Life on Earth Kickstarted by Reactive Phosphorous From Meteorites 3.5 Billion Years Ago

When and how life began forming on Earth is still a mystery, but scientists have no uncovered another piece of the puzzle. According to a new study, reactive phosphorous, which is a key component to the formation of life, was carried to Earth by meteorites around 3.5 billion years ago.

Scientists generally believe that our modern biological makeup of DNA, RNA, and proteins stemmed from an "RNA world," as the team put it in their study published in the Proceedings of the National Academy of Sciences. However, it has been difficult to reproduce the formation of RNA phosphates in early Earth conditions without a reactive form of phosphorous.

"Meteorite phosphorus may have been a fuel that provided the energy and phosphorus necessary for the onset of life," said Matthew Pasek, an assistant professor of geology at the University of South Florida. "If this meteoritic phosphorus is added to simple organic compounds, it can generate phosphorus biomolecules identical to those seen in life today."

The findings highlight the environmental differences between Earth, which began forming 4.5 billion years ago, in its early stages and present-day Earth.

"The present research shows that this is indeed the case: Phosphorus chemistry on the early Earth was substantially different billions of years ago than it is today," Pasek explained.

While the formation of life from RNA has been previously proven, scientists have been puzzled as to how phosphorous in a reactive, life-building form could have arrived, given that it is so hard to find today. Meteorites, it seems, brought over reactive phosphorous in the form of iron-nickel phosphide mineral schreibersite, which releases soluble phosphite in water. Phosphite is believed to be the salt incorporated into prebiotic molecules, and one of the key drivers in creating life as we know it today.

The team of researchers acknowledged that phosphite could have also arose from other natural phenomena, such as hydrothermal vents.