Rocks from space

via commons

Our solar system is crossed by a lot of rocks like comets and meteorites. Following the panspermia hypotesis, these cosmic objects could be at the origin of life-as-we-know. And two paper recently published seems confirmed it.
Comet 21P/Giacomini-Zinner belongs to the cometary family of Jupiter, with an orbital period of about 6.6 years. Discovered on the 20th decembre 1900 by Michel Giacobini, it could be the origin of the Draconids meteor shower. In July 2005 a japanese team of astronomers decided to observe 21P using the Comics instrument (Cooled Mid-Infrared Camera and Spectrometer) mounted on the Subaru telescope. Now they have concluded the examination of data, detecting an unidentified infrared emission, as well as thermal emissions generated by the silicate and carbon grains, which is probably due to complex organic molecules.

Ootsubo, T., Kawakita, H., Shinnaka, Y., Watanabe, J. I., & Honda, M. (2020). Unidentified infrared emission features in mid-infrared spectrum of comet 21P/Giacobini-Zinner. Icarus, 338, 113450. doi:10.1016/j.icarus.2019.113450

In the meanwhile another japanese team studied a couple of meteorites falled on Earth: Nwa 801, recovered in 2001 in Morocco, and Murchison, fallen in Australia in 1969.
Also in these cases the results are very interesting: the team, indeed, find some sugars essential for life: ribose and other biotic sugars, including arabinose and xylose. In particular the ribose is an essential component of ribonucleic acid, commonly known as Rna, a molecule of fundamental importance for life. This nucleic acid, in fact, performs the delicate function of copying the genetic instructions contained in the DNA molecule (deoxyribonucleic acid) to deliver them to the molecular factories inside the cell, called ribosomes, where proteins are synthesized.

Furukawa, Y., Chikaraishi, Y., Ohkouchi, N., Ogawa, N. O., Glavin, D. P., Dworkin, J. P., ... & Nakamura, T. (2019). Extraterrestrial ribose and other sugars in primitive meteorites. Proceedings of the National Academy of Sciences, 116(49), 24440-24445. doi:10.1073/pnas.1907169116