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Paul M. Sutter is an astrophysicist at SUNY Stony Brook and the Flatiron Institute, host of Ask a Spaceman and Space radio, and author of How to die in space. He contributed this article to Space.com Expert voices: opinions and ideas.
Where are the ingredients for life on earth comes from? A team of astronomers has found a crucial new link: the observation of essential “prebiotic” molecules around a star still forming.
One day, these molecules can end up on a planet and become the necessary items for life.
Related: 10 exoplanets that could harbor extraterrestrial life
Intensify
One of the many factors that distinguish life from non-life is the ability of life to use a variety of molecular tools to store, transport, and release energy. The cells of your body are a true chemical civilization in miniature, with DNA and the knock-calling RNA, the proteins that work back and forth to make the growl and the lipid networks to keep everything intact.
All of these complex molecules are based on a few precursors, called prebiotics. We don’t know exactly how complex life appeared on Earth (or could emerge elsewhere in universe), but it seems obvious that if you want to go from non-living to definitely alive, you have to go through some complexity steps involving these precursor molecules.
For example, methyl isocyanate (CH3NCO) and glycolonitrile (HOCH2CN) are isomers of each other – they have the same basic elements, but these elements are arranged differently in space. They are both individually extremely dangerous to human health. Methyl isocyanate is caustic and irritant, and glycolonitrile quickly breaks down to formaldehyde and hydrogen cyanide.
Although these two molecules are not so friendly on their own, they play a key role in the stages leading to life. They are involved in the formation of peptide structures (peptides eventually stick together to form proteins) and adenine, which is one of the four bases in the genetic code of our DNA.
Look at the light
Why am I talking so much about methyl isocyanate and glycolonitrile? Because astronomers just found evidence for the presence of these two prebiotic molecules in deep space, research finds article recently published in the pre-print journal arXiv, which has been accepted for publication in the journal Astronomy and Astrophysics.
Astronomers found these pre-creatures in Serpens SMM1-a and IRAS 16293B, the astronomical designations of two protostars.
Protostars are, as the name suggests, not quite stars yet. They are still forming, collapsing from clouds of gas and dust, but have not reached the densities and temperatures necessary to trigger nuclear fusion. Observing protostars is essential for understanding how life evolves in the universe, as it is from this proto-soup that the planets end up emerging and, to a large extent, they are born with what they get from the system. early proto-stellate.
So if we want to research the origins of life, we have to look inside stellar wombs like these.
To identify the molecules, astronomers used a technique called spectroscopy. The protostars are at this stage only clusters of dust denser than the average. They aren’t incredibly hot and bright, which makes it difficult to see them, unless you have the world’s most powerful radio telescope at your back.
What the astronomers did.
Using the Atacama Large Millimeter / Sub-millimeter Array (ALMA) in Chile, astronomers have carefully studied the light coming from protostars. Buried in that light was the subtle hint of all manner of elements and molecules, each giving off its own fingerprint of wavelengths. By matching fingerprints to known emissions of various elements, astronomers were able to find the prebiotics.
So fantastic: more ingredients for life were found in a young and still developing system. This means that if these systems develop planets, and those planets have the right conditions, then life has at least two of the essential tools it needs.
So how did prebiotics get there?
Related: Amazing photos of the ALMA radio telescope array
In the mix
Methyl isocyanate and glycolonitrile don’t just float around the universe at random, hoping for a chance at being part of a star system. Investigations of interstellar gas clouds did not find these prebiotic molecules, which means that the protostar systems must have somehow baked these molecules on their own.
Astronomers believe that in the case of the SMM1-a, it experienced a period of relative calm in the recent past, when icy dust could encircle the star that would soon become non-melting – but also not blocking. This allowed chemical reactions to occur, as various elements exchanged in interesting molecular combinations.
We do not yet know whether the processes that led to the formation of these prebiotics around protostars are common across the galaxy or specific to these systems. Further studies will help pinpoint this answer, which is just one of many answers needed to understand how common life is in the universe.
Read more: “The prebiotic molecular inventory of Serpens SMM1 I. An investigation of the isomers CH3NCO and HOCH2CN“
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