How many mass extinctions have the earth experienced since its birth?

Some people speculate that life has been born several times in the 4.5 billion-year history since the birth of the earth. Mainly experienced five mass extinctions, the first was 500 million years ago, the second was 350 million years ago, the third was 230 million years ago, and the fourth was 65.438+800 million years ago. It reappeared after the Great Extinction, the last time happened 65 million years ago. Some people infer from the nuclear reactor discovered 2 billion years ago that there may be advanced civilized creatures on the earth 2 billion years ago, but unfortunately they were destroyed by a nuclear war or catastrophic natural disasters. In short, when the solar system moves to a specific position in space, environmental conditions that are not suitable for human survival will appear periodically on the earth, such as the periodic change of the earth's climate and the periodic disappearance of the earth's magnetic field. And the previous advanced civilization will be extinct, and then it will lead to the periodic origin and evolution of advanced intelligent creatures. The extinction of dinosaurs 65 million years ago is an example.

Interestingly, recently, according to the historical data of small celestial bodies hitting the moon mastered by Apollo program, Dr. Guy Fokerman of NASA confirmed the reliability of the above viewpoint by studying the mode of small celestial bodies hitting the earth. It is believed that there were several times of life on the earth about 3.5 billion to 4.5 billion years ago, but there were also several collisions between planets and meteorites. Asteroids collide violently at a speed of about 18 km per second. In addition to this large-scale influence, medium-scale influence often occurs. These effects may lead to the rise of geothermal energy, the evaporation of seawater, the melting of the earth's surface, the disappearance of life and the rebirth of life after hundreds of millions of years. Only creatures living in the deep seabed can survive. The creatures found in the deep seabed at present may be the ancestors of the whole life on earth.

Therefore, before the formation of our generation of civilization, there were probably some highly developed civilized societies on earth.

Suppose there is a population explosion on the earth, the whole ecology is unbalanced, all kinds of resources are exhausted, or all countries are expanding militarily and manufacturing and storing a large number of nuclear weapons. One day, some war maniac will start a war and detonate these nuclear weapons, and the earth will become the graveyard of mankind. Millions or tens of millions of years later, when the earth adapts to human existence again, they may begin to develop from a new primitive society, slave society and feudal society to a progressive society.