Since perpetual motion machines don't exist, why can celestial bodies keep running?

Perpetual motion machine can be said to be a joke in the history of human scientific development. Once upon a time, countless inventors enthusiastically devoted themselves to the research and manufacture of perpetual motion machines.

There have been many famous ones in history? Perpetual machine? But it turned out to be wishful thinking. Speaking of it, it was a long time ago that the perpetual motion machine became hot. As early as more than 200 years ago, the French Academy of Sciences passed the resolution of never accepting the application of perpetual motion machine, which marked the end of human confirmation of perpetual motion machine.

But after that, there are still some so-called? Scientists? Under the banner of perpetual motion machine to realize their own interests, some ended up in prison, and some were cited as a joke. So, is perpetual motion machine really impossible to realize? There is no doubt about it. With the discovery of the law of thermodynamics, human beings have completely ended the perpetual motion machine.

What is a perpetual motion machine and why can't it be realized?

It is easy to misunderstand from the name that perpetual motion machine is a machine that moves forever. Actually, it's not. If it is as simple as that, many things can be called perpetual motion machines. Generally speaking, perpetual motion machines can be divided into two types. The first is that they can continue to do work without any external energy.

This is a truth that even junior high school students can understand, which violates the law of conservation of energy. The law of conservation of energy is the core law of the whole physical system. Overturning the law of conservation of energy is equivalent to overthrowing the whole physics system in a sense. Numerous theoretical studies, experiments and practical applications have proved the correctness of the existing physics system. Because the first perpetual motion machine violated the law of conservation of energy, people began to focus on the second perpetual motion machine.

What is the second perpetual motion machine?

The so-called perpetual motion machine of the second kind means that it can continuously do external work with only a single heat source. This obviously violates the laws of thermodynamics. The second law of thermodynamics contains two important contents. One is that the temperature cannot be transferred from a low-temperature object to a high-temperature object without other effects.

Just like we put a cup of hot water in a house, the water will gradually get cold, instead of the room temperature dropping and the water getting hot. The second law of thermodynamics also includes that it is impossible to obtain heat from a single heat source and completely convert it into useful work without other effects. Therefore, it is impossible for all machines to completely convert energy into efficiency. We always talk about improving the conversion efficiency of machines, but this efficiency will never reach 100%. Both the principle of entropy increase and the law of conservation of thermodynamic energy determine that neither the first generation perpetual motion machine nor the second generation perpetual motion machine can be realized.

Since perpetual motion is impossible, why does the celestial body seem to keep running, while the universe seems to be eternal?

First of all, it must be clear that the perpetual motion machine and the operation of cosmic objects are completely different. Secondly, neither the celestial bodies in the universe nor the universe itself are forever running and lasting. On the surface, it seems that nothing provides energy for everything in the universe, but in fact, the energy of the whole universe comes from the Big Bang at the beginning of the universe. Of course, some people may not believe in the Big Bang theory, so we can put it another way, that is, everything in the universe comes from pure energy at the beginning of the universe.

So where does this pure energy come from? No one knows, and it is impossible to know, because the laws of physics did not exist before the birth of the universe, so everything can't be explained by what we know.

Everything in the universe runs from the pure energy at the beginning of the universe, so the universe is not eternal.

All celestial bodies in the universe have life cycles, stars will run out of fuel and collapse, and the universe itself will come to an end. We believe that the universe is eternal, because human life is too short in the time scale of the universe. There are many different views on how the universe ends. Some people think that the universe will collapse after expansion, and eventually the whole universe will collapse back to the state before the Big Bang, that is, time, space and everything in the universe will return to singularity.

There are also views that the entropy in the universe will reach the maximum one day, when all the substances in the universe will decay into leptons and photons, and the whole universe will be in the lowest energy state and reach thermodynamic equilibrium. At that time, the universe was like an empty and cold dead sea, which was the final outcome of the universe. We are not sure how the universe will eventually end, but it is common sense that life in the universe also has an end.