The closest planet to the Sun has remained an enigma for scientists. New research suggests parts of this planet that once used to be super-Mercury may have arrived on Earth during the early days of the Solar System.The closest planet to the Sun has remained an enigma for scientists. New research suggests parts of this planet that once used to be super-Mercury may have arrived on Earth during the early days of the Solar System. Broken parts of Mercury may be hiding on Earth - SCIENCE News