Saturn is the sixth planet from the Sun and is the second largest in the solar system with an equatorial diameter of 119,300 kilometers (74,130 miles). Much of what is known about the planet is due to the Voyager explorations in
1980-81. Saturn is visibly flattened at the poles, a result of the very fast rotation of the planet on its axis. Its day is 10 hours, 39 minutes long, and it takes 29.5 Earth years to revolve about the Sun. The atmosphere is primarily composed}
of hydrogen with small amounts of helium and methane. Saturn is the only planet less dense than water (about 30
percent less). In the unlikely event that a large enough ocean could be found, Saturn would float in it. Saturn's hazy yellow hue is marked by broad atmospheric banding similar to, but fainter than, that found on Jupiter.
The Sun is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of
the total solar system mass. One hundred and nine Earths would be required to fit across the Sun's disk, and its interior could hold over 1.3 million Earths. The Sun's outer visible layer is called the photosphere and has a temperature of 6,000°C (11,000°F). This layer has a mottled appearance due to the turbulent eruptions of energy at the surface.
Eventually the hydrogen in the centre will all have been converted into helium. The balance between the force of
gravity pulling all the Sun's mass towards its centre, and the force due to the energy in the Sun which pushes matter outwards, will then be upset. The centre will contract and become even hotter while the outer part will expand and become cooler. The Sun will then be brighter, cooler and bigger - a red giant star. Ultimately all sources of energy production will come to an end and the Sun will collapse to become a very small hot object called a white dwarf.