Molten sphere could give clues to planetary mass Researchers at the Massachusetts Institute of Technology have discovered a new, Earth-sized exoplanet for which orbiting its star is literally all in a day's work.The newly discovered planet, dubbed Kepler 78b, completes one full revolution around its star in just 8.5 hours – fast enough that by the time you clock in at the office and clock out again, another solar year will have passed for Kepler 78b. To achieve this rapid orbital period, the planet revolves around its star at a distance 40 times closer than Mercury is to our sun.As...