Dark Traveller
Striker
You're right that time is not this simplified linear stream that we all travel down and can take a measurement to see what the time is, but it does indeed exist and has a direction. It's part of the arrow of time, and shown with nucleonic decay and entropy which are at the heart of thermodynamics. Look at the half life of Uranium 232 for example, it has a half life that always decreases in one direction.. ie forward in time, not backwards and at a uniformly calculable rate. So essentially, time is a measure of entropy.
Here's some good video about Entropy form PBS Space Time :
As far as time travel (back) is concerned, QM says there's no reason at all why reverse time travel is not possible and QM likes to pat itself on the back by saying that it's observations are some of the most accurate in all of science.
In fact this duality is at the very core of modern science and are part of Feynman diagrams which are paths through time, both forward and back.
Again, the practicalities of doing with with a human who has mass makes things a lot, lot harder. But if you remember the red angel suit was covered in a quantum field.. which is a pseudoscience get-out-of-jail-card to fudge that it might means the suit is massless.. At that point it's all possible.
Putting all of this aside for one second, time travel into the past has already happened, many times.
If you take into account the observer effect and special relativity and that fast moving object have a different frame of reference and you'll know that things like ISS are actually receding in time compared to us in a very real way.
This is why GPS satellites have to have their internal clocks adjusted. Not because they are wrong, but because time flows at a different rate for them.
I know it sounds bonkers, but that is time travel into the past. However, it doesn't mean to say we can go back to 1900. It just means that future events can be ahead of other future events and due to relativity, one will see the other as moving into the past. Still travelling back in time, but in a different way. I think this is related to when it's said that you can't travel back in time before the time machine was invented.
I was brought up with classic science telling us time travel was not possible, ever, at all.. nada. but I've seen that argument being born from quite naive assumptions, like for example assuming your trying to shove a spaceship through a wormhole with a lot of mass or something or from outdated physics before quantum entanglement was known (and demonstrated) like it is today, or the holographic principle, or virtual particles, or hawkin radiation etc.
From what I've seen from modern physics and leading physicists there's no fundamental reason why going back in time is not possible, we just don't know how to do it practically yet with something with mass. Hawkin himself has changed his mind on this at least once, with the most recent opinion that it might be. It's a technical problem to potentially be overcome, not a fundamental fact or law of the universe (potentially!)
Stephen Hawking says time travel could be possible one day. Here's how l Opinion
(The article itself is shit, it's just his opinion it's here for)
Bloody hell how long did it take you to type all that!?!
Time travel theory/causality gives me major headaches.... you are giving me a friggin migraine!
I read (or maybe watched) something that described time as being fluid. So if you are involved in an event, something that could have repercussions in the future, and if you travelled back to that incident, you will only remember that incident as it happens.
So, let’s say that if it was future Burnham that travelled back to when the trap had been laid. Then she will only remember the events as they unfold, because she is part of the moment. She maybe aware of the trap, but because time is fluid the changes will not impact upon her until they reach her point in the future.