Physicists have measured ‘negative time’ in the lab

[u/Shiny-Tie-126]

https://theconversation.com/physicists-have-measured-negative-time-in-the-lab-278996

[u/Actual__Wizard]

Homie, time is particle interactions. That's what duration emerges from... Interactions "take time." They do not occur instantly. This delay propagates through out the universe and is what we call "time." There's no such thing as negative time. The interactions "take time." The system of synchronization that humans use to get to work "on time" is not "quantum time."

[u/translunainjection → u/Actual__Wizard]

The speed of light is actually the speed of time, light just happens to always travel at it.

[u/liquid_at → u/translunainjection]

I've understood it as the fastest possible change of position in the universe. one plank length per plank time. Shortest possible distance that isn't the same location in the shortest possible time that isn't the same spot in time.

You can always change location less often, but never more often. Even if you would, the universe would not take notice of it.

[u/translunainjection → u/liquid_at]

TIL, that's incredible!

https://www.wolframalpha.com/input?i=1+plank+length+%2F+1+plank+time

Profound cosmic scale definition meets profound quantum scale definition.

[u/liquid_at → u/translunainjection]

it's how planck made the definition. speed of light is in the formular.

Gravitational Constant, Speed of Light and Planck Constant (describing the relation between wave length and energy) So, it's not surprising you found the speed of light in there.

[u/FrankScabopoliss → u/translunainjection]

Well, no, it’s the maximum observable speed of information, energy, or matter in the universe.

Light is not the speed of time, as time is just another dimension we can use to define the state of the universe.

In fact, you can’t use the word “speed” without time, because speed is distance over time. Saying the speed of light is the speed of time is nonsensical.

[u/Srnkanator → u/translunainjection]

What happens when something has so much mass that light is captured?

Is time also captured?

If time is captured and not allowed to move, does that mean a black hole, once formed, stops the universe for continuing at that point?

[u/translunainjection → u/Srnkanator]

Yes, I think, sort of. Time slows down near a black hole - remember Interstellar? Asymptotically slower the closer you get to the event horizon. From an external reference frame, anyway. Afaik, if you watch something fall in (for a big, non-spaghettifying event horizon), it gets slower and slower until it appears to stop, then its light slowly fades.

It gets weirder inside the event horizon - time and space switch places somehow and that's where I get lost.

And there's some information theory where black hole event horizons erase the information of whatever falls in from the universe.

[u/Klaeyy → u/translunainjection]

I think there is also a theory to deal with the problem of destroyed information, that Information is „saved“ on the „surface“ of a blackholes event horizon. Where instead of falling into it, its ever slowing passage of time sort of causes the information to be compressed/encoded onto the event horizon itself. Which prevents the Information from being destroyed.

[u/Actual__Wizard → u/Klaeyy]

No, it just falls in and the particles get destroyed. That doesn't mean their energy goes away. I don't know what the big hang up with that is. We already know that some of the energy leaks out as hawking radiation, so I don't really understand the point of confusion there.

It's just a massive object that has a massive gravitational pull and even particles like photons fall into it. The object itself should look like a super flat ball.

[u/FyreWulff → u/Srnkanator]

A black hole is so massive that when you're inside of one, time and space switch places, so as you approach the singularity you are moving through time. If you were in a big enough black hole, if you were to turn around and look outside the event horizon, you would be watching the universe go in fast forward.

[u/Actual__Wizard → u/translunainjection]

The speed of light is actually the speed of time, light just happens to always travel at it.

I'm pretty sure you're close to correct or correct.

[u/DrSitson → u/Actual__Wizard]

Because it is correct, just simplified. Speed of causality.

[u/Actual__Wizard → u/DrSitson]

Well, I know as a fact that I have written down in the unpublished paper "the theory of interaction," which is now going to be pushed off for decades because of the discovery of dark energy, but I know that I wrote in there that I believed that the speed of light is "the maximum rate of interaction."

But, yeah that's in the garbage can because of dark energy. Obviously there's more to the universe than we know and there is something for effects like gravity to propagate through because space is not actually emptiness. There's still dark energy in it.

Which, I'm pretty sure that "dark energy" is nothing more than energy that is "not concentrated into one location adequately to form into a particle sized object." The core compression holds all of the little pieces of it together. One the particle breaks apart, it takes a lot of energy to "put it back together."

[u/DeterminedThrowaway → u/Actual__Wizard]

I mean, give the scientists working on this some credit. They understand that concept and your dismissal of negative time using that basic of a concept is really hand-wavy and doesn't capture what they're actually saying

[u/Actual__Wizard → u/DeterminedThrowaway]

I mean, give the scientists working on this some credit.

I am, they did great work, but came to the wrong conclusion. Their conclusion doesn't "make logical sense." The method of action is not "negative dwell time." The object was accelerated.

[u/DeterminedThrowaway → u/Actual__Wizard]

The arrogance of saying that they came to a wrong conclusion based on such a simplified understanding is astounding. You aren't even talking about the same sort of thing as they are, because they're working with a statistical average that can happen to be negative. They weren't sure if a negative statistical average turned out to mean anything physically, and it does. That wasn't "the wrong conclusion", it was the whole point of the experiment. It just doesn't overturn the standard model or mean time travel, and they're not saying it does.

[u/Actual__Wizard → u/[deleted]]

Sure, a photon is composed of energy, and another effect accelerated it. You're talking about the speed of light in a vacuum and that's not what the experiment was.

Obviously we can observe photons being accelerated towards black holes, so it's totally normal and occurs constantly.

[u/Actual__Wizard → u/[deleted]]

Photons always travel at c.

Looks at an image of photons falling into a black hole.

You're not correct.

I'm sorry, but you have to square that up. Either they always travel at C and the space is warping (it can't because it's not a thing), or space is nothing, and their speed is not as constant as you are suggesting.

Which, obviously photons do not all travel at the same speed... We know that as fact...

Reminder: Photons are made of the same energy that everything else is, there's nothing "special about them that causes them to ignore velocity changes." If they interact with something, then that's what happens...

[u/Actual__Wizard → u/[deleted]]

See my edit.