The planet Jupiter, Voyager 1979.
© National Aeronautics & Space Administration / Science & Society
Photographed by one of the Voyager spacecraft. The largest planet in the solar system, Jupiter is a type of planet known as a gas giant, with an atmosphere composed mainly of hydrogen and helium. The atmosphere contains distinctive banded cloud formations, and a number of large storms, the most famous of which, the Great Red Spot, is larger than the Earth and has been in existence for at least 300 years. NASA's two Voyager spacecraft were launched in 1977 to explore the planets in the outer solar system. Voyager 1 flew past Jupiter at 278,000 kilometres in March 1979 before flying on to Saturn. Voyager 2 reached Jupiter in 1979 before visiting Saturn in 1981, Uranus (1986) and Neptune (1989).