Jupiter is the largest, at 318 Earth masses, whereas Mercury is the smallest, at 0.055 Earth masses.
Mercury is the smallest and innermost planet in the Solar System.
Mercury is a rocky body like Earth. It is the smallest planet in the Solar System, with an equatorial radius of 2,439.7 kilometres (1,516.0 mi).
Mercury's surface is similar in appearance to that of the Moon.
Vulcan is a small hypothetical planet that was proposed to exist in an orbit between Mercury and the Sun.
