Looking back in time

[Himster]

Ok, this is a little bit crazy. What if we had a mirror in space? We would see our reflection, but delayed, right? How about we move that mirror a few light-years away, in a few years time we'd be able to see our reflection but a few years ago, literally looking back in time.

Does that make any sense, or have I been up for too long?

[MathiasOfAthens]

No thats not possible. Thats like holding up a mirror in front of a car so you can see whats behind you.

[Himster]

No thats not possible. Thats like holding up a mirror in front of a car so you can see whats behind you.

And if the mirror was so far away you're looking at yourself from years ago, doesn't that make sense?

[MathiasOfAthens]

No Im sorry Its not possible mate. The image would just be smaller.

[Himster]

No Im sorry Its not possible mate. The image would just be smaller.

Yes it would be smaller. But when would the image be of?

[Aetius]

Theoretically its possible, its the same concept we use to see stars. All stars you see are ancient images of themselves. The sun you see is 8 minutes in the past.

Earth's light reflects of the earth into space, we never see it again.

BUT if we had a mirror it could be reflected back at us at a much later date thus seeing into the past

If we had a mirror out 1000 Light years and we could somehow mitigate the dust we could theoretically see the Roman Empire, and the ancient world of Earth.

[MathiasOfAthens]

Theoretically its possible, its the same concept we use to see stars. All stars you see are ancient images of themselves. The sun you see is 8 minutes in the past.

Earth's light reflects of the earth into space, we never see it again.

BUT if we had a mirror it could be reflected back at us at a much later date thus seeing into the past

If we had a mirror out 1000 Light years and we could somehow mitigate the dust we could theoretically see the Roman Empire, and the ancient world of Earth.

Yeah if you could somehow travel faster than light. But if it took you 1000 years to get that mirror out there than prob not.

[Boer]

Yeah if you could somehow travel faster than light. But if it took you 1000 years to get that mirror out there than prob not.

I think he is saying that it would already be there and be large enough that we could see it from earth. Therefore, the light would travel from us to the mirror, then back, taking 1000s of years, and by standing here looking at the light returning from the mirror we could see back in time.

How/when it got there and who managed such a feat seem irrelevant to this hypothetical, just that there already is a mirror and, therefore, its showing us the past.

[Himster]

What we need is a stargate..............but then we'd have to wait for the light to get there and then get back.

But most interestingly I wasn't wearing pants when I thought of that, a real break through.

[empr guy]

Ok, this is a little bit crazy. What if we had a mirror in space? We would see our reflection, but delayed, right? How about we move that mirror a few light-years away, in a few years time we'd be able to see our reflection but a few years ago, literally looking back in time.

Does that make any sense, or have I been up for too long?

well, the dust would distort the image, and the atmosphere, and it would probably be broken by a rock travling throught space, etc etc etc, but if you could deal with or you count out those factors then there is no reason why that shouldnt work.

Yeah if you could somehow travel faster than light. But if it took you 1000 years to get that mirror out there than prob not.

huh? the way i understand it, he means if we had a mirror a few light years away that we discover tommarow but has been there long enough for the light to get their and bounce back, and we can clearly see the image, when would we see it? the answer would be we can see it depending on how many light years away it is.

[Elfdude]

Yes. It takes a certain amount of time for even light to travel a distance. However putting a mirror lightyears away would be ineffective. If we put a mirror 50 light-years away it would take us 50 years to see it. We could see what the earth looked like 100 years before. This is assuming we somehow have a perfect mirror that is capable of giving us the visual clarity at 100 light years of distance that could still see any real or useful detail.

However if you instead think of faster than light travel, if you were to hyperjump (whatever you want to call it) 50 light years away almost instantaneously the light reaching you at that point would've already have been traveling from the earth for 50 years. You could then observe in real time exactly what history held for us assuming perfect visual conditions.

It's the visual conditions part that makes it difficult. It's very hard to get enough light to reconstruct a picture at that distance, something we're only barely getting to the point where we can see shadows of planets much less any detail. It's unclear whether it's even possible that at that distance the light would still be plentiful enough for you to reconstruct a picture at all. This is assuming gravity distortions don't throw the light far far away, that nothing stops the light and that there isn't too much light pollution from other light sources.

However if we are just talking about cosmology, it would be very valuable to be able to have different observatories at different distances observing how history unfolded giving us points to plot on the timeline that we know concretely occurred which would allow us to more accurately describe the evolution of the universe over time.

[Himster]

Maybe if we changed the idea to massive high speed cameras that transmit the data. That way we could have several of them at various distances so if we want a specific date to look at we can just bring up the camera in the right position.

[Tacitursa]

It would work but you wouldnt see much. Everytime you look at the sky your looking at the past but not in much detail even if you zoom in with telescope.

But by the time we have the technology to travel those distances or hyperjump we will no doublt be able to manipulate gravity and time travel could even be possible. There's a theory that blackholes can allow you to travel to the past/future if you enter it's orbit where spacetime is distorted do a few laps and then exit again you'll be in a different time period. It could also be possible to create a wormhole that connects to a different time.

Would be pretty awesome to have all of histories major battles captured live on DVD. Who's know perhaps the UFO's people claim to see are just us from the future recording certain parts of our history

[Gordon Freynman]

Would be pretty awesome to have all of histories major battles captured live on DVD. Who's know perhaps the UFO's people claim to see are just us from the future recording certain parts of our history

You think they'll have DVDs that far in the future?

[Tacitursa]

lol good point

[Elfdude]

Maybe if we changed the idea to massive high speed cameras that transmit the data. That way we could have several of them at various distances so if we want a specific date to look at we can just bring up the camera in the right position.

The issue is that nothing travels faster than light not even data. Until we have faster than light travel any such system would be utterly pointless and trivial, we couldn't place it far enough fast enough to see before the mirror was even in existence. Yes it would be of some use in a couple hundred years for anyone who wanted to see what it was like (assuming it survived without any decay/tarnish/dust) but it wouldn't be any use any time soon and by the time it was it might be an utterly pointless thing made obsolete long before. If we were to find such a system already existing in space we could utilize it assuming we had the clarity but even that's assuming a bit much.

[Himster]

The issue is that nothing travels faster than light not even data. Until we have faster than light travel any such system would be utterly pointless and trivial, we couldn't place it far enough fast enough to see before the mirror was even in existence. Yes it would be of some use in a couple hundred years for anyone who wanted to see what it was like (assuming it survived without any decay/tarnish/dust) but it wouldn't be any use any time soon and by the time it was it might be an utterly pointless thing made obsolete long before. If we were to find such a system already existing in space we could utilize it assuming we had the clarity but even that's assuming a bit much.

What if we find a super shiny planet that's like a thousand light years away, maybe we could see ourselves from two thousand years ago, that'd be undeniably cool.

[Elfdude]

What if we find a super shiny planet that's like a thousand light years away, maybe we could see ourselves from two thousand years ago, that'd be undeniably cool.

Well yes. However I'm not sure if the concentration of photons and reflection is high enough to generate an image at all. At those distances. Also I lied, data can be transfered instantly via entangled particles as far as I know but as far I as know that technology is only experimental.

[Himster]

Well yes. However I'm not sure if the concentration of photons and reflection is high enough to generate an image at all. At those distances. Also I lied, data can be transfered instantly via entangled particles as far as I know but as far I as know that technology is only experimental.

The negative vibes make me a sad panda.
Couldn't you lie and say: hey great idea Himster or you're a genius Himster or make love to me Himster, or something nice like that.

[Elfdude]

That's not a fair characterization of pot

I'm high most of the time I'm on this forum.