What If We Could See the Past by Placing a Mirror on the Sun?

[Colm Curley1]

TL;DR Summary

What if we could see the past, not just through history books, but in real-time? Imagine placing a mirror on the Sun, reflecting its light, and using a super-powerful microscope to observe Earth’s past. It sounds like a science fiction dream, but it’s a mind-bending thought experiment that could radically change how we understand time.

Light from the Sun takes about 8 minutes to reach Earth. So, theoretically, by positioning a giant mirror on the Sun, could we bounce this light back and peer in

What if we could see the past, not just through history books, but in real-time? Imagine placing a mirror on the Sun, reflecting its light, and using a super-powerful microscope to observe Earth’s past. It sounds like a science fiction dream, but it’s a mind-bending thought experiment that could radically change how we understand time.

Light from the Sun takes about 8 minutes to reach Earth. So, theoretically, by positioning a giant mirror on the Sun, could we bounce this light back and peer into Earth's past? Could we witness the extinction of the dinosaurs or watch the rise of human civilizations, as if we were traveling back in time? The idea challenges everything we know about physics and the nature of time itself.

Could this be the key to unlocking the mysteries of the past and future? Could powerful microscopes and telescopes capture this reflected light, allowing us to see history unfold in front of us? This is more than just a thought experiment—it's a wild, speculative journey into the boundaries of science, time, and space, where the impossible might become possible.

 

[berkeman]

Welcome to PF.

Light from the Sun takes about 8 minutes to reach Earth.

Your enthusiasm is good (I think), but if I want to look back in time 16 minutes, I'll just record on my GoPro and play it back.

allowing us to see history unfold in front of us?

Whatever mechanism you want to use to watch the past, it needs to have been in place at the time of the past you want to watch.

 

[FactChecker]

TL;DR Summary: What if we could see the past, not just through history books, but in real-time? Imagine placing a mirror on the Sun, reflecting its light, and using a super-powerful microscope to observe Earth’s past. It sounds like a science fiction dream, but it’s a mind-bending thought experiment that could radically change how we understand time.

It's just a more extreme version of looking at your reflection in the bathroom mirror. I don't think there is anything profound about it.

Light from the Sun takes about 8 minutes to reach Earth. So, theoretically, by positioning a giant mirror on the Sun, could we bounce this light back and peer in

We could position two mirrors bouncing light back and forth as many times as we want.

What if we could see the past, not just through history books, but in real-time? Imagine placing a mirror on the Sun, reflecting its light, and using a super-powerful microscope to observe Earth’s past. It sounds like a science fiction dream, but it’s a mind-bending thought experiment that could radically change how we understand time.

I don't think it changes our understanding of time.

 

[phyzguy]

Why stop at the sun? Put a mirror in orbit around Alpha Centauri and see eight years into the past.

 

[berkeman]

Why stop at the sun? Put a mirror in orbit around Alpha Centauri and see eight years into the past.

...starting 8 years after the mirror arrives on-station.

 

[bob012345]

This is more than just a thought experiment—it's a wild, speculative journey into the boundaries of science, time, and space, where the impossible might become possible.

Could you give an example of that?

 

[PeroK]

I can still, more or less, remember what happened 15 minutes ago!

 

[jbriggs444]

We could position two mirrors bouncing light back and forth as many times as we want.

There are some technical challenges lurking here.

If we are continuously streaming information into the gap between these mirrors, the amount of information bouncing back and forth will increase over time. We have to be concerned with capacity.

The mirrors will have to be exceptionally perfect. If we want to capture the 14 minutes of Michael Jackson's "Thriller" within a 10 meter mirror gap, the signal will have to be reflected 25 billion times. So the mirrors need to be something like 99.99999999% perfect. Same for the gap between the mirrors.

Then we need to worry about playback. We need to let the signal out and watch the recording. But that means watching signal from the first bounce. Then signal from the second bounce. And so on. We need to arrange for the signal to spill out over the course of 14 minutes. Maybe this is a pair of long parallel mirrors 10 meters apart and 100 meters long with each bounce of the signal beam some 4 nanometers to the left of the previous. So it seems that we have to worry about aiming and focus.

Thanks, but I think I'll just download the video. Yes. The voice of Vincent Price is just as I remembered it.

 

[Ibix]

Could we witness the extinction of the dinosaurs or watch the rise of human civilizations, as if we were traveling back in time?

No. The reason is simply that, as @berkeman pointed out, you can't see further back than when you emplaced the mirror (strictly, the actual even-in-principle limit is when you sent out the mission to emplace the mirror). Essentially, what you are describing is a form of optical delay line memory, not a time machine. @jbriggs444 made a start on the technical challenges, and there are others beyond what he wrote.

It's a non-starter, I'm afraid.

 

[FactChecker]

There are some technical challenges lurking here.

If we are continuously streaming information into the gap between these mirrors, the amount of information bouncing back and forth will increase over time. We have to be concerned with capacity.

The mirrors will have to be exceptionally perfect. If we want to capture the 14 minutes of Michael Jackson's "Thriller" within a 10 meter mirror gap, the signal will have to be reflected 25 billion times. So the mirrors need to be something like 99.99999999% perfect. Same for the gap between the mirrors.

Then we need to worry about playback. We need to let the signal out and watch the recording. But that means watching signal from the first bounce. Then signal from the second bounce. And so on. We need to arrange for the signal to spill out over the course of 14 minutes. Maybe this is a pair of long parallel mirrors 10 meters apart and 100 meters long with each bounce of the signal beam some 4 nanometers to the left of the previous. So it seems that we have to worry about aiming and focus.

Thanks, but I think I'll just download the video. Yes. The voice of Vincent Price is just as I remembered it.

Hmmm. Ok. Then I won't try it. ;-)

 

[phinds]

it’s a mind-bending thought experiment that could radically change how we understand time.

Uh ... no, it isn't, actually. Colm, it's admirable to think outside the box but first you need to understand what's IN the box.

 

[Baluncore]

You need to survive long enough to experience the future, and the yield on your educational investment. Look forwards, not backwards. Predicting the future is where the money is now.

Take plenty of pictures along the way, for your own protection. There is no advantage to be gained, by seeing the past with greater clarity. Let the lawyers and historians, argue over what happened in the past.

 

[jedishrfu]

It seems we have exhausted this topic, and now is an excellent time to close the thread.

Many thanks to all who contributed here.

Jedi