At present, the lowest temperature on the earth measured by human beings in the Antarctic reaches 89.2℃ below zero, but now people can make a lower temperature than this, such as liquid nitrogen made by human beings, which can reach MINUS 196 degrees Celsius, or even lower, which can reach MINUS 253 degrees Celsius. This temperature is also very shocking. Everything in the whole universe is made up of particles. The eternal motion of particles provides temperature for matter. The greater the kinetic energy of a particle, the higher the temperature of the object it constitutes, but the speed of the particle is limited. Relatively speaking, the kinetic energy of particles can be provided infinitely, and the temperature can be raised continuously, but the speed is limited after all.

At present, physicists have found that the temperature is as high as 32 degrees Celsius of 1.42× 10, which is equivalent to the instantaneous height of BIGBANG. And after BIGBANG, there was no such high temperature in an instant. Comparatively speaking, people have not found a higher temperature at present, so they can only create a higher temperature through quantum mechanics. If we want to keep the temperature low enough, we must make particles.

So how small can the minimum kinetic energy of particles be? Theoretically speaking, the kinetic energy of a particle when it is not moving is zero, and at this time, the kinetic energy of the particle is the smallest, and the temperature will also be the lowest. The corresponding temperature is called absolute zero, which is about -273. 15℃. Of course, this is only based on theory. Therefore, the temperature will not drop forever, and absolute zero is also the lower limit of existence, so the universe reached the highest temperature from the beginning.

But this absolute zero can't be achieved anyway. At present, the universe has cooled for 100 years, and now the average temperature of the universe is MINUS 270℃, which is a little higher than absolute zero. So people found a temperature close to absolute zero in their experiments. Why can't the temperature reach this point? According to the theory of relativity, there is no static frame of reference in the universe, and everything will move. Static is only relative. In quantum mechanics, examples will not stop moving forever, otherwise their positions will be accurately calculated, but this goes against the uncertainty of particles.

Therefore, the kinetic energy of particles will always be greater than 0, and the temperature will never get stuck above absolute zero. So the question is what will happen if the universe reaches absolute zero? When the temperature of the universe reaches absolute zero, neither relativity nor quantum mechanics can play a role in the universe, and even there is no such thing as space and time in the universe. If the universe is at absolute zero, all the energy in the universe will be consumed and there will be no energy in the universe.