We have long pondered how life came to be on our lovely planet and what we know so far is that all biological molecules on Earth consist of six chemical elements: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur (CHNOPS). In the past, we have found most of these elements in comets.
Four of these (carbon, hydrogen, nitrogen, oxygen) are the main ingredients of carbonaceous asteroids while the fifth (sulfur) was discovered in a chemical analysis of comet 67P/Churyumov-Gerasimenko. It is in this same comet that researchers have now found the sixth and final missing element of life: phosphorus.
An important first
"This is the first time that life-necessary CHNOPS elements are found in solid cometary matter. Carbon, hydrogen, nitrogen, oxygen and sulphur were reported in previous studies by the Cometary Secondary Ion Mass Analyzer (COSIMA) team from e.g. organic molecules," stated a press release from the University of Turku regarding the find.
"The discovered phosphorus, or P, is the last one of the CHNOPS elements. The discovery of P indicates cometary delivery as a potential source of these elements to the young Earth."
The find may finally reveal that it is indeed comets that brought life to the Earth billions of years ago.
COSIMA is an instrument on-board the European Space Agency’s Rosetta spacecraft. The spacecraft tracked the comet between September 2014 and September 2016 and the dust particles that led to the phosphorus find were collected directly in the vicinity of the comet.
All of this process was impressively enough controlled from Earth on a comet that takes 6.5 years to orbit the Sun. The target plates were photographed remotely and the particles were identified from the resulting images. It should be noted that fluorine was also detected although its importance and role have yet to be identified.