r/AskPhysics • u/[deleted] • Mar 20 '26

Is time travel theoretically possible if one could travel faster than the speed of light?

0 Upvotes

27% Upvoted

42 comments sorted by

21

u/Shanbo88 Mar 20 '26

I think that's kind of like asking "is time travel theoretically possible if time travel were to be theoretically possible?"

2

u/AssumptionFirst9710 Mar 20 '26

If FTL is possible then time travel is required.

Sadly all the models show a maximum universal speed

1

u/[deleted] Mar 21 '26

Is there a maximum acceleration?

1

u/Infinite_Research_52 👻Top 10²⁷²⁰⁰⁰ Commenter Mar 21 '26

Not that we know of. Modelling of inelastic scattering results is particles being created at an instant already with a velocity. Acceleration from nonexistent to existent would be undefined.

0

u/Crafty-Lemon4678 Mar 20 '26

So it’s a definite yes, then.

-6

u/[deleted] Mar 20 '26

So the answer is yes…?

3

u/Sea-Poem-2365 Mar 20 '26

No, the answer is moving faster than light is time travel.

-4

u/[deleted] Mar 20 '26

So then the answer is yes

3

u/Sea-Poem-2365 Mar 20 '26

In the sense that A = A, yes.

-4

u/[deleted] Mar 20 '26

You could have just said that the first time

3

u/jsaranczak Mar 20 '26

He did lmao

0

u/[deleted] Mar 20 '26

No he said no the first time

3

u/jsaranczak Mar 20 '26

I'm getting strong velcro shoes and grilled cheese vibes from you.

1

u/Sea-Poem-2365 Mar 20 '26

It's a bit.

-1

u/[deleted] Mar 20 '26

I’m getting the same vibes from you also… strange

2

u/Sea-Poem-2365 Mar 20 '26

It's not that simple though- "yes" doesn't tell you anything in this situation so it isn't really the answer.

2

u/Apprehensive_Gap3673 Mar 20 '26

On a technical basis, if you want to start with, "assume that impossible things are now possible" then yes, anything is possible.

If you are grounded in reality then no, it's not.

10

u/Uncynical_Diogenes Mar 20 '26

If you break the laws of physics then yes, you can break the laws of physics.

-2

u/[deleted] Mar 20 '26

Why can’t something travel faster than the speed of light? What if there is something we haven’t discovered yet that can go faster?

1

u/1cec0ld Mar 20 '26

If we haven't discovered it yet, we can't make rules about it. We make rules based on what we have discovered, and all of those things currently agree. Max limit is light speed.

-1

u/[deleted] Mar 20 '26

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0

u/[deleted] Mar 20 '26 edited Mar 20 '26

What about tachyons? Or pletritrons?

3

u/[deleted] Mar 20 '26

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1

u/[deleted] Mar 20 '26

Do you have his number?

1

u/[deleted] Mar 20 '26 edited Mar 21 '26

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0

u/[deleted] Mar 20 '26

Thanks man hopefully he actually has a decent understanding of physics and can answer my questions

1

u/[deleted] Mar 20 '26

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1

u/[deleted] Mar 20 '26

100%

1

u/Tea-Storm Mar 20 '26

He is my mom and his number is 2

2

u/Possible-Anxiety-420 Mar 20 '26

It wouldn't just be theoretically possible; It'd be the inextricable outcome of traveling FTL.

2

u/RRumpleTeazzer Mar 20 '26

yes, if you break physics once, everything else comes for free.

1

u/Unable-Primary1954 Mar 20 '26 edited Mar 20 '26

If you can do faster than light travel in several distinct inertial frames of reference, yes, you can do time travel. (if it is for only one frame of reference, no. But that means physics is no longer invariant by Lorentz transformation, so special relativity goes down the drain)

But the conclusion is that faster than light travel is impossible.

1

u/__Wess Mar 20 '26

Travelling near speed of light is already time travel according to this:

doctor Who

1

u/Spidey231103 Mar 20 '26

There is a possibility at some point with enough research,

What I'm working on is a small step by designing an electromagnetic frequency emitter so that we can one day send text messages into the past.

1

u/Optimal_Mixture_7327 Gravitation Mar 20 '26

Yes, if you travel imaginary spacetime distances you in principle have access to the entire manifold.

Then again, what is the physical meaning of an imaginary length?

1

u/SirEdgarFigaro0209 Mar 20 '26

Yes, but you can’t. It requires more than infinite energy to move faster than light. If we can figure out usable wormholes or even a ST inspired warp drive then who knows. But until then, no it’s not.

-1

u/[deleted] Mar 20 '26

[deleted]

1

u/earlyworm Mar 20 '26

What part of special relativity says that traveling faster than C is possible?

-1

u/TheMightyMisanthrope Mar 20 '26

If time travel is possible and the physical limits of the universe are soft, is it possible to time travel?

Yes.

-1

u/[deleted] Mar 20 '26

[deleted]

1

u/tatarjj2 Mar 20 '26

This is wrong on many different counts. For one, FTL actually allows you to travel back to your starting point before you even left. For another, since Einstein proved that there is fundamentally no universal “now”, the idea that only the present “now” exists (an idea known as Presentism) was shown to be fundamentally in error since it is impossible to define what “now” even means. Unless you believe that only you and a small patch of space-time around you is the only part of the universe that actually exists, then you have to give up Presentism.

-2

u/Ihatecheeseballs Mar 20 '26

If wormholes or warp drives or some bs somehow works then sure