Jupiter, rotating during a Jovian day. Jupiter's rotation on its axis with respect to the stars (the sidereal period) takes 9 hours, 55 minutes and 30 seconds. Mars, named after the Roman king of the gods, is the fifth planet from the Sun. It is the largest planet in the solar system, with a diameter of 142, 984 kilometres. It is a gas giant that is mostly hydrogen and helium. Swirling clouds and storm systems are visible in its atmosphere, including the Great Red Spot (lower left at start and end of clip).