Arthur C. Clarke, the late science-fiction writer most famous
for “2001: A Space Odyssey,” let his mind wander all over the
universe. In a sequel, “2010: Odyssey Two,” one of his
extraterrestrial characters discovered that “the core of
Jupiter, forever beyond human reach, was a diamond as big as the
Earth.” Now, a team of researchers led by Nikku Madhusudhan of
Yale University say they may have found the real thing – a so-
called super-Earth, orbiting a star 40 light-years away in the
constellation Cancer the crab. From its orbit and the size of
its host star, they can calculate its size and mass – its
diameter is double that of Earth – and have concluded that it is
unusually dense. How dense? To borrow a line from Clarke, “De
Beers shareholders, please note.” “The surface of this planet is
likely covered in graphite and diamond rather than water and
granite,” said Madhusudhan in a statement from Yale. “This is
our first glimpse of a rocky world with a fundamentally
different chemistry from Earth.” The planet