Do you agree with the following statement on time travel?

Question

I came across the following statement regarding the possibilities of time travel (i will not name the user):

The only way we could travel to the past is faster than light travel, which the laws of physics say is impossible.

Do the laws of physics clearly indicate that its impossible? how?

P.S. remember that photons appear and disapear around the speed of light.

Answer 1

I disagree. Light is able to travel with no resistance in any medium. I understand gravity can bend light in extreme situations but how could someone obtain this speed of light without any resistance. What type of capsule or device could you use to move at this speed with zero resistance? Unless you somehow found a material that completely ignores all resistances to air and heat.

Answer 2

Relativistic physics state that the closer an object with mass comes to the speed of light, the more energy it takes to accelerate. This means that it would take an infinite amount of energy (i.e. it is impossible) to have an object with mass (e.g. a person) going the speed of light.

Answer 3

Traveling faster than light travels means that time seems to travel slower for the traveler but for everyone else, time carries on as normal. So it is possible for it to seem like the traveler has traveled forward into the future but not into the past. In short, I disagree with your statement :D

Answer 4

Well in theory, if you did travel faster than light than in effect time would reverse, due to infinite time dilation. However since it is impossible for any object with rest mass to even accelerate to the speed of light then it would never happen anyway. The reason for this is that you would need an infinite amount of energy to accelerate something to the speed of light, and more than infinite energy to exceed it. Seeing as you cannot get more than infinite that makes it impossible.

But lets assume you CAN travel faster than light (for the sake of argument) I am in a spaceship steadily accelerating faster and faster. The faster i go the more time dilates, meaning i am already traveling further into the future. When i reach the speed of light however, time will dilate to infinity, meaning i have essentially travelled an infinite amound forward in time. So logically, even if i could exceed the speed of light, because am i already an infinite amount of time forward then it would be impossible to travel back. Because anything taken away from infinite is still infinity. But infinity does not exist in nature which makes this impossible to imagine.

Another way to travel backward in time is to warp space-time back on itself into a time loop, in which you would be able to travel back in time.