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samudra
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- TL;DR Summary
- (my question is fed by various bodies of science-fiction involving FTL, instantaneous communication, 'thoughts', 'dreams', 'connections') and asks: Have we made progress in defining the nature of Time?
As a non-Physics major, like many others, I read science-fiction, hard science-fiction, have undergraduate/graduate courses on Astronomy and college physics. I also participated in R&D that produced electric rockets able to power small space vehicles (very slowly, but surely). I deal with satellite communications to GEO and LEO space vehicles and came up with a multi-hop method for hypothetically connecting Mars/Earth stations with each other with broadband speeds all of the time, regardless of the orbital geometry of Sun, Earth, Mars. Those were and are fun projects. What I have realized after looking at the work done few years ago, and trying to plot it on any sort of a big scaled 3-D plot, such networks are -- well -- big in any number of units, and if by the end of this century, the human race will begin to colonize outer space, there needs to be some consideration of the concept of Time.
Like a few sci-fi authors, I somehow intuitively (and perhaps through personal events) think that if humans are intentionally isolated in confined environments (Space vehicle in microgravity, under medication in ICU, incarcerated in a prison, in a space simulator) without contact, their sense of times become fuddled, and somehow they feel they have more time in hand to do things (like think, monastic astronomers in medieval times) yet time is actually plodding along just fine outside of that environment. Who wouldn't want to spend their entire lifetime dreaming up ideas, only to "wake up" and notice they have been asleep for a few minutes. Yet those memories / thoughts are apparently real to an individual. How can biologics have different senses of time when encased in a physical container, in a physical world in which regular time marches continously - yet they can regress to earlier childhood memories and go forward with visions of the future. Is time in a cosmological sense fixed in nature or not?
Separately if the universe is expanding continuously, and light speed is constant (is it?) - is there a possibility of finding a single event/location/phenomenon in Minkowski spacetime (Mikowski space) that observers in different part of this universe can agree on as a common spacetime reference? And if it was expanding from the moment after Big Bang (whenever that was) was the speed of light constant even then? If both are correct (the speed of light is constant, with lightspeed = distance/time) when was the "fundamental unit" of time [whatever that might be] different in the small compressed (possibly finite) volume after big bang than presently expanded (possibly finite) universe? Or, must the "fundamental unit" of distance [whatever that might be] have been different then compared to present? Or is it that the equation above is really too simplistic and ignores relativistic mehanics - as "spacetime" is a four dimensional manifold combining three-dimensional Euclidean space and "time", in which case for both cases can be true, lightspeed can be constant always as long as they are on different points on the manifold. Then - the question I am struggling philosophically, does that not mean in a given universe's spacetime, isn't it likely that the fundamental units of time are different at each point (= time scale is different) - or is this too much of a reach?
Like a few sci-fi authors, I somehow intuitively (and perhaps through personal events) think that if humans are intentionally isolated in confined environments (Space vehicle in microgravity, under medication in ICU, incarcerated in a prison, in a space simulator) without contact, their sense of times become fuddled, and somehow they feel they have more time in hand to do things (like think, monastic astronomers in medieval times) yet time is actually plodding along just fine outside of that environment. Who wouldn't want to spend their entire lifetime dreaming up ideas, only to "wake up" and notice they have been asleep for a few minutes. Yet those memories / thoughts are apparently real to an individual. How can biologics have different senses of time when encased in a physical container, in a physical world in which regular time marches continously - yet they can regress to earlier childhood memories and go forward with visions of the future. Is time in a cosmological sense fixed in nature or not?
Separately if the universe is expanding continuously, and light speed is constant (is it?) - is there a possibility of finding a single event/location/phenomenon in Minkowski spacetime (Mikowski space) that observers in different part of this universe can agree on as a common spacetime reference? And if it was expanding from the moment after Big Bang (whenever that was) was the speed of light constant even then? If both are correct (the speed of light is constant, with lightspeed = distance/time) when was the "fundamental unit" of time [whatever that might be] different in the small compressed (possibly finite) volume after big bang than presently expanded (possibly finite) universe? Or, must the "fundamental unit" of distance [whatever that might be] have been different then compared to present? Or is it that the equation above is really too simplistic and ignores relativistic mehanics - as "spacetime" is a four dimensional manifold combining three-dimensional Euclidean space and "time", in which case for both cases can be true, lightspeed can be constant always as long as they are on different points on the manifold. Then - the question I am struggling philosophically, does that not mean in a given universe's spacetime, isn't it likely that the fundamental units of time are different at each point (= time scale is different) - or is this too much of a reach?
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