Where did life on earth originate, from the universe or the surface?

According to records, Aristotle may be the earliest explorer of the mystery of the origin of life. More than 300 BC, he proposed that human life can arise naturally from non-living matter. This is the famous theory of autogenesis of life. It has led many scholars to believe that life can arise directly and rapidly from non-living matter or other organisms. The earth was born. This view dominated the biological world for more than 1,000 years. As late as the 13th century, people still believed that sheep could grow from trees. At the beginning of the 17th century, the Belgian doctor Van Helmont also proposed that mice could be born by fermenting shirts soaked in human sweat with wheat.

In the mid-17th century, the Italian doctor Reddy used experimental methods to discover that flies and other organisms are not naturally generated, but are born from the eggs of their parents, thus denying the theory of autogenesis and establishing the theory of panspermia. , believing that all living things come from similar creatures. However, autogenists still adhere to the original view and believe that although flies cannot occur naturally, simple organisms such as microorganisms can occur naturally. It was not until 1864, when the French chemist and microbiologist Pasteur's famous sterile immersion experiment and gooseneck bottle experiment came out, which confirmed the view that microorganisms cannot occur naturally, that the theory of autogenesis was completely denied and biogenesis was established. Argument. But where did the first life on Earth come from? This question is reminiscent of the old joke about the chicken and the egg. The theory of autogenesis and the theory of panspermia are also a question of whether the chicken came first and then the egg or the egg came first and then the chicken.

In the late 19th century, some scholars proposed the hypothesis that life comes from the universe. It is believed that life on earth was formed by the embryos of life from space falling into the earth's surface. Because it was later discovered that ultraviolet rays and cosmic rays in sunlight have strong lethality to kill life, people abandoned their trust in this theory. At the beginning of the 20th century, the theory of the chemical origin of life emerged in the primitive surface ocean. Its founder was the former Soviet biochemist Obalin. He published many monographs to prove this theory, and elaborated on the evolution of life from inorganic to organic and from simple to organic. to complex chemical evolution. In 1953, American scholar Miller successfully synthesized a variety of living organic molecules such as amino acids using inorganic substances and simple organic substances as raw materials in the laboratory, and later successively synthesized complex living polymers.

These have provided new evidence for the theory of chemical origin, making many people accept this view without doubt.

In the 1960s, Cairns Smith, a chemist at the University of Glasgow in Scotland, proposed a new theory of origin based on the theory of chemical origin, the soil theory, which believed that life is made of fine-grained soil with a special structure. generated. Recently, NASA scientists have also discovered that the energy contained in ordinary soil can allow inorganic substances to be synthesized into organic matter, and even the basic organic substances necessary for life can be synthesized. This discovery is undoubtedly a strong support for the soil theory, and also explains the dehydration problem when small molecules of life such as amino acids synthesize high molecules of life such as proteins. It should be said that this theory is a big step forward than the view of chemical origin.

After the 1960s, the application of radio astronomy technology enabled scientists to discover a large number of organic molecules in the universe, especially in and near large nebulae, triggering people to rethink the theory of life in the universe. Around 1980, British astronomer Hoyle and others proposed the idea of ??a new theory of life in the universe. In his book "The Intelligent Universe", he proposed that not only life embryos exist in the universe, but also that life on earth may be related to intelligent organisms in the universe, further emphasizing the role of extraterrestrial organisms in the formation of life on earth.

Where did life on earth originate, from the universe or the surface? This is an issue for which it is difficult to draw a clear conclusion in the near future. Although the chemical origin theory has the upper hand among many hypotheses, the discovery of organic molecules in space, organic molecules in meteorites, and many other signs that can indicate the existence of life in the universe also require a reasonable explanation from the chemical origin theory on the surface.

According to research by geologists, the environment in which primitive life emerged simulated in the theory of chemical origins is just a conjecture, and all assumptions about the chemical processes of synthetic life are just accidental phenomena that occur under certain specific conditions. , there is no inevitability. The fact that organic molecules exist in the universe it faces makes it difficult to get out of the predicament in the near future. Of course, we cannot blindly believe in the hypothesis of life in the universe now. To say that life on earth comes from the universe, more definite evidence needs to be found.

Besides, the harsh environment in the universe and the high temperature friction of the atmosphere make it difficult for us to believe that it has the conditions to produce life.

Where did life on earth come from? Human beings are still unable to give a reasonable explanation.