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Cellular membrane Design cells / iStock
VIDoctor Rivilla and his colleagues at the Spanish Center for Astrobiology in Madrid made an astonishing detection. The team spotted a vital component of the simplest phospholipid in space. If you don’t know, phospholipids are molecules that make up the membranes of all cells on Earth. In a preprint that has not been peer reviewed, the team explains their discovery of the phospholipid component, known as ethanolamine, and notes that this finding indicates that all precursors of life could come from space.
Science has yet to provide full disclosure on the origin of life, but there are a few things we do know. We know that life on Earth began around 4.5 billion years ago and involved countless molecular components. One theory explains that these components were available on Earth because the planet was seeded from space with the building blocks necessary for life – this space is filled with gas and dust that contain all organic molecules necessary for life.
Astronomers have observed and recorded these building blocks, which include amino acids, the precursors of proteins, and molecules capable of storing information in the form of DNA. But, there is another component essential to life: molecules that can form membranes capable of encapsulating and protecting molecules of life in compartments called protocells. Phospholipids have never been observed in space. Until the discovery of Rivilla and his team.
The origin of life on earth and on other planets
The group analyzed light from an interstellar cloud of gas and dust called Sagittarius B2, just 390 light years from the center of the Milky Way. Ethanolamine has the chemical formula NH2CH2CH2OH. The team simulated the spectrum that this molecule is expected to produce at the cold temperatures assumed to exist in the cloud. They then searched and found clear evidence of this spectrum in the light that had passed through the cloud. “This has important implications not only for theories of the origin of life on Earth, but also on other habitable planets and satellites anywhere in the Universe,” the team said.
Previously, astronomers had found ethanolamine in meteorites. Researchers still don’t know how it got there, with some claiming it only formed through a bizarre set of reactions on a parent asteroid.
However, according to the latest finding, ethanolamine is much more prevalent.
The secret never ends
On Earth, ethanolamine forms the hydrophilic head of phospholipid molecules that self-assemble into cell membranes. Rivilla and her colleagues told Astronomy Magazine that her discovery in interstellar clouds suggests that “ethanolamine could have been transferred from the protosolar nebula to planetesimals and minor bodies in the solar system, and then to our planet.” This, in turn, could have led to the formation of cells in the prebiotic soup from which our earliest ancestors emerged.
Another radical idea is that ethanolamine could allow the formation of protocells in the interstellar medium itself. The interstellar medium is rich in other prebiotic components, such as water and amino acids. The result would then be ready-made crucibles of prebiotic goop ready to sow the Earth or any passing body.
While none of these elements answer the question of how life began on Earth, these works indicate that there is no longer a mystery as to the origin of the building blocks of life. “These results indicate that ethanolamine forms efficiently in space and, if delivered to early Earth, it could have contributed to the assembly and early evolution of early membranes,” said Rivilla et al. ‘team. However, what happened next is still shrouded in secrecy.
