Thread: Possible Way to Witness the Past?

I read an article that stated that theoretically, we could "ride" the fabric of space like a wave, allowing us to travel extremely fast. It said that the highest speed achievable currently would be the equivalent of .7 the speed of light. It's believed that space expands faster than light, so, theoretically, we could travel faster than light. (you're not actually moving at the speed of light, you're using space to move, so you're not breaking any laws of physics) That got me thinking that if we used this form of travel, then looked back, we could see ourselves taking off. Or you could go farther and see, say the Revolutionary War. Or watch the beginning of Earth. The possibilities are endless, and would allow us to make ten-fold the amount of discoveries than in all of human history.

To watch 30years in the past, you need to teleport 30light years away in an instant and then watch for light from Earth to arrive on your telescope. But its not possible to teleport faster than light. So we can't see the past.

Indeed.

The simple fact is, whatever you try to do, if you can only travel slower than the speed of light, you will never overtake a photon, so you can never see a photon that left before you did.

The expansion of the universe means that distant galaxies, currently 14 billion light-years away, are receding from us faster than a photon released here, but are at rest in relation to all the photons local to them. (i.e. they measure all photons to be travelling at c in relation to themselves, just as we do here)

Well If we could manage to fold the space/time fabric and be able to pass through both ends using the so called worm hole then we could take a short cut to any point in the universe thus placing ourselves well ahead of any photons that left our sun and earth. Which would mean we could then see (With a decent pair of binoculars!) what our sun and earth had looked like millions and millions of years ago. Erm hypothetically speaking of course.

I do not understand your answer.
If some nice E.T. were kind enough to build a huge mirror and send us back the signal it still won't mean we "witness" the past anymore that by witnessing an old video tape.
Don't get me started ... to late : One shiny day, Cesar got outside to take a leak on a mountain top. Sure enough, the image of is *i*k is now traveling somewhere in half the milky-way

Seriously, being the original photon or copies, does not change anything, it won't BRING THE PAST BACK. No more/no less than your mirror show you your past self from another space time continuum.

There is another thread about new-age physics and multiverse non-sense, and I feel like it is one of them.

Let's try another debunk method. To bring the past back, you have to make room in the present to welcome it. If you believe in law of conservation there is no way to add past (or anything else) into the present (unless this point zero energy it the way Cesar's *i*k is trying to came back to haunt us

Use a telescope :-)

Originally Posted by Boing3000

Seriously, being the original photon or copies, does not change anything, it won't BRING THE PAST BACK.

No one is suggesting bringing the past back, just being able to see it.

As the only way of doing this involves travelling faster than light and then having an implausible powerful telescope, it might just be simpler and more practical to build a time machine.

NASA working on faster-than-light space travel, says warp drives are ‘plausible’ | ExtremeTechhis is an article that explains what I'm talking about. I didn't explain it as well as they did.

Fascinating idea. I was actually thinking that if we took two particles, entangled them, and used it to send information, then we could achieve faster than light communication. If we attached one of these to a camera, and placed it on another planet then we could see into the past.
i.e. We place a camera on Mars, and can view the world as it was 7 minutes into the past.

Ronald Mallett has apparently developed a theory in which his machine creates a loop in the spacetime continuum active from when the machine is switched on to when it is switched off. I am not aware of the technical information or the credibility of his claims but regardless a very interesting read.

Originally Posted by Strange

No one is suggesting bringing the past back, just being able to see it.

Yes and no, because it is the same thing.
Seeing the past scientifically means being in the same causality chain as a photon emitted X time ago.
I do that every day, by watching the sky or my mirror, I see stars in both (can I still afford a joke now and then?)

If you mean to breaking causality and cloning some photon IN (not from) the past, not influencing it in any ways (you are careful, you don't know what it may have done to your gran-gan-great ancestors), and popping it into your current causality frame (breaking every known conservation rules known to geek-kind), it is bringing the past back

You cannot see the past. Every photon that hits your cornea will be in the same causality frame that your brain, with the rest of the universe.
Also, your unicorn may be able to escape this kind of limitation

Originally Posted by Strange

As the only way of doing this involves travelling faster than light and then having an implausible powerful telescope, it might just be simpler and more practical to build a time machine.

Or to buy a camcorder, you'll spare some money and avoid a strong head-ache (ask Arthur Dent)

Any subtle hints that we are being watched by future beings? I'm having trouble believing that the distant future is happening while I am passing through my now. If there is no evidence for the present being observed then am I to assume that our timeline is the leading edge of time marching forward? IOW's , if you want to observe my past from 100+ years in the future then you haven't been born yet. I think we would have more luck finding a cave on Mars where some alien civilization has stashed a photographic record of Earth since its beginnings.

If you're looking for a device that can observe the past and record it for you then we already have one, it's called a camera.