Scientists at Yale University have discovered a nearby super-Earth that is a “diamond planet” — a planet that has a mantle made of graphite and diamond.

The planet, called 55 Cancri e, is just 40 light years from Earth and orbits the binary star 55 Cancri, which is located in the constellation of Cancer. When the planet was first observed last year, it was originally thought to be a water planet, similar to Earth, but new information has allowed the scientists to infer that the planet is much more likely to be a diamond planet.

55 Cancri e (which desperately needs a nickname) is referred to as a super-Earth because it is larger than Earth, but not as large as the Solar System’s gas giants. That’s where 55 Cancri e’s similarities to Earth end, though. 55 Cancri e has twice the radius of Earth, eight times the mass — and because it’s the innermost planet in the 55 Cancri system, the planet has a surface temperature of 3,900 degrees Fahrenheit (2,150 Celsius), and its year lasts just 18 hours (as opposed to Earth’s 365 days).

But why is 55 Cancri e made out of diamonds? Because the star system itself is primarily made up of carbon, iron, and silicon — and over millions of years of pressure and heat, the planet’s carbon mantle has slowly turned into diamond. The Yale scientists estimate that as much as one third of 55 Cancri e’s mass is made up of diamond — the same as three Earth masses, or roughly 18×1024kg. This is a few trillion times more diamond than has ever been mined on Earth.

Suffice it to say, the identification of just a single diamond-rich planet is massive news. In recent years we have identified hundreds of rocky, Earth-like planets — and until now, we had assumed they had similar make-ups. It is now fairly safe to assume that there are millions of diamond planets in the universe. There could be other planets out there with different chemistries, too — water planets, gold planets, uranium planets — and each are likely to have very different atmospheres, biologies, and geological/tectonic characteristics.

The idea of mining other planets and asteroids for valuable resources doesn’t seem quite so crazy now, eh?

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