What is Time and its behavior in different instances?

[ishan28mkip]

Recently I started reading on thermodynamics and from it only I saw that utilizing the second law of thermodynamic we could define the arrow of time. And not only the arrow but we could also try to define time utilizing the second law. We could state, that time is used to sequence events where there is change of entropy.

This is also evident in already major theories such as that relating to the heat death of the Universe wherein once the Universe reaches the state of maximum entropy, time breaks down. Because at a equilibrium, only quantum particles would be left whose density would fluctuate from region to region but no consolidate change would happen in the universe hence time will make no sense in such a scenario.

Now coming to the second part of my question, that is how time behaves in different circumstances.

I know that behavior of time may be found out by results of the general theory of relativity.
But I would like a discussion or clarity,

1. That what is time inside the event horizon of a black hole
2. On or inside the singularity of a black hole
3. Assuming the end of the Universe is a heat death, will time break down as I have mentioned above or will only the sense of time break down and time will still be there.

Finally, Could someone also help me with the concept of black hole entropy, it is stated that the black hole entropy is directly propotional to its surface area. Can someone give an example of a body being pulled in the black hole.

 

[Valerie Park]

Time behaves differently under different circumstances due to the effects of gravity, which are described by the General Theory of Relativity. Near a black hole, time passes more slowly relative to more distant observers. This means that an object falling into a black hole would experience time dilation and time would seem to pass more slowly for them relative to an observer outside the black hole. Inside the event horizon of a black hole, time has no meaning because the gravitational force is so strong that even light cannot escape. On or inside the singularity of a black hole, time does not exist. The singularity is a point of infinite density and space-time curvature, where all physical laws break down and no information can escape. Assuming the end of the Universe is a heat death, time will still exist, but it will be meaningless. As the entropy increases, the universe will become increasingly homogenous and chaotic, and events will become less and less distinguishable from each other. Without any changes to measure, time will have no meaning. Black hole entropy is related to the surface area of the black hole's event horizon, which is proportional to the black hole's mass. This is known as the Bekenstein-Hawking formula. For example, if a black hole with a mass of one solar mass (about 2 x 10^30 kg) were to be pulled in, its entropy would be proportional to its surface area, which would be equal to the area of a sphere with a radius of about 3 kilometers.