(ORDO NEWS) — Most likely, life on Earth was formed from amino acids and other basic ingredients that were delivered to the planet by meteorites. New experiments have shown that such substances are easily formed in space.
The young Earth was lifeless, sterile and constantly bombarded by meteorites. It is assumed that it was they who brought the first “building blocks of life” to the planet – substances whose chemical evolution led to the appearance of protocells.
Amino acids and other organic compounds are indeed found from time to time in some meteorites, such as the Murchison found in Australia . However, the question remains of where they came from on these celestial bodies.
Last year, Yoko Kebukawa and her colleagues at the National University of Yokohama showed that amino acids could be formed from the simplest and most common organic substances in space, such as formaldehyde and ammonia.
But such a reaction requires liquid water and heat. Theoretically, the source of this heat could be the decay of radioactive elements.
Aluminum-26 and some other unstable isotopes are also not uncommon in chondrites , the most common type of meteorites. In a new paper, Kebukawa and her co-authors tested this hypothesis.
The scientists dissolved ammonia and formaldehyde in water, sealed a glass container, and exposed it to gamma radiation from the decay of cobalt-60. Soon, glycine and alanine, glutamine, as well as some other amino acids that are not part of proteins, appeared in the liquid.
As the radiation dose increased, the concentration of these substances increased. Based on this dependence, the authors calculated that due to the decay of aluminum-26 in chondrites, amino acids could accumulate in quantities comparable to their content in Murchison in just 1000–100,000 years.
“In principle, the appearance of amino acids was not unexpected. However, the results were much more impressive both in quality and quantity.
A variety of amino acids arose under the action of gamma rays and in fairly significant quantities. Formed in the mother bodies of meteorites, then they could fall to the Earth and become the basic “building blocks” of life,” Kebukava noted.
The researcher added that similar processes could well “seed” the young Mars, then still quite suitable for the development of life.
And on some moons of the solar system – for example, on Enceladus – “local” amino acids could appear due to gamma irradiation of substances dissolved in the subglacial ocean.
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