What is time?

Question

like obviously time as we kno in earth doesnt apply out in space. so wat exactly is time in space? is there a definite unit? or does it exist always as a relative to something else?

Answer 1

Time is a measuring tool used by man to measure 1) motion, 2) the length of an event, or 3) the length between events.

Time in space is relative. That is why it is termed space/time. However, the unit itself remains constant. That is, if one on a planet is viewing their wristwatch, one second goes by. Another person travelling in a spaceship going 1/2 the speed of light looks at their wristwatch and perceives one second go by. Even though there may be differences between the two speeds of the wristwatches (as we know, the person on the planet would be aging more rapidly) there is no perceived difference for the two people- no speeding up nor slowing down of time. If the person on the spaceship were to return to the planet he would be shocked to discover that the planet people had aged more because time on his wristwatch was going by in normal mode.

Time is dilated in two known ways. Velocity induced dilation and gravity induced dilation. These effects have been studied and tested since the 1940's and have been proven to exist. The Lorentz transformation describes time dilation. General relativity is used for gravity dilation. Special relativity is used for velocity dilation.

In velocity induced dilation, effects are noticed at speeds as 'slow' as 1/10 the speed of light. The effects would be cummulative (the longer one traveled at a high velocity, the more difference compared to the home planet).

For gravity induced dilation, clocks at lower potentials in a gravitational field — such as in close proximity to a planet — are found to be running slower.

An observer at the top of a tower will observe that clocks at ground level tick slower, and observers on the ground will agree. Gravitational time dilation is agreed upon by all stationary observers, independent of their altitude.

This means that persons on Earth for instance would seem to age slightly slower than a person on board the International Space Station.(even though neither persons wristwatch would appear to speed up nor slow down. When the person on the ISS returns to Earth, only then would he realize that his wristwatch would need to be reset back a few seconds to match Earth time.)

The Global Positioning System can be considered a continuously operating experiment in both special and general relativity. The in-orbit clocks are corrected for both special and general relativistic time-dilation effects so they run at the same (average) rate as clocks at the surface of the Earth.

This is what is meant when it is spoken that black holes not only curve space but in fact space/time.

Answer 2

That is interesting, and perhaps a question that we will never know the answer to. I do know that time is relative, that the only thing constant is the speed of light, everything else is relative. But maybe light needs time, because if there was no time, there would be no speed, only distance, or not even that, because distance divided by zero is undefined.

I have read books that use the term "arrow of time," that it is like an arrow always pointing and traveling in one direction. But maybe if everyone "turned off the lights" we wouldn't be able to "see the arrow" and time would stop.

Answer 3

Time actually do apply in space. But it is called space-time. If the big bang theory is correct. Then time started the moment that the big bang occurred. I believe that time always existed since it is something that you can't see, touch, taste etc. We only realize its passage once we are able to understand it. Newly born Babies have no concept of time because their minds are too young to understand it. It is indeed a concept but we measure it using the things within our environment.

Answer 4

Time and space are both infinite which is difficult for all but the greatest minds to cope with. And from all the gobbledegook that comes out of science fiction and pseudo-science, one can almost choose what he wishes to believe. For instance, is time really a dimension? The 4th dimension? We can measure history with it with certainty, but not the future with certainty. Science says that as our velocity increases, relative to those we left behind, so does time slow, to us.
Since the Big Bang expelled us outward at near the speed of light, how fast are we now going and how does that affect our aging? (Science now tells us our rate of outward velocity is increasing.)
To humanoids expelled in the opposite direction from our Big Bang, and we must acknowledge that possibility, I think we must also suppose that they are in the same time frame as us, but in the opposite imaginary arc of the great sphere that is expanding in all directions. Maybe a little food for thought?

Answer 5

1 second = the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom at 0 degrees K and without outside interference. -Wikipedia

But, as you move, your space-time frame of reference changes, so no, time is not always constant.

Answer 6

"The fire in which we burn" haha but seriously,

I think there is such a thing as absolute time. I like to think of it like Wittgenstein with a few variations. Time is like a ring traveling along a band of wire. Certain things may alter the speed at which the ring travels, (such as gravitation etc) but it has definite direction.

Answer 7

Time is the measurement
of the duration of an event.
In my opinion, time itself does
not exist as an entity unto itself.

Answer 8

Time is relative.
It depends on the observer system of coordinates position and speed, relative to another system of coordinates.

Answer 9

Wow that's such an interesting question, I never would have even thought of that if I hadn't seen your question. Sorry but I don't know the answer haha I don't think anyone does really, but that's almost kind of scary to think about.

Answer 10

What is time?
Time is when a man is trying to make time with your woman, but you're doing time behind bars and your time is standing still