Astronomers have discovered a prebiotic molecule in molecular clouds in space, a finding that could be important in our understanding of how life evolved on Earth. The molecule, ethanolamine (NH2CH2CH2OH), is known as a prebiotic compound that precedes the advent of life on Earth and possibly plays a role in it.
In living organisms, such a molecule is part of the cell membrane, the barrier between different cells. Ethanolamine has previously been discovered in meteorites, and researchers suspected that it was something in the meteorites that must have facilitated the formation of the molecule. The new research, published in Proceedings of the National Academy of Sciences, changes this picture.
The team observed a molecular cloud called G+0.693–0.027 located near the center of the Milky Way. This is one of the most chemically rich clouds in the galaxy. Using a radio telescope, they spotted the faint emissions of ethanolamine in the cloud in a surprising abundance.
“These results suggest that ethanolamine forms efficiently in interstellar space in molecular clouds where new stars and planetary systems form,” lead author Víctor M. Rivilla from the Centro de Astrobiología in Madrid, said in a statement.
The observations suggest that the abundance of this molecule in interstellar space is similar to what has been found in meteorites. This led the team to conclude that it formed between the stars and was then later incorporated into space rocks as the Solar System formed.
These rocks eventually rained down on Earth bringing the ethanolamine with them. According to the team's experiments, this molecule could have eventually produced phospholipids, the larger molecules that make cell membranes.
“The availability of ethanolamine on the early Earth, together with fatty acids or alcohols, may have contributed to the assembly and early evolution of primitive cell membranes. This has important implications not only for the study of the origin of life on Earth but also on other habitable planets and satellites anywhere in the Universe,” co-author Carlos Briones said.
The observations were conducted using the IRAM 30-meter and Yebes 40-meter radiotelescopes in Spain. There are, however, bigger and more sophisticated instruments out there to look for such molecules, so the researchers believe that we may well soon better understand where some crucial components of life come from.
“Thanks to the improved sensitivity of the current and next generation of radio telescopes, we will be able to detect interstellar molecules with increasing complexity that are direct precursors of the three basic components of life: lipids which form the membranes, RNA and DNA nucleotides which contain the genetic information, and also proteins that are responsible for the metabolic activity, says Víctor M. Rivilla.
“Are these prebiotic seeds distributed across the whole Galaxy, and even in other galaxies? We will know relatively soon."