The matter and energy stored in the universe gather together and condense into a very small volume, with extremely high temperature and density, which instantly produces great pressure, and then there is the Big Bang. The reaction principle of this big bang is called quantum physics by physicists. The big bang dispersed the matter, the space expanded continuously, and the temperature dropped accordingly. Later, it appeared in all galaxies, stars, planets and even life in the universe.
Although the size of the whole universe is unknown, the size of Hubble's volume can be measured, and its diameter is estimated to be 93 billion light years. Among all kinds of multiverses, a universe is one of the components of a larger multiverse, and each universe itself includes all its space, time and matter.
Extended data:
The composition of the universe
The universe is almost entirely composed of dark energy, dark matter and ordinary matter. Others include electromagnetic radiation (estimated to account for 0.005% or close to 0.0 1% of the total energy of the universe) and antimatter. In the history of the universe, the proportion of all types of matter and energy has changed. In the past 2 billion years, the total amount of electromagnetic radiation generated in the universe has decreased by 1/2.
At present, ordinary matter including atoms, planets, stars, galaxies and life only accounts for 4.9% of the total mass and energy in the universe. At present, the overall density of such substances is very low, about 4.5× 10-3 1g/cm? , equivalent to the density of only one proton per 4 cubic meters of volume. The nature of dark energy and dark matter is unknown. Dark matter is a mysterious form of matter that has not been confirmed, accounting for 26.8% of the universe. Dark energy is energy from empty space, which leads to the acceleration of the expansion of the universe, accounting for 68.3% of the total universe.
Baidu Encyclopedia-Universe