Did Key Building Blocks For Life Come From Deep Space

2018-10-01 10:42:23

Comet 67P/Churyumov-Gerasimenko [Credit ESA/Rosetta/NAVCAM]

Comet 67P/Churyumov-Gerasimenko [Credit ESA/Rosetta/NAVCAM]

All living beings need cells and energy to replicate. Without these fundamental building blocks, living organisms on Earth would not be able to reproduce and would simply not exist.

According to the study, phosphates and diphosphoric acid are two major elements that are essential for these building blocks in molecular biology. They are the main constituents of chromosomes, the carriers of genetic information in which DNA is found. Together with phospholipids in cell membranes and adenosine triphosphate, which function as energy carriers in cells, they form self-replicating material present in all living organisms.

In an ultra-high vacuum chamber cooled down to 5 K (-450°F) in the Laboratory researchers replicated interstellar icy grains coated with carbon dioxide and water, which are ubiquitous in cold molecular clouds, and phosphine. When exposed to ionizing radiation in the form of high-energy electrons to simulate the cosmic rays in space, multiple phosphorus oxoacids like phosphoric acid and diphosphoric acid were synthesized via non-equilibrium reactions.

The phosphorus oxoacids detected in the experiments by combination of sophisticated analytics involving lasers, coupled to mass spectrometers along with gas chromatographs, might have also been formed within the ices of comets such as 67P/Churyumov-Gerasimenko, which contains a phosphorus source believed to derive from phosphine.

Since comets contain at least partially the remnants of the material of the protoplanetary disk that formed our solar system, these compounds might be traced back to the interstellar medium wherever sufficient phosphine in interstellar ices is available.

Upon delivery to Earth by meteorites or comets, these phosphorus oxoacids might have been available for Earth's prebiotic phosphorus chemistry. Hence an understanding of the facile synthesis of these oxoacids is essential to untangle the origin of water-soluble prebiotic phosphorus compounds and how they might have been incorporated into organisms not only on Earth, but potentially in our universe as well.