[Physics] A question on the relativity of time effecting perception operating in two

[bendeezer]

[Physics] A question on the relativity of time effecting perception operating in two radically different gravity environments in our Universe.

Hey everyone,

I've been reading a copy of Eisenstein's Theory of Relativity off and on for a while now. I'm at best a layman with no traditional education in physics who just enjoys the subject. (At my own peril, I've been learning whatever I can, at my own pace from reading books and watching you-tube videos on the subject. Who knew it could be used for more than watching kittens play keyboards!)

Anyway, everyone talks about the relativity of time, and I've been having a hard time (in my head) of picturing the universe as it is operating in different pockets of time which seems to basically be generated by the motions and densities of matter. As the motion and/or density of matter increases relative to the speed of light, time slows down; and currently in a high motion high mass (deep gravity) environment represented by the “singularity†of black holes at least some physicists currently believe time just stops, and others just say our understanding of physics just completely breaks down at the point of “singularity.â€Â

Whenever this topic is talked about, this is always what they focus on, because apparently everyone who works with the concept wants to try to figure out how to go faster than light someday. (Given the vastness of space, I can't say I blame them.) But, what I can't find anyone at all talking about is what happens at the exact opposite end of the spectrum.

At what speed does time travel for a really small object that has little or no frame of reference to measure its motion except for photons zipping past it in every direction--and object basically moving at low speed relative to light in very (shallow gravity) Say for instance a single hydrogen atom floating in intergalactic space?

If you could shrink yourself down to that size, and still retain your ability to perceive the rest of the universe (let's also say even though you retain sentience, you're not biological, so rapid onset aging won't instantly kill you), what exactly would the rest of the universe look like?

I guess that time would be going very fast for you, and very slow for everything else. But, I don't know what that would look like.

In fact, if I imagine myself in a deep gravity situation looking outward at the universe, and then I put myself in a shallow gravity situation and look outward at the universe, it seems like time would always be perceived as moving at a constant (weather it is zipping by, or allegedly stopped) no matter what, but what I end up actually observing in the rest of universe becomes radically different based on these reference frames.

In deep gravity I think my field of view would be much greater, allowing me to see further afield and at higher resolutions than in shallow gravity. In deep gravity everything would be crisp and clear, maybe things would even appear closer than they actually are. But, accounting for the actual position of objects would become harder because of the extreme curves light would take to reach me in such situations would make them harder to trace back to the point of origin. Usually, whenever people talk about black hole situations they are focused on the effects of going ever deeper into them, they don't usually go into detail about what it would be like to turn around and look out from one.

OR---It might be that since light from different periods of time begin to hit you at the same time, maybe without dissipation. A black-hole might actually be brighter than anything else in the universe, on the inside looking out. So, bright that you couldn't expect to see anything but light.

And in shallow gravity everything would be skewed and blurry, perhaps not even recognizable as a universe full of galactic structuresâ€â€just fuzz, static, or fleshing lights; things in this environment might appear much further away than they really are, and being able to measure for distance I imagine would be near impossible, because you would not be able to identify anything with any clarity, especially with everything expanding away at faster and faster rates. In an intergalactic medium, I imagine that light would be experienced in flashes with ever increasing intervals of darkness in between. The darkness might actually be enveloping without much or any significant lensing effect caused by gravity.

Seems like an cosmic irony... you would think that putting yourself into a position of shallow gravity in intergalactic space would allow you to see more, rather than less, because there would be less things immediately around you blocking your field of view. And in or near black-holes you'd intuitively be expecting to see less, because of how everything gets all jammed up, your field of view would be blocked. But, it's actually just the opposite. Black holes are getting information overloads from all over the universe, and intergalactic space is likely not getting very much information at all about whatever is beyond it.

Anyway, I'm hoping someone with greater familiarity with relativity can tell me if I'm understanding/imagining these things correctly in my head. I don't nearly have a good enough grasp on all the physics equations involved in this situation, or inputing realistic values into the variables to hope for any accuracy. I struggle with newton and Einstein level physics, and don't even know any equations that deal with quantum mechanics. I mostly just want to know if I'm conceptualizing the effects of relativistic time in an accurate way on a intergalactic or universal scale. I'm pretty sure, my perception about the black hole situation is accurate, because lots of physicists talk about it... but no one ever seems to talk in much detail about how relativity works in the near nothingness in intergalactic space... and I would like to know more about that.

Also if anyone would like to walk me through the relevant equations to this topic, or post links to videos properly explaining the equations involved for understanding time relativity, that would be great.

[K^2]

You are picturing time in context of GR completely wrong. The two important concepts are map time and proper time. Map time is just a coordinate. It depends on your coordinate system of choice. It's not quite as arbitrary as, say, "Forward" direction in free space, but it can mix with any spacial coordinate to great extent. So it's entirely up to the observer what to choose as the time direction.

Proper time is time along your world path. This is literally the direction in space and time that you are traveling in. And while you always travel at the speed of light, direction in which you travel through space and time can change. Which, as an outcome, lets you cover different amount of space per unit of time. Ergo, have different velocity. But just like you can vary your velocity through space, your velocity through time also varies with that change of direction. And that's all there really is for time running slower or faster.

Now, as far as coordinate systems go, they aren't tied to any particular objects. We often choose coordinate systems related to some object, but they don't have to be. A larger, more massive object doesn't automatically get a "better", or "stronger", or "larger", or in any whatsoever way different coordinate system. You can choose to measure your coordinates with respect to a black hole or an electron just as easily. (Ok, so there are some quantum effects with the later, but you can take the exectation value.)

Finally, time doesn't go "faster" near a light object far from influences of gravity. Nor can you pick an object that's moving "slow". All speeds are relative. And so are the time dilations. Yes, if you are in deep space, and you receive a signal from Earth, it will appear to you that Earth's time is running a touch slow. And that is, indeed, due to Earth's gravity. Gravity is absolute. But it doesn't mean that all of the universe is running slower than you. It's just gravitational time dilation of Earth that's being involved. Wherever you are, you are moving really fast relative to something in the universe, and from their perspective, it's your time that's really slow.

[TheGatesofLogic]

one way i prefer to think of it is not pockets of altered time, since that impression can lead to a grsat deal of confusion, but rather as bending spatial coordinate lines. Say you are looking at your standard x v y v z coordinate space. Now suppose you have a gravitational source moving parallel to the x-axis but behind it (negative in z-units) and it is approaching the z axis (positive x motion). As the source approaches your coordinate system the system is twisted so that from your point of view it seems like the coordinate system no longer matches up with a coordinate system that you are in as the observer, if you take that "bending" of space and approach time in a similar manner you can somewhat visualize time dilation as a result of gravity by removing say east and replacing it with time as a coordinate line. This btw also helps with visualizing einsteinian geodesics which describe the shortest distance between gravitationally affected points

[bendeezer]

Thanks for the replies. I think I may have been confusing myself. Speed of light is constant (in vacuum), so the gravity illusions I was describing wouldn't be apparent regardless of time differentials, even though they do become apparent whenever a large gravity source is between you and the objects you are observing. (Gravitational lensing.) Anyway, thinks for your help but it will probably be a few more decades before I'm actually not so confused by it.