Gamma rays help meteorites bring life to Earth

Meteorites at the beginning of the existence of the Solar system could bring amino acids to Earth, which were the “bricks of life”. A new study showed that the synthesis of these substances could occur under the influence of gamma radiation, which was formed as a result of radioactive decay.

Meteorites could bring amino acids to Earth. Source: NASA’s Goddard Space Flight Center Conceptual Image Lab

Amino acids in meteorites

Scientists from the National University of Yokohama, led by Yoko Kebukawa, made an interesting assumption about where organic matter could have come from on Earth, which launched the process of biological evolution. It is known that meteorites were formed from the primary material of the Solar System, they could contain components of life even before the conditions for its existence arose on Earth. 

Especially in this regard, scientists pay attention to a class of meteorites known as carbonaceous chondrites. They contain not only a large amount of carbon, but also water. In addition, ready-made amino acids can be found in their composition. Therefore, they can be their source on ancient Earth.

Previously, the possibility of synthesis of organic substances on meteorites has been repeatedly proven. In particular, the same Kebukawa team in a previous study showed that it is quite easy to obtain amino acids from ammonia and formaldehyde.

Gamma rays as an energy source

The only problem is that the synthesis of amino acids in this way requires heat and liquid water. Therefore, in a new study, scientists decided to check whether gamma rays could be a source of energy.

Their source may be radioactive decay. And the unstable isotope aluminum-26 can be found in meteorites. Theoretically, it can give enough heat to melt the ice and create conditions for the synthesis of amino acids.

For this, the scientists dissolved formaldehyde and ammonia in water and exposed them to radiation from a radioactive isotope. It turned out that a number of amino acids were formed, such as alanine, glycine, alpha-aminobutyric acid and glutamic acid; as well as beta-amino acids, such as beta-alanine and beta-aminoisobutyric acid, and an increase in the intensity of radiation positively affects their synthesis. 

Next, scientists investigated the Murchison meteorite, which fell in Australia in 1969. They calculate that gamma rays, which are formed as a result of the decay of its radioactive components, can form the number of amino acids found in it over a period of time from 1000 to 100 thousand years. This suggests in favor of the theory that meteorites could significantly affect the origin of life on Earth.

According to

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