Thread: Time travel loop

Time travel may not be possible, but it actually is plausible to look back into the past.

To explain how, consider this: it takes 8 minutes for light to travel from the Sun to Earth. That means, when you look at the Sun, you aren't seeing it in present time, you see how the Sun was 8 minutes ago.

Therefore, if someone was at the Sun (or equivalent distance) and had a way to look down at Earth, they'd see it, 8 minutes previous.

So theoretically, we could build a space station with an extremely powerful scope on it. Placing it 12 951 034 185 km away from earth (the distance light will travel in 12 hours) and have it relay what it observes back to earth at the speed of light.

Then, operators on Earth could use it to look at anything that happened the day before. Because it takes so long for the light and information to travel, they could watch exactly what happened 24 hours previous to the current time on Earth.

If you're interested, I'd recommend watching Brian Cox's video: "What Time Is It?" You can find it in parts on Youtube.

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I didnt realize there already was one on here, my bad.

Originally Posted by Vampyre

Time travel may not be possible, but it actually is plausible to look back into the past.

To explain how, consider this: it takes 8 minutes for light to travel from the Sun to Earth. That means, when you look at the Sun, you aren't seeing it in present time, you see how the Sun was 8 minutes ago.

Therefore, if someone was at the Sun (or equivalent distance) and had a way to look down at Earth, they'd see it, 8 minutes previous.

So theoretically, we could build a space station with an extremely powerful scope on it. Placing it 12 951 034 185 km away from earth (the distance light will travel in 12 hours) and have it relay what it observes back to earth at the speed of light.

Then, operators on Earth could use it to look at anything that happened the day before. Because it takes so long for the light and information to travel, they could watch exactly what happened 24 hours previous to the current time on Earth.

If you're interested, I'd recommend watching Brian Cox's video: "What Time Is It?" You can find it in parts on Youtube.

Not to put a damper on things, but... so?

We can already look into the past via video recorders, etc.

If we had a telescope far out in space it would be useless for looking into the past, because for every event we asked to see, the light from Earth would already have passed the telescope before the request signal from Earth.

Originally Posted by Xei

Not to put a damper on things, but... so?

We can already look into the past via video recorders, etc.

If we had a telescope far out in space it would be useless for looking into the past, because for every event we asked to see, the light from Earth would already have passed the telescope before the request signal from Earth.

The idea would be to create something similar to what you see in the movie Deja Vu. I'm aware that it'd take too long for the signal to get to the station.
It's the theory that makes it interesting, not it's current practicality

It's completely impossible unfortunately. It would violate special relativity if a signal from the past could somehow travel faster.

Don't think I've seen Deja Vu I'm afraid.

I do not believe paradoxes in time travel can occur.Say you've got a time machine and a chair. If you used a time machine to go back in time with the intention of destroying that chair when the chair was not destroyed in your reality, it simply wouldn't happen for some reason or other. Because if you destroyed that chair, it would have already been destroyed by you before you traveled back in time.

Unless each and every moment in time actually exists as it's own universe and every time you travel forward or back, you were actually traveling to another universe, alternate realities would not be a possibility. Creating an alternate reality would essentially be creating a whole other universe and all the matter that makes it up.

It's all in theory.
What if a time machine is invented that actually bends space and speeds you forward in time(Like moving really fast in the same spot.)
We're talking about going back in time, which I personally do not believe is possible or will be invented in the next several hundred years.
I think if you go back in time to before you found out you can time travel, you would see your future self and have a heart attack/go crazy/ kill them.

I have to add..

Time travel in the sense most people think about is.. impossible.. You know, the hollywood style.

You can't travel into the future because it hasn't happened yet! And neither can one travel into the past, though it is possible to travel into the past and future, but only as probabilities! Than means one can see the probable future, but not any actualized, in the same way one can visit the past as either actualized or unactualized, in other words, what happened and what didn't happen.

In quick summary, reality is not deterministic but only probabilistic in the sense of future and unactualized past, this is naturally one of the derives from free will. With free will the future can only exist as probabilites, as anything can happen.

No, you can travel into the future via going very fast or by being in close proximity to a very strong gravitational field. It's not disputed; and it's been observed experimentally in many forms.

We're talking about going back in time, which I personally do not believe is possible or will be invented in the next several hundred years.

So you think that either it is possible or it isn't possible?

Okay thanks.

Travelling into the past is possible in general relativity, but there would need to be a wormhole present (where the fabric of space time loops back on itself), and it's not certain if these are actually physically possible.