Time travel and the expanding Universe

[Seraldo Babalu]

Aside from the well known paradoxes with time travel (Grandfather effect, etc.) there is another angle that has never really been discussed.

Consider the assumption that the universe is expanding. Physically, all objects in the universe are constantly in motion and expanding. Therefore, an object will never be in the same physical location at two different points in time. 365 days from now, at this same time, the Earth may have expanded a few feet outward in the Universe, so traveling 1 year into the future may land you somewhere in the Earth's crust. Moreover, traveling 1 year in the past may land you a few feet off of the surface of the Earth, because the Universe has not yet expanded to where you physically were when you initiated the time travel in the future.

For those folks who believe time travel may be possible at some point, this may be an important limiting factor. No matter what, Earth will never occupy the same place in the Universe at two different points in time. Traveling years in the past may cause you to appear somewhere in Earth's atmosphere, and traveling in the future may land you somewhere in Earth's crust.

 

[M3t4tr0n]

Hows it work with flat earth doe?

 

[Exi]

 

[Roca]

Aside from the well known paradoxes with time travel (Grandfather effect, etc.) there is another angle that has never really been discussed.

Consider the assumption that the universe is expanding. Physically, all objects in the universe are constantly in motion and expanding. Therefore, an object will never be in the same physical location at two different points in time. 365 days from now, at this same time, the Earth may have expanded a few feet outward in the Universe, so traveling 1 year into the future may land you somewhere in the Earth's crust. Moreover, traveling 1 year in the past may land you a few feet off of the surface of the Earth, because the Universe has not yet expanded to where you physically were when you initiated the time travel in the future.

For those folks who believe time travel may be possible at some point, this may be an important limiting factor. No matter what, Earth will never occupy the same place in the Universe at two different points in time. Traveling years in the past may cause you to appear somewhere in Earth's atmosphere, and traveling in the future may land you somewhere in Earth's crust.

We can ignore the expanding universe theory and simply consider the movement of the earth in either a relative or absolute sense. The earth spins, orbits and translates through the universe. It spins around an axis, which wobbles. It orbits the sun, and the solar system orbits the center of the galaxy. The galaxy is also translating through the universe, and probably orbiting something else.

If you consider the center of the Earth, it has probably never occupied the same x,y,z of space ever, nor will it ever again return to a point it had previously occupied. And if you consider a point on the surface of Earth, that shit is wobbling and spinning and zip dap booping all over the fucking place.

However, all this simply negates a theory of 'teleporter-like' time travel a la Star Trek style instantaneous transportation. You wouldn't be able to stand on the surface of the Earth and instantly travel back in time and be standing in the same spot, 50 years ago. But you could do so in space (in a space ship). If you were floating in space, near the Earth, and traveled back in time 50 years, you could then travel through space to the Earth and return to the surface.

This assumes that there was no asteroid occupying the space you transport to, or assumes that a few atoms of whatever space dust occupies that space isn't going to violate some sort of fundamental of the universe and rip the very fabric of space-time apart or cause a nuclear explosion or some shit.

And of course the further in time you travel the greater your displacement from the Earth will be once you transport.

 

[liljoe]

Aside from the well known paradoxes with time travel (Grandfather effect, etc.) there is another angle that has never really been discussed.

Consider the assumption that the universe is expanding. Physically, all objects in the universe are constantly in motion and expanding. Therefore, an object will never be in the same physical location at two different points in time. 365 days from now, at this same time, the Earth may have expanded a few feet outward in the Universe, so traveling 1 year into the future may land you somewhere in the Earth's crust. Moreover, traveling 1 year in the past may land you a few feet off of the surface of the Earth, because the Universe has not yet expanded to where you physically were when you initiated the time travel in the future.

For those folks who believe time travel may be possible at some point, this may be an important limiting factor. No matter what, Earth will never occupy the same place in the Universe at two different points in time. Traveling years in the past may cause you to appear somewhere in Earth's atmosphere, and traveling in the future may land you somewhere in Earth's crust.

You have the right idea, but the earth along with the solar system is moving millions and millions miles a year. You would have to calculate your landing spot.
Check out this insane video. Really impressive. Jump to 16:50.

 

[weed]

 

[Pittie Petey]

Crust?
The Earth isnt a pie you dumb shit

 

[Kiddo716]

I've always thought about this exact problem concerning time travel. you wouldn't be in the same spot as you started due to the movement of the earth through space. unless your time machine accounts for that, your pretty fucked.

 

[Roca]

I've always thought about this exact problem concerning time travel. you wouldn't be in the same spot as you started due to the movement of the earth through space. unless your time machine accounts for that, your pretty fucked.

See my post re: space ship travel.

 

[minute bull]

 

[Kiddo716]

See my post re: space ship travel.

yes, I read it. what's interesting, no one knows the rules to time travel, if it can be done in a manner similar to what we see in fiction. We know you can travel into the future (it's been done with high-speed jets experiments), but the time difference is very small and not that significant. if it's done with speed alone then maybe the displacement issue won't be an issue because you are already moving. if it's more of a teleportation type of event, then you'd have to design the machine so that it takes displacement into account, and maybe it destroys any matter in the area you appear to avoid any nasty surprises.

 

[Roca]

yes, I read it. what's interesting, no one knows the rules to time travel, if it can be done in a manner similar to what we see in fiction. We know you can travel into the future (it's been done with high-speed jets experiments), but the time difference is very small and not that significant. if it's done with speed alone then maybe the displacement issue won't be an issue because you are already moving. if it's more of a teleportation type of event, then you'd have to design the machine so that it takes displacement into account, and maybe it destroys any matter in the area you appear to avoid any nasty surprises.

Time dilation because of relativity isn't really the same as the classical interpretation of 'Time Travel', and also wouldn't allow us to travel backwards in time.

 

[minute bull]

Man it is early to be this high. Woooooo! Shit.

 

[jefferz]

Hows it work with flat earth doe?

To understand it, you have to take a massive blow to the head first.

 

[Kiddo716]

Time dilation because of relativity isn't really the same as the classical interpretation of 'Time Travel', and also wouldn't allow us to travel backwards in time.

I know all of this. But time dilation is the only practical application we have so far (which isn't that convenient)

 

[Brodels]

Good fucking question. Damn it. Hopefully Scyther or Goretauro can come solve this for us.

 

[Brodels]

Man it is early to be this high. Woooooo! Shit.

Never too early. I just got stoned to pack for going out of town this weekend.

 

[minute bull]

When I realized that the universe is expanding in time as well as space, I realize the more I live in the moment the farther out on the edge of the universe I am.

 

[ralphc1]

Aside from the well known paradoxes with time travel (Grandfather effect, etc.) there is another angle that has never really been discussed.

Consider the assumption that the universe is expanding. Physically, all objects in the universe are constantly in motion and expanding. Therefore, an object will never be in the same physical location at two different points in time. 365 days from now, at this same time, the Earth may have expanded a few feet outward in the Universe, so traveling 1 year into the future may land you somewhere in the Earth's crust. Moreover, traveling 1 year in the past may land you a few feet off of the surface of the Earth, because the Universe has not yet expanded to where you physically were when you initiated the time travel in the future.

For those folks who believe time travel may be possible at some point, this may be an important limiting factor. No matter what, Earth will never occupy the same place in the Universe at two different points in time. Traveling years in the past may cause you to appear somewhere in Earth's atmosphere, and traveling in the future may land you somewhere in Earth's crust.

I've often posed the same problem. Anything that can defy the laws of physics isn't likely to be restricted by gravity or conservation of momentum. Everything is moving in relation to everything else so figuring out where anything will be at another time is problematic.

Much of the fictional time travel also combines travel to another location. Something similar to the Stargate system would provide a definite target but it would require something to be set up in the past which requires going back in the past to do that. Just like somebody would have to travel the universe to install the Stargates. These are things that science fiction writers like to gloss over.

 

[DoomPatrol]

You have the right idea, but the earth along with the solar system is moving millions and millions miles a year. You would have to calculate your landing spot.
Check out this insane video. Really impressive. Jump to 16:50.

I love that video, and VSauce in general. I highly recommend people watch his channel for some amazing physics and math explanations. I wish there were more channels like his that I knew about.