The nearness of Mercury to the massive gravity influence of the Sun is the likely reason that no natural satellites are present, although it is possible that one or more may have existed in the past. Mercury does not have any moons. It was once believed that a moon might exist, based on radiation levels. However. it was later discovered to be the star 31 Crateris. The nearness of Mercury to the massive gravity influence of the Sun is the likely reason that no natural satellites are present, although it is possible that one or more may have existed in the past. Mercury does not have any moons.