Is there any ancient Chinese imagination of the universe?

1.The ancient Chinese believed that "the sky is round and the earth is square", that is, the sky is round and the earth is square.

2.It is believed that "the sky lacks the northwest and the earth sinks to the southeast", that is, the northwest corner of the sky is incomplete, and the earth sinks to the southeast, which is mainly based on the phenomenon that most of China's rivers flow from the northwest to the southeast.

3.In addition, the so-called universe was interpreted by the ancients as "the upper and lower four directions are the universe, and the ancient and modern are the universe".

The universe is the most thorough free lunch.

Excerpt from "A Brief History of Time" Stephen Hawking.

The idea of inflation also explains why there is so much matter in the universe. In the universe that we can observe, there are roughly 100 billion, billions (1 followed by 80 zeros) particles. Where do they come from?

The answer is that in quantum theory, particles can be created from energy in the form of particle anti-particle pairs. But this only raises the question of where the energy comes from. The answer is that the total energy of the universe is exactly zero.

The matter of the universe is made up of positive energy; However, all matter is attracted to each other by gravity. Two pieces of matter that are close to each other have less energy than two pieces of matter that are very separate, because you have to expend energy to overcome the gravitational pull that pulls them together to separate them. In this way, the gravitational field has negative energy in a certain sense.

In the case of a universe that is roughly the same in space, one can show that this negative gravitational energy just cancels out the positive energy represented by matter, so the total energy of the universe is zero.

Twice as many as zero remain zero. In this way, the universe can double its positive material energy and negative gravitational energy at the same time, without breaking its conservation of energy. This did not happen during the normal expansion of the universe.

At this time, when the universe grows larger, the energy density of matter decreases. However, this did happen during the boom. Because when the universe expands, the energy density of the supercooled state remains the same:

When the volume of the universe doubles, both the positive matter energy and the negative gravitational energy are doubled, and the total energy remains zero. In the inflationary phase, the size of the universe increases by a very large multiple. In this way, the total energy that can be used to make particles becomes very large.

As Guth said, "It is said that there is no such thing as a free lunch, but the universe is the most thorough free lunch." ”

A black hole is called a black hole because it is infinitely dense and eats everything (including light), so it appears black. The fate of the development of massive stars. Massive (tens to hundreds, thousands of times the mass of the Sun) fusion fuel depletion (h-he-c-o-..

fe-..After that, there was not enough pressure inside to withstand the gravitational pull of the surface and the core, and the fragments contained various elements, some of which came to the sun and were captured by the sun's gravity, forming the earth, the solar system. And the density of the core of a star is infinite, which becomes a black hole.

The seven types of universes imagined by man.