The true nature of this planet is a mystery. Inclination of the axis - the number of degrees that the rotational axis of an object is inclined from a line that is perpendicular to the plane of its orbit around another object. These two planets have phases like the Earth's Moon because they revolve inside the orbit of the Earth and are sometimes between the Sun and the Earth and sometimes behind the Sun. Retrograde motion of planets beyond the Earth - The apparent backward motion of the planets as the Earth passes by them on its closer and interior orbit. About the size of the Earth's moon.
All atmosphere has escaped, so there are many craters.
Revolution occurs in 88 days. Period of revolution is 365.26 solar days. Known as the water planet because of its vast oceans. Four of Jupiter's moons are large enough to be seen with binoculars. The planet with the most visible rings.