Astronomers Trace Interstellar History of Essential Element of Life

(CN) – Astronomers in Europe have mapped out the cosmic history of one of life’s most essential elements, phosphorus, tracing the mineral’s interstellar journey from the star-forming regions of space directly to DNA of life on Earth.

The second most abundant mineral in the body, phosphorus is present in every cell of the human body. It is also an essential mineral found in food and key to healthy plant life.

Four antennas of the Atacama Large Millimeter/submillimeter Array star-gazing project point up at the night sky over the Chajnantor plateau in the Atacama Desert in Chile. (ESO Photo Ambassador José Francisco Salgado)

For years, scientists sought to unlock the story of how the element arrived on Earth. Now, a team of astronomers utilizing highly sensitive star-gazing instruments have charted out the element’s journey for the first time, according to a study published Wednesday in Monthly Notices of the Royal Astronomical Society.

New evidence collected by the Atacama Large Millimeter/Submillimeter Array (ALMA) project in Chile and the European Space Agency’s ROSINA tool aboard its Rosetta probe reveals how molecules containing phosphorus grow and how they get transported across space by comets.

Víctor Rivilla, the study’s lead author, said in a statement that many questions about essential elements remain unsolved. But the findings show the critical role that phosphorus monoxide has in generating life.

“Life appeared on Earth about 4 billion years ago, but we still do not know the processes that made it possible,” said Rivilla, who is with the Arcetri Astrophysical Observatory in Italy, in a statement accompanying the study. “The combination of the ALMA and ROSINA data has revealed a sort of chemical thread during the whole process of star formation, in which phosphorus monoxide plays the dominant role.”

Rivilla and his colleagues set their sights on massive cloud-like regions of gas and dust in the cosmos to better understand how stars and planetary systems form.

Using ALMA, astronomers found their clue by examining star-forming region AFGL 5142 and pinpointing where phosphorus-bearing molecules, like phosphorus monoxide, are created.

Researchers found that phosphorus-bearing molecules are created within the walls of giant cavities in interstellar clouds where stars form, according to the study. Shocks and radiation from the infant star’s development contribute to the formation of phosphorus, they found.

Astronomers then turned their sights on the comet 67P/Churyumov-Gerasimenko to understand how icy dust grains around new stars form pebbles and rocks that develop into comets transporting phosphorus monoxide through space.

In the constellation of Auriga, astronomers have pinpointed massive star-forming clouds, top left, that produce the essential life element phosphorus monoxide as well as tracking the 67P comet, bottom left, as it carries phosphorus-bearing molecules along its interstellar journey from the cosmos to Earth. (ALMA / ESO / ESA)

Rosetta orbited the comet for two years as ROSINA – the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis – collected data for the study.

Study author Kathrin Altwegg said in a statement that researchers struggled to identify which molecule carried the phosphorus coming up in their data but got a clue from a fellow astronomer at a conference.

“She said that phosphorus monoxide would be a very likely candidate, so I went back to our data and there it was,” Altwegg said. “As comets most probably delivered large amounts of organic compounds to the Earth, the phosphorus monoxide found in comet 67P may strengthen the link between comets and life on Earth.”

European Southern Observatory astronomer Leonardo Testi credited the interplay between telescopes on Earth and instruments in space for revealing phosphorus monoxide’s chemical thread through the cosmos.

“Understanding our cosmic origins, including how common the chemical conditions favorable for the emergence of life are, is a major topic of modern astrophysics,” said Testi in a statement. “While ESO and ALMA focus on the observations of molecules in distant young planetary systems, the direct exploration of the chemical inventory within our solar system is made possible by ESA missions, like Rosetta.”

Lead author Rivilla did not respond to an emailed request for comment.

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