RT @coreyspowell: Galileo’s discovery of the moons of Jupiter, jotted at the bottom of a discarded letter, 1610. bit.ly/1IQNZ7O http://t.co/b69c2hJOU3
RT @coreyspowell: Galileo’s discovery of the moons of Jupiter, jotted at the bottom of a discarded letter, 1610. bit.ly/1IQNZ7O http://t.co/b69c2hJOU3