Nothing can be born from diamonds
The diamonds, or rather the carbon which is the constituent, are not the best friends of life. A theoretical model, developed by an international team led by researchers at NASA, indicates that an excess of carbon in stellar systems in formation sequesters oxygen which could give rise to water. To make a habitable planet, in a way similar to the Earth, we need a long list of ingredients and adequate procedures for mixing. Firstly it must be sufficiently compact and reside in temperate districts of its star system, the so-called end area, in order to be able to accommodate liquid water on its surface.
The composition of the rocks from which the planet takes its origin amalgam should not, however, be too rich in carbon; otherwise the planet will only dry up. This is the conclusion that an international research team, led by Torrence Johnson of NASA’s Jet Propulsion Laboratory, has reached; team that has developed a theoretical model for the evolution of planetary based on the carbon-oxygen ratio found in the Sun. Like other stars, including our own, inherited a set of chemical elements from the Big Bang and previous generations of stars, a soup consisting mainly of hydrogen and helium and then other ingredients such as nitrogen, silicon, carbon and oxygen in different proportions.
The Sun is a star relatively poor in carbon and, consequently, the Earth is mainly composed of silicate rocks. On the other hand, it is foreseeable that around stars rich in carbon, there are abundant planets of that element in its various forms, including diamond. The model developed by Johnson and colleagues allows calculating precisely how much water is trapped in the form of ice at the beginning of the history of the solar system, billions of years ago, before people started to form the Earth. Ice and afterwards would have fed the water reserves of the Earth by the impact of comets and asteroids, although this theory is still under discussion. When the researchers applied the model to the carbon -rich stars, the water is simply missing in their calculations.
“The fundamental building blocks at the base of our oceans are asteroids and icy comets,” explained Johnson. “Following their tracks, we find that planets around stars rich in carbon become dry.” The reason is obvious: the excess carbon in the star systems in evolution takes possession of the available oxygen to form carbon monoxide, thus inhibiting the formation of water. “It’s ironic that the carbon , the main chemical element in life, becoming too abundant takes away the oxygen that could become water, the solvent that is so essential for life as we know it ,” said Jonathan Lunine of Cornell University and collaborator of research.
The results of this research will help us to select the exoplanets in the habitable zone presenting more prospective in finding traces of life. “Not all the rocky planets were formed in the same manner,” concludes Lunine. “The so-called diamond planets the size of Earth, if they exist, they would appear utterly alien: no world’s oceans and lifeless.”