Questions About Saturn
- Saturn is the sixth planet in the Solar system and, when seen through a telescope, by far the most beautiful.
- The bright globe of Saturn is surrounded by rings which may be composed of ice. Three of these rings are visible from the Earth using a telescope. Photographs sent back from the US Voyager spacecraft in the 1980s were able to identify further narrower rings “ringlets” in between the three main rings. The main rings are labelled A, B and C, with A the outermost ring. Recently more rings have been found.
Figure 1: Photograph of Saturn taken from Voyager spacecraft.
- Saturn is the last planet that can be seen without using a telescope or binoculars and the planet was known in the ancient world before telescopes were invented. The rings, however, can only be seen using a telescope.
- The rings were first seen by Galileo in 1610 through a telescope.
- The largest of the moons, Titan, is the 2nd largest in the Solar system, after Jupiter’s moon, Ganymede. Titan is larger than the Earth and is the only moon in the Solar system which is known to have an atmosphere. The atmosphere consists of nitrogen and methane. Titans were Jupiter’s giant sons.
Figure 2: Photograph from Pioneer spacecraft of Saturn, showing the moon Titan above the planet to the left.
- Saturn itself is named, like all the planets, after a Roman God. Saturn was a rather mysterious God but it is believed that he was the God of sowing seed and of the harvest.
- Its mass is 95 times that of the Earth and it has a diameter of 75,098 miles, or 142,750 kilometres.
- Saturn is 886 million miles, or 1426 million kilometres, from the Sun.
- Distances from the Sun are measured in Astronomical Units (AU). The Earth is the standard unit, and is one AU from the Sun, so an AU equals 150 million kilometres (93 million miles), the distance of the Earth from the Sun. Saturn is 9.5 AU from the Sun.
Figure 3 shows the huge distances of Jupiter and Saturn from the Sun.
- Saturn takes 29½ years to make one complete orbit of the Sun. The Earth takes one year.
- Like Jupiter, however, Saturn spins much faster on its axis than the Earth. The Earth completes one rotation (turning) on its axis in 24 hours, turning away from the Sun and back again to give us night and day. Saturn, although so much bigger, completes a full rotation in just over 10 hours.
- This rapid spinning leads to hurricane-like storms far, far stronger than anything that is seen on the Earth. There is a constant whirlwind storm at Saturn’s south pole which can be observed with the strongest telescopes.
- The four largest outer planets, Jupiter, Saturn, Uranus and Neptune, are known as the “gas giants” since it is thought they are entirely made up of dense layers of gas. Saturn is a great ball of hydrogen and helium
- Saturn’s axis is tilted and as the planet orbits the Sun we get different views of the rings. Twice in every orbit only the edge of the outermost ring can be seen; even that can only be seen by using the strongest telescopes. Twice during the orbit we can see the fully opened rings.
- The rings all orbit Saturn at different speeds and have gaps between them. In 2010 a spacecraft from the NASA (US National Aeronautics and Space Administration) Cassini mission went between rings F and G and is now orbiting Saturn.
Figure 4: A Nasa photograph of Saturn’s rings taken from 5.5 million miles (8.9 million kilometres)