The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. An isolated system is one that does not exchange energy or matter with its surroundings. The universe is thought to be an isolated system, so the second law applies to it.
When stars die, they release their energy into the universe. This energy can be used to create new stars and planets, or to power other processes. So, even though stars die, the total energy of the universe remains constant.
However, the entropy of the universe does increase when stars die. This is because the energy released from dying stars is spread out over a larger volume of space. This means that the energy is less concentrated, and therefore more disordered.
So, even though the universe will eventually be devoid of stars, the total entropy of the universe will still continue to increase. This is because the energy of the universe will continue to spread out and become more disordered.
This process is known as the heat death of the universe. It is a hypothetical scenario in which the universe reaches a state of maximum entropy. In this state, all of the energy in the universe will be evenly distributed and there will be no free energy available to do work.
The heat death of the universe is thought to be billions or trillions of years away. It is a very long time horizon, but it is something that physicists and cosmologists think about.
To answer your question directly, the total entropy of the universe will not decrease when all the stars die. It will continue to increase, albeit at a slower rate.
Oct 02, 2023