B Can We Use Space/Time Fabric to See the Past?

[mgsullivan24]

TL;DR Summary

Is the space/time fabric analogy portrayed in movies and on YouTube consistent with actual physics and if so…

Common these days is explaining worm holes and the space and time correlation as a fabric which could allow for the fabric to be manipulated in a way that would allow for time travel. The way I’ve understood the concept is that you could fold the fabric to touch two different areas together and move between them which could allow you to revisit earth at a different place in time. Is that actually consistent with real physics?

If so, why don't we see earth and other objects in the places they were at during that time? Why can’t we look back to where earth was a year ago and see it existing at that moment in time?

Im sure I'm not even asking the question correctly but can anyone help me out here?

 

[PeterDonis]

Is the space/time fabric analogy portrayed in movies and on YouTube consistent with actual physics

It's not precise enough to be either consistent or inconsistent with actual physics. It's just an analogy and doesn't really help you to make predictions.

why don't we see earth and other objects in the places they were at during that time?

Um, because there aren't any wormholes near Earth?

 

[mgsullivan24]

It's not precise enough to be either consistent or inconsistent with actual physics. It's just an analogy and doesn't really help you to make predictions.


Um, because there aren't any wormholes near Earth?

A wormhole would be required to see only 1 year back? Ok what about a month? At some point isn’t a telescope essentially acting as a “wormhole”?
I guess I’m way way off on my very limited understanding of space and time.

 

[PeterDonis]

A wormhole would be required to see only 1 year back?

A wormhole is what you were asking about.

At some point isn’t a telescope essentially acting as a “wormhole”?

You can't look at Earth with a telescope that's on Earth. With a telescope on Earth you can see distant objects as they were one light travel time ago; for example, you can see objects one light year away as they were one year ago. You can't change that; you can't adjust your telescope to see, say, Alpha Centauri as it was 2 years ago, or 6 years ago for that matter, instead of 4.3 years ago.

 

[Ibix]

A wormhole would be required to see only 1 year back? Ok what about a month? At some point isn’t a telescope essentially acting as a “wormhole”?
I guess I’m way way off on my very limited understanding of space and time.

You always see things as they were in the past because of the finite speed of light. Even if you look at yourself in the bathroom mirror your reflection is how you were a couple of nanoseconds ago, although on that timescale it's unnoticeable to humans. But this doesn't really have much to do with models of spacetime, it's a fact of life if you don't have some form of radiation that moves at infinite speed. Your information is always out of date. This is how instruments like the James Webb telescope "see back in time" - they can just see things further away, so they see light that was emitted a long time ago. You could only see our galaxy as it was a million years ago if someone had helpfully built a giant mirror half a million light years away half a million years ago.

Wormholes can, possibly, permit time travel in the "go back and shake hands with your younger self" sense. But such solutions to the equations tend to require something impossible like negative mass matter, so they're probably just a mathematical curiosity.

 

[Vanadium 50]

What is different about space? Why can't I use binoculars to look at the hawk that was in my backyard yesterday?