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The closer we look at time, the stranger it gets

sciencefocus.com

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Re: The closer we look at time, the stranger it gets

#51

Post by nrhrjrjrjtntbt »

MaxikCZ wrote: post #38
ChuckMcM wrote: post #14

This was perhaps my favorite part of Physics 390 ("modern physics") which was about quantum dynamics and relativity. The speed of light is defined in terms of a velocity (~300,000,000 m/s) but if you were traveling at the speed of light time stops (which keeps the rule that its constant in all frames of reference). That and time passes more quickly at higher altitudes and these days we can actually measure that. Wild…

The fact that at speed of light time stops is just so bonkers to me. A photon is, from its point of reference, at the point of creation and at the point of destination at the same "time". Its literally seeing both parts of the universe at the same time, and since its traveled some distance over that time it cannot perceive, its essentially connecting 2 points in spacetime. If I understand it correctly, every photon e…

It sort of makes sense to me. It means effectively there is no speed limit. At least from the reference point of who is moving.

Re: The closer we look at time, the stranger it gets

#52

Post by tuyiown »

ricardobeat wrote: post #13
slyfox125 wrote: post #9

We understand "time" in the context that we must: to subsist in order to procreate. The extent it exists outside of our own perception as we imagine it does, is debatable. Ultimately, time is our sensory interpretation of the world around us to facilitate our survival and thus, we may never make sense of it outside the constraints it exists within.

We know empirically that time only flows in one direction, it can’t be described as just a perception. You’d have had at least the tiniest of evidence that time sometimes flows backwards.

> flows in one direction

_Everything_ flows in one direction, all particles goes in a straight line from their self reference, fields "modifying direction" is just an observer point of view. The separation of time and space is purely a perception matter.

A gross comparison would be to compare with objects perception, it only exists because our mind can leverage it for a strong evolutional advantage (I'm not only speaking of humans here).

Re: The closer we look at time, the stranger it gets

#53

Post by ndsipa_pomu »

smokel wrote: post #41
ndsipa_pomu wrote: post #36

Earlier quoted context omitted.

I bet Colin gets annoyed every time we point a telescope at far away objects as he has to rush around behind the scenes and paint in all the details.

Wait until you hear how he performs garbage collection.

Does it involve sweeping stuff under black holes?

Re: The closer we look at time, the stranger it gets

#54

Post by ben_w »

ndsipa_pomu wrote: post #35

One problem that I have with trying to understand "time" is that we can't measure how quickly it "flows" or at least how quickly we travel through it.

> we can't measure how quickly it "flows" or at least how quickly we travel through it.

I don't understand this, because it seems like "with a clock" is too obvious an answer, so surely you can't have meant what it sounds like it meant?

Re: The closer we look at time, the stranger it gets

#55

Post by My_Name »

They nearly have it in the article but don't take the next step, which is to realise that time is gravity. We are falling towards the future at the speed of causality. You can slow your experience of that by travelling really fast, or by being near something with a large gravity. Quantum particles can simply ignore gravity and time while we are forced to feel their effects due to our size, like a mote of dust can ignore gravity, but a brick can't.

Re: The closer we look at time, the stranger it gets

#56

Post by card_zero »

ben_w wrote: post #54
ndsipa_pomu wrote: post #35

One problem that I have with trying to understand "time" is that we can't measure how quickly it "flows" or at least how quickly we travel through it.

> we can't measure how quickly it "flows" or at least how quickly we travel through it. I don't understand this, because it seems like "with a clock" is too obvious an answer, so surely you can't have meant what it sounds like it meant?

If we say that seconds "pass", at what rate do they pass? Could they pass at some rate other than one second per second? That would entail outer seconds (second seconds, if you like). Which also have their own rate at which they pass, so now we need a third-level "flow of time", and so on.

So to say seconds "pass" is describing something else. They aren't moving.

Re: The closer we look at time, the stranger it gets

#57

Post by RobotToaster »

gyomu wrote: post #42
MaxikCZ wrote: post #38

Earlier quoted context omitted.

The fact that at speed of light time stops is just so bonkers to me. A photon is, from its point of reference, at the point of creation and at the point of destination at the same "time". Its literally seeing both parts of the universe at the same time, and since its traveled some distance over that time it cannot perceive, its essentially connecting 2 points in spacetime. If I understand it correctly, every photon e…

> A photon is, from its point of reference, at the point of creation and at the point of destination at the same "time" > every photon exists, from its point of view, for only infinitely small amount of time Why is that amount “infinitely small” and not 0 since photons travel exactly at the speed of light?

Existing for zero time would imply it never existed.

Re: The closer we look at time, the stranger it gets

#58

Post by throwaway77385 »

My_Name wrote: post #55

They nearly have it in the article but don't take the next step, which is to realise that time is gravity. We are falling towards the future at the speed of causality. You can slow your experience of that by travelling really fast, or by being near something with a large gravity. Quantum particles can simply ignore gravity and time while we are forced to feel their effects due to our size, like a mote of dust can ign…

A mote of dust doesn't ignore gravity in a vacuum ;)

Re: The closer we look at time, the stranger it gets

#59

Post by kburman »

MaxikCZ wrote: post #38
ChuckMcM wrote: post #14

This was perhaps my favorite part of Physics 390 ("modern physics") which was about quantum dynamics and relativity. The speed of light is defined in terms of a velocity (~300,000,000 m/s) but if you were traveling at the speed of light time stops (which keeps the rule that its constant in all frames of reference). That and time passes more quickly at higher altitudes and these days we can actually measure that. Wild…

The fact that at speed of light time stops is just so bonkers to me. A photon is, from its point of reference, at the point of creation and at the point of destination at the same "time". Its literally seeing both parts of the universe at the same time, and since its traveled some distance over that time it cannot perceive, its essentially connecting 2 points in spacetime. If I understand it correctly, every photon e…

Have a question related to this, if a photon has zero proper time between emission and absorption, how should I think about the influence of later-created photons or fields on it?

In our frame, we can interact with a photon long after it's emitted send it through a filter, bounce it off a mirror, measure it, etc. But from the photon's own “no proper time” perspective, does it make sense to ask how something created after its emission could affect its path?

Re: The closer we look at time, the stranger it gets

#60

Post by f3b5 »

tornikeo wrote: post #25

Not related to this article, but this post seems to attract so many cranks. Just look at other comments. The amount of weird (out-of-touch) comments on this post is fascinating.

Some of those might be AI accounts that found an ambiguous topic for upvote farming.
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