Out amongst the stars, there may be carbon rich planets made of diamonds

Researchers at Arizona State University (ASU) and the University of Chicago have determined in a study published in The Planetary Science Journal that some planets may shine bright like diamonds because they are, in fact, diamonds. 

As the search for life amongst the stars expands outward with our ever-improving ability to observe deep space and faraway star systems, scientists are increasingly "able to piece together what [distant] planets look like, what they are made of, and if they could be habitable or even inhabited," according to a press release from EurekAlert!

Given the right circumstances in these distant star systems, there could be exoplanets rich in life or planets rich in carbon and made of diamonds and silica. 

Within solar systems, planets and their host stars form from the same cloud of gas and dust, which means their relative compositions are very similar. Our sun happens to have a "low carbon to oxygen ratio," so Earth is home to a tiny fraction of diamonds (about 0.001%), according to the press release. 

However, stars with a high carbon to oxygen ratio could potentially host carbon-rich exoplanets. Given the presence of water (an abundant resource in the universe), according to lead author Harrison Allen-Sutter and co-authors Emily Garhart, Kurt Leinenweber, W. et al., alien exoplanets could have a diamond-rich composition by "[converting] diamond and silicate." 

The researchers tested their theory by putting silicon carbide in water and compressing it between two diamonds in a high pressure diamond-anvil cell – a device used to create extremely high pressures, and heated it up with lasers. This process "[mimicked] the interior of carbide exoplanets" and turned the silicon carbide into silica and diamonds.  

Out among the stars, definitive evidence for life beyond the confines of our pale blue dot remains elusive. 

Diamond planets, however, would not add to the tree of life in the universe. They would be completely hostile to life, lacking the volcanic activity indicative of habitable planets for one. Nor would they have an atmosphere, which is something all living things we know of need to survive. "These exoplanets are unlike anything in our solar system," Allen-Sutter said in the press release. "Regardless of habitability, this is one additional step in helping us understand and characterize our ever-increasing and improving observations of exoplanets."