Meteorites Brought Phosphorous to Earth About 3.5 Billion Years Ago

Researchers have found that phosphorous arrived on Earth via meteorites more than 3.5 billion years ago.

The latest study was conducted by researchers from University of South Florida and colleagues, who found that phosphorous in rocks of early Archean limestone was quite abundant. Hadean and Archean eons are among the four eons when the Earth was constantly bombarded with meteorites. These meteorites could have got the large amounts of phosphorous on Earth and helped sustain life.

Researchers said that the meteorites delivered many other minerals on Earth, and these minerals released phosphorous in the oceans. This process also explains why we don't see new life forms emerging today.

Early life was RNA-based and previous studies couldn't explain how these life forms synthesized phosphorous, which presently is rather unreactive.

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

According to Pasek, the environmental conditions that kick-started life don't exist anymore.

"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," he added.

For the study, researchers examined core samples from Australia, Zimbabwe, West Virginia, Wyoming and in Avon Park, Florida. Of the many samples analyzed, only the Coonterunah carbonate samples from the early Archean of Australia had phosphite.

There are other sources of phosphorous such as hydro-geothermal vents and anaerobic bacteria, but researchers say that none of these sources could release massive amounts of phosphorus. However, the research team added that more research would be required to determine the amount of phosphorous from each source.

The study article is published in the journal Proceedings of the National Academies of Sciences.