The ancient Greeks had two words for time, chronos and kairos. Kairos is an ancient Greek word meaning the right or opportune moment (the supreme moment depending on who is using the word).

While Kairos signifies a time in between, a moment of indeterminate time in which something special happens, refers Chronos to chronological or sequential time.

While Kairos is qualitative, Chronos has a quantitative nature.

Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to
quantify rates of change such as the motions of objects. The temporal position of events with respect to the transitory present is continually
changing; events happen, then are located further and further in the past. Time has been a major subject of religion, philosophy, and science.

Aristotle believed that space was finite because of the impossibility of an actual infinite quantity. The way this would work is, if we are unable to imagine an infinite quantity, and if the most real is the most knowable, then the unknowability of an actual infinite quantity means that it cannot
be real. On the other side, the Skeptics argued that space cannot be finite because we can imagine space on the other side of any boundary. This means that where the boundary is is arbitrary, which violates the Principle of Sufficient Reason, i.e. there is no reason why the boundary should
be where it is. More vividly, they imagined Hercules punching out the boundary.

Time is not just to read to periodic motions such as from the radiation in an atomic clock - it does still matter where the clock is. And if that was
not enough,
then asked the founders of quantum mechanics that time periods that are shorter than 5,4 x10-44 second (a 5 which is 44 places
behind the
comma) by definition can not be measured. From that limit the spacetime is become a grainy foam, where about no statements can
be done.

Time is being influenced by space and gravity.


Augustine (354-430) ruminates on the nature of time, asking, "What then is time? If no one asks me, I know: if I wish to explain it to the one that asks, I know not." He begins to define time by what it is not rather than what it is, an approach similar to that taken in other negative definitions. However, Augustine ends up calling time a “distention” of the mind (Confessions 11.26) by which we simultaneously grasp the past in memory, the present by attention, and the future by expectation. Time is an extension, but from which is not known
Isaac Newton (1643-1727) is reasoning that the absolute, true, mathematical time flows by itself, due to his own nature, entirely evenly without reference to something external. And the time that we measure and use is one another.

That time, or better time period, is defined with reference to periodic movements. So we call the orbit of the earth around the sun a year. The period during which the earth rotates on its axis is called a day, and to make sure that there are still full days in a year, we gather about every four years an extra day.

The module of the system of hours, months, days, years, is now the second, and is since 1967 to measure with ultra-precise atomic clocks.

Kant proposes that space and time do not really exist outside of us but are "forms of intuition," i.e. conditions of perception, imposed by our own minds. This enables him to reconcile Newton and Leibniz: agreeing with Newton that space is absolute and real for objects in experience, i.e. for phenomenal objects open to science, but agreeing with Leibniz that space is really nothing in terms of objects as they exist apart from us, i.e. with things in themselves. Kant does not think we can know, or even imagine, the universe as either finite or infinite, in space or in time, because space and time are only forms of perception and cannot be imagined or visualized as absolute wholes. The universe, as the place of things in themselves, is not in space or in time and so is neither finite nor infinite in space or in time.
Albert Einstein (1879-1955) had put forward a different notion of time.

First, he showed that clocks run slower in (imaginary) missiles, rushing with almost the speed of light. Then he coupled his general theory of relativity of time in three spatial dimensions.

Together they are in theory the space-time, that under the influence of gravity can bend and curve.

Sometimes just a little, but still: atomic clocks on the earth's surface according to Einstein's theory run slower than atomic clocks high up there. And in practice, such as GPS systems, they do indeed.



It would be the trip of your life: traveling through a wormhole and then in the immediate vicinity of Pluto or in a galaxy millions of light years removed trap. Now you can see what an epic journey through a tunnel in space-time might look like, thanks to an animation by astrophysicist Andrew Hamilton of the University of Colorado at Boulder.
First, create a free fall through the outer horizon of a black hole. Once you've reached the inner horizon, you see an infinite-energy flash of the outside world with a picture of the entire history of the universe. In a real black hole you would burst, but for the visualization we now just assume that you have superpowers to survive this.

If you walk through the black hole, you come into a wormhole where the flow of power from the space around you turns and accelerates you back outside. The wormhole ends at the entrance of a white hole, which is a time-reversed version of the hole is black. Instead of inwardly is controlled space to the outside at a speed faster than the speed of light. Soon you will experience another flash of radiation, this time with a picture of the whole future of the universe.

As you move the white hole, you see third flash of light when you reach the outer horizon. This time there appears a new universe, containing an image of his entire past. While the camera, you will see the white hole you came out and a picture of the old universe. This is as close as we are now if we want to travel through a wormhole, but new theories of gravity can make such a journey in the future might be possible.