Diamond worlds ‘unlike anything in our Solar System’ are entirely possible. We just haven’t found them yet

As an extra incentive to get humanity’s colonization capabilities up to scratch, researchers have revealed that not only are worlds made mostly of diamonds possible, they are in fact quite probable (not to mention profitable).

With private space companies slowly but surely gaining a foothold in low-Earth orbit, amid plans to take humans to the moon and Mars in the next decade, the potential plunder available farther afield looks increasingly promising. 

Researchers at Arizona State University have recently published a paper in which they detail the circumstances necessary for these so-called “diamond world” exoplanets to arise, as well as a proof-of-concept experiment. 

"These exoplanets are unlike anything in our Solar System," says geophysicist Harrison Allen-Sutter of Arizona State University's School of Earth and Space Exploration.

Their research is based on the idea that not all stars are created equal, and the chemical composition of the planets in a given star system are largely dictated by that of their star. 

According to current estimates, between 12 and 17 percent of planetary systems might inhabit the space around carbon-rich stars, a promising precursor for diamond worlds.  

Scientists and researchers have already confirmed the existence of carbide planets, made primarily of carbon and a handful of other elements, but they have to encounter the hypothesized silicon carbide (aka 'diamond') planets with just a hint of water to oxidize and convert the carbide to its constituent silicon and carbon. 

Allen-Sutter and his team are making the case that, with enough heat, pressure and a dash of water, these silicon carbide worlds could be covered in diamonds. To prove their point, the researchers used a diamond anvil cell, subjecting test materials to extraordinarily high pressures. 

They immersed samples of silicon carbide in water and then squeezed the hell out of them at a pressure of around 50 gigapascal, or 500,000 times the Earth's atmospheric pressure at sea level. Adding insult to injury, the team then blasted the squeezed samples with lasers to heat them up. 

They conducted 18 runs of this experiment and, as predicted, the silicon carbide samples broke down and converted into silica and diamonds. So the theorized ‘diamond worlds’ are entirely feasible, we just need to find them.

For those tempted to search the cosmos for these diamond worlds, the sweet spot would be planets with a temperature of 2,500 Kelvin (2,226 degrees Celsius, 4040 degrees, Fahrenheit), a high-pressure atmosphere and the presence of water on top of a mostly silicon carbide rock, a somewhat tall order, but worth it to find a diamond in the galactic rough. 

The researchers warn budding interplanetary treasure-hunters that these worlds would not be remotely hospitable for miners, as their atmospheres would be toxic to all life as we know it. So interstellar Indiana Joneses would need some pretty beefy machinery to extract the riches from these extraordinary planets. 

In the meantime, upcoming missions like the James Webb Space Telescope and the Nancy Grace Roman Space Telescope will help identify both these diamond worlds as well as a plethora of other interesting planets and potential treasure troves of alien life.

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