Research Suggests Meteorites 'Brought' Phosphorous to Earth

Meteorites had crashed into the earth a billion years ago, and along with it was the essential nutrient vital to terrestrial life. According to scientists, meteorites had brought phosphorous into earth, which is vital to the evolution of life on the planet.

"In terms of mass, phosphorus is the fifth most important biologic element, after carbon, hydrogen, oxygen, and nitrogen," explained Matthew A. Pasek of the University of Arizona's planetary sciences department and Lunar and Planetary Laboratory. "But where terrestrial life got its phosphorus has been a mystery."

Compared to hydrogen, oxygen, nitrogen, and carbon, phosphorous is quite rare in the environment, which is why understanding the behavior of it would give clues to the origin of life on earth. The nutrient is the backbone of DNA and RNA, and it is a vital component of metabolism. In addition, phosphorous makes up the cell walls and bones of vertebrates.

Scientists have gone through several tests just to find where and how phosphorous had originated from. This is why the idea of testing meteorites as the source of phosphorous came to light. Pasek worked with another professor of planetary sciences, Dante Lauretta, to experiment on this idea.

"I think meteorites were critical for the evolution of life because of some of the minerals, especially the P2-07 compound, which is used in ATP, in photosynthesis, in forming new phosphate bonds with organics (carbon-containing compounds), and in a variety of other biochemical processes. Meteorites have several different minerals that contain phosphorus. The most important one, which we've worked with most recently, is iron-nickel phosphide, known as schreibersite," explained Pasek.

The metallic compound, schreibersite, is extremely rare on the planet. However, it is abundant in meteorites, particularly iron meteorites. Another principle on the formation of phosphorous is that the nutrient could have bonded with oxygen while in space. This would have begun the construction of life's molecules, even before it had reached earth.