object with a mass going at or faster than the speed of light is that the mass is not constant - it increases with velocity and it goes to infinity at the speed of light. So that eventually you need infinite amounts of energy to accelerate infinite mass past the speed of light mark! (and as far as I know we have yet to find an infinite source of energy

Answer 6

A far deeper question than I can answer,but dont stop asking it.
There are some very good replies explaining why you cannot get to the speed of light, some of the answerers wise enough to use the word THEORETICALLY others blindly using the phrase LAWS OF PHYSICS. Just try to remember these "laws" are not natural they are created by us to help explain what we know so far. They have an annoying habit of changing when we know better. The possibilities of us being able to travel without the "mass" of our bodies is a potential route around many obstacles. To fully explore the potentials you require a better mind than mine (plenty of people can quote so called laws of physics there are probably only a handful in the world who can understand the theories (at present) well enough to explain them simply) So keep on asking.

Answer 7

The laws of physics were derived from what we know, they merely formally explain how the physical world behaves in a given situation. The mathematics involved is abstract, many of the variables involved are on-observable. The answer to your question may lie in the possibility of not travelling faster than light but being able to "bend" space in order to make travel quicker. By bending space there can be no problems arising from time travel, time is measured from a fixed point and never varies from one point in space to another. 3.10pm on Earth occurs at the same time as 3.10pm on Mars, if we can bend space we can arrive on Mars at 3.10pm without travelling faster than light.

Answer 8

There is a hypothetical class of sub atomic particles called tachyons that - if they exist - would travel faster than the speed of light. However, as the light speed barrier cannot be crossed (you reach infinite mass), they would have ALWAYS been travelling faster than light.

And yes, these particles would travel backwards in time. They would also have the rather perverse property that if you increased their energy they would slow down.

Answer 9

If you consider the photon clock as the basis for time dialation rather than a consequence thereof, then traveling back in time would not be a logical consequence of faster than light speed travel.

Answer 10

The first problem to overcome is you cannot accelerate at a safe enough rate in your lifetime to achieve that speed. To try otherwise would crush your body. If , however, you could cyro-freeze yourself for 600 years or so, you could then safely achieve speed of light. Then thaw and proceed!

Answer 11

Hi,

Not only back in time, but forward also.
Traveling through time would'nt alter your appearance,
but others would have aged. As weird as it sounds,
that what scientist say would occur.