# Observing an event in the past?

I'm writing a Sci Fi novel and I'm trying to come up with a (fairly) realistic or at least vaguely plausible mechanism for this person's ability to exist and function.

Hypothetically, would it be possible for a person to somehow observe an event in the past, like watching a scene from a movie.

• Not to time travel. Their physical body wouldn't have to travel to the past event. But they would need to be able to observe an event.
• Also not to interact or change the event, simply observe.
• Would only need to be able to look back an hour or two, even minutes in the past, not years etc... although I'm not sure if this would make any difference.
• Can be an innate "ability" but doesn't have to be.

I just need hypothetical explanation for how this could be possible, if at all, doesn't need to be in great detail, just an outline.

What I've read about as possible thoughts, but don't understand well enough are:

• Light Manipulation (would possible to manipulate the light in such a way as to observe past events?)
• Perhaps even something like Gravitational Lensing? Where the light of the event is bent/ reflected and this person is somehow able to perceive it?

Unfortunately whilst I'm an avid reader, I'm not a physicist by any stretch of the imagination, and I don't know what to look for in the more complicated literature.

Any input appreciated! TIA

This isn't exactly possible, because no signals we have sent out were this strong, but if a broadcast signal was sent out into space and was reflected back to us, given the right conditions, you would be able to see the signal once it returned and it would be from the past but you would see it in the now. Think a mirror, its not you in the exact second but you at from a few pico-seconds ago since the light (signal) takes time to travel from you to the mirror and the to your eyes. A couple of movies played with this idea about how the first television signal alien's would get would be of Hitler.

A solution to this problem suggested by Clarke and Baxter in their novel The Light of Other Days is wormholes. Basically spacetime is riddled with quantum wormholes on the Planck scale, and somehow (hand-waving intensifies) the device can find one to the right event and allow detection of light that allows reconstructing a video.

The nontrivial topology on the Planck scale is a real physics possibility, but if you have technology that can manipulate this then the further implications are pretty enormous (the novel brings up a few).

(Electrodynamics has a lot of odd aspects, such as the advanced and retarded waves that would be more relevant in a story about a future viewer device. Maybe there is some similar weirdness there that can be used as a motivation for the device in your story.)

Some physical theories are symmetric with respect to time. If you make a video of particles in motion, say, then the laws of physics can be used to describe how those particles move. The curious thing is that when we play the video in reverse, the very same laws can still be used to describe that reversed motion.

So this might be a little bit on the wild side, but let's imagine a person who has the ability to reverse the fundamental processes that occur in his brain at will. Such a person could perhaps see an event in the past without actually remembering it the traditional sense. There are a lot of issues with this idea from a scientific point of view, but it might pass the test of vague plausibility. You would definitely have to explain away the arrow of time, because a lot of people are vaguely familiar with that concept.

What I like about this mechanism is that it is very personal to the character in question and that the process of "time travel" is not instantaneous. I imagine a decent writer could use this to good effect. Good luck.

Well, one assertion is that, if there were aliens on a planet million light years away, and they somehow had a telescope that could reach Earth, they'd see dinosaurs etc walking about. I don't know if that helps at all.

(I personally think this is a painfully ludicrous theory, by the way).

• Dinosaurs were wiped out about 65 million years ago. And you'd need a ludicrously huge telescope to focus on something the size of a dinosaur even a few light-seconds away Mar 15, 2018 at 2:31