The rocky planet, called ‘55 Cancri e’, orbits a sun-like star in the constellation of Cancer and is moving so fast that a year there lasts a mere 18 hours.u00a0Discovered by a US-Franco research team, its radius is twice that of Earth’s but it is much more dense with a mass eight times greater. It is also incredibly hot.

“The surface of this planet is likely covered in graphite and diamond rather than water and granite,” said Nikku Madhusudhan, the Yale researcher whose findings are due to be published.