Saturn is the second largest (after Jupiter) of our solar system's planets. One of the giant Jovian Planets that roam the outer solar system, it is 95 times heavier
than the Earth, and nearly ten times its size. It takes 29.5 years to orbit the Sun.
Saturn is encircled by a beautiful system of very thin rings, made up of icy debris that orbits at the equator. The visible light image shows the rings,
as well as bands of clouds in Saturn's atmosphere. The observed light is sunlight that gets reflected back to us by the planet. By contrast, the radio image
is dominated by Saturn's own heat glow. In X-rays it is possible to detect the planet, but little detail is evident.
Many stars in the Universe host a system of planets. Astronomers have detected Jovian planets around many nearby stars. However, the detection methods
have been indirect and images of these planets do not exist. Terrestrial planets have thus far proven too small and faint to detect around other stars. In our
solar system, Mercury, Venus, Earth and Mars are the rocky Terrestrial Planets and orbit closest to the Sun. Further away, the Jovian Planets (Jupiter, Saturn,
Uranus and Neptune) are mostly made of gas. They have no solid surface. All planets have been explored with unmanned spacecraft. Voyager 2 visited all four Jovian
planets, taking 12 years after its launch in 1977 to reach Neptune. Pluto was long considered the ninth planet but was recently reclassified as a
"dwarf planet", a class of objects in the outer solar system made mostly of ices.
90 Megawatts of X-ray power (colored white) comes from Saturn's equator. These are mostly reflected X-rays from the Sun.