In the past, scientists generally believed that Mercury, Venus, Earth, Mars and the Moon in the inner solar system experienced a period of intense bombardment by comets and asteroids, known as the late Heavy Bombing Period, about 4.1 billion to 3.8 billion years ago. On November 1st a new study showed that the late heavy bombing period occurred earlier, less intensely and for longer than thought. The discovery could influence theories about the origin of early Earth life.
The solar system was “bombed” more than 4 billion years ago.
The discovery of the late heavy bombing period began with the Apollo moon landing in 1969. The Apollo landed south of the Tranquil Sea. The so-called “sea” is in fact a meteorite impact on the moon, the moon’s crust is broken, magma overflow and condensation formed plains. Analysis of the composition of lunar sea rock samples collected by Apollo revealed that the moon had been hit hard by comets and asteroids, and by measuring rock sample isotopes, they believed that the period was between 4.1 billion and 3.8 billion years old. A large number of comets and asteroids bombarded the lunar surface to form a large number of craters, so the late heavy bombing is also known as the lunar disaster.
Subsequent studies have shown that the bombing did not occur in isolation, and that it was common within the solar system or even on Earth.
However, the study could have advanced the late heavy bombing to about 4.15 billion to 4.4 billion years ago. Researchers on Earth’s meteorite study found that Vesto was hit by multiple objects between 4.15 billion and 4.4 billion years ago, suggesting that the late heavy bombing period occurred earlier, less intensely, but for longer periods of time.
Why are meteorites on Earth proof that Veston was hit between 4.15 billion and 4.4 billion years ago? How can scientists determine that the meteorite was the one that hit Veston?
Ji Jianghui, a researcher at the Zijinshan Observatory of the Chinese Academy of Sciences, told Science and Technology Daily: “When a meteorite hits the surface of a planet, it explodes violently and leaves a deep hole in place, and the explosion will produce a large amount of meteorite debris splashing, and some meteorite fragments will continue to ‘travel’ in space, after tens of thousands of years, the chance coincidence fell on earth.” “
Through a series of measurements of the meteorite, the researchers found that it belonged to one of the HED meteorites. HED is short for three types of meteorites, Howardites, Eucrites, and Diogenites, all of which are thought to be from Vesta’s crust. “The difference between the three meteorites is only in the mother rocks from different geological and historical periods.” Ji Jianghui told reporters.
The theory of the origin of life on Earth may be rewritten
“The advance of the late heavy bombing period will influence the theory of the origin of life on Earth.” Ji Jianghui said that the traditional theory of the origin of life on Earth is mainly divided into cosmic life theory and chemical origin theory.
Chemical origin says it is believed that life on Earth evolved step by step from non-living matter through extremely complex chemical processes over an extremely long period of time after the Earth’s temperature gradually declined. It is generally believed that it is divided into four stages: first, the stage of generating organic small molecules from inorganic small molecules, that is, the chemical evolution process of the origin of life is carried out under primitive Earth conditions;
Cosmic life says that the earliest life on Earth or the organic matter that made up it came from other objects or interstellar dust in the universe — certain microbial spores that can attach to interstellar dust particles and fall into the Earth, giving the Earth its initial life molecules.
During the late heavy bombing period, the Earth was bombarded with comets and asteroids, creating a large number of impact craters. Comets and asteroids may be able to bring certain microbial spores to Earth at the same time as they are bombarded, giving the Planet a source of life. Ji Jianghui said: “The advance of the late heavy bombing indicates that microbial spores may also enter the Earth earlier, thus changing the traditional theory of the origin of life on Earth’s time.” “
Why does the moon have a lot of impact craters when it’s hit, and the Earth doesn’t? Ji Jianghui said: “The earth has wind, water, soil three ‘fill the pit master’.” “The movement of the wind carries a lot of sediment, and geological activity such as the Earth’s own volcanoes and earthquakes are likely to slowly fill the craters caused by the late heavy bombardment. Compared with the earth, the moon’s mass is small, which makes it difficult for the moon’s gravity to retain water, atmosphere and lack the energy necessary for geological activity, so it is not surprising that the moon has the natural conditions to retain impact craters.