For the first time, all five base points from which life on Earth could have originated have been found in meteorites.

One version of the panspermia hypothesis suggests that comets, asteroids, or meteorites brought biological life to Earth. In fact, scientists previously found several organic compounds in meteorites that fell to the earth in the past, including three basic factors in the formation of DNA and RNA: the nitrogenous bases adenine, guanine, and uracil. What remained was the discovery of previously difficult-to-detect cytosine and thymine bases, and the question of the extraterrestrial origin of life shines with new colors. And it seems to work.

Image source: NASA Goddard / CI Lab / Dan Gallagher

Traditionally, organic compounds in a meteorite material were studied using highly heated formic acid. The crushed portions of the meteorite were placed in acid and after all the organic was dissolved there, analysis was performed. Nitrogen-containing bases adenine, guanine, and uracil, which belong to complex purine molecules, were found in meteorite samples without major difficulty, while the other two key compounds, cytosine and thymine, were not found as simpler pyramidal molecules.

In the new study, the researchers used a cold-water-based solution to dissolve the organic matter in the meteorite material. In addition, equipment was used for the analysis that allows the molecular composition to be examined with a sensitivity of the order of magnitude or even two orders of magnitude. The new approach was justified: for the first time, both cytosine and thymine were found in samples from three meteorites. This confirms that all five basic elements of DNA and RNA formation may have arrived on the young earth with cosmic bodies.

Scientists hope to study matter from asteroids delivered to Earth using automated Hayabusa2 and OSIRIS-REx stations in a similar way. This is a pure scientific experiment because the samples are not accidentally contaminated upon entering the Earth’s atmosphere and are delivered in capsules sealed to the surface.

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