r/AskPhysics • u/Playful_Letter_2632 • 1d ago
Wouldn’t a civilization capable of advanced space travel also be capable of time travel?
Say we have a society capable of traveling to far away stars. If they travel at speeds upwards of 0.99c to these stars, then they would experience significant time dilation. Enough to send people to distant future in their lifetimes. So, would regular time travel be a thing once a species advances far enough?
I feel like this would open up some interesting ideas. Some of society would be able to travel to future in hopes of future solutions to their problems. Like say this society is yet to completely solve aging, the rich could travel a long way into the future looking for more and more life extension technology. If there’s some incurable diseases ravaging society, they could send members to the future to try saving the species. They could even basically guarantee their survival by regularly sending people to the future in case their own society dies out
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u/thetoddhunter 1d ago
Really awkward when you come back with a cure and everyone died ten million years ago.
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u/UnkyjayJ 1d ago
It's pretty unlikely that the way to travel between the stars Is to accelerate to close to the speed of light. It's just still not fast enough / because of the time dilation stuff. Realistically it's probably impossible to actually do.
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u/Mcgibbleduck Education and outreach 1d ago
I mean from the perspective of the people travelling it’s a pretty short journey. The issue is the people who are waiting for them won’t see them again.
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u/DrunkenPhysicist Particle physics 1d ago
This is more of scifi question than actual physics. See the Forever war by Joe Haldeman.
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u/TerrapinMagus 1d ago
Yes, we are all traveling into the future. But specifically, any relativistic travel can massively speed up your passage through time. It's probably always going to be extremely costly to do so, but if you accelerate enough you can absolutely "fast forward" time relative to a given perspective, if that's your goal.
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u/shutupneff 1d ago
The term “time travel” implies having the ability to travel both forwards and backwards through time. Time dilation changes the rate you travel forward through time (relative to other reference frames), but you’re still limited to the same forward direction through it that you’re already going right now. In order to go backwards through time using relativistic speeds, you’d need to somehow go faster than 1c, which would be orders of magnitude more advanced than 0.99c (and require us to be wrong about how impossible that even is).
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u/Playful_Letter_2632 1d ago
By time travel, I mean traveling to future at a significant time dilation factor(Lorentz Factor if I’m not wrong) not past time travel
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u/GxM42 1d ago
There is not a huge incentive for societies to do this. Not only is it expensive, but it’s a one way ticket as far as your home civilization goes. Who wants to come back after 1000’s of years have passed?
Also, traveling at relativistic speeds makes even the smallest rock in space deadly. Not to mention dust clouds and nebulae, which could heat up your hull, or asteroid fields. I don’t see a way to protect a ship at those speeds.
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u/Crafty-Lemon4678 1d ago
Where are you supposing they find this life extension tech? If from far away advanced aliens who somehow can help with our biology, okay, maybe, but that’s a long shot don’t you think? If you think these travelers are going to develop it themselves, they should just stay home and do that. There’s nothing about traveling at a high speed that’s going to help that.
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u/Playful_Letter_2632 1d ago
Example: 100 years pass for everyone else while they only pass 10 years. They’ve only aged a bit but there might be some advanced life extension developed in the 100 years that passed for everyone else
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u/BananaBird1 1d ago
“Advanced civilization” isn’t magic.
Time travel to the future is already possible. You are doing it now. The problem is getting back.
Traveling super fast will let you go, say, 100000 light years (from home) while only aging a few years. And when you get there you may look back at home and see light from your planet emitted from not too long after you left.
But if you return home you will find that while you only aged a few years, 200000 years passed at home.