In roman god terms the difference between mercury and jupiter
is that
mercury is the Roman god associated with speed, sometimes used as a messenger. He wore winged sandals. Mercury corresponded to the Greek god Hermes while
jupiter is the King of the Gods, also called Jove. Equivalent to the Greek Zeus, Jupiter was one of the children of Saturn.
In astronomy terms the difference between mercury and jupiter
is that
mercury is the planet in the solar system with the closest orbit to the Sun, named after the god; represented by ☿ while
jupiter is the fifth and by far the largest planet in the Solar System, a gas giant, represented by the symbol ♃ in astronomy. Jupiter is known for its Great Red Spot and many moons including the Galilean moons.
As a noun mercury
is a metal.