Moving away from Jupiter, our next visitor is Saturn. Saturn is twice the distance from the sun than Jupiter is, so there is a long, cold gap between the two worlds. This isn’t surprising as the gravitational pull of these two planets would either capture or knock away any other object of any substantial mass. As much as Jupiter is the king of the solar system, Saturn is the queen. It’s iconic rings sitting like a crown around it in a way not seen on any planet in the solar system.
Facts about Saturn
Many of Saturn’s 62 moons are less than 20 km in diameter, there is evidence to suggest that there are many large moons in Saturn’s rings that are yet to be discovered. Looking in close detail at four of Saturn’s moons we find they are different world on a very cold theme.
Titan was the largest of Saturn’s moons, it was discovered by Christiaan Hyguens in 1655 and was the first to be discovered. It wasn’t named until 1847 however when John Herschel (Son of William Herschel – who discovered Uranus) published an extract on Saturn’s moons.
With a diameter 5,150km Titan is larger than Mercury, however not as massive. Titan is the only known moon in the solar system to have a thick atmosphere. Visual examinations of Titan have not yielded any information on Titan’s surface, only with radar scanning from the Cassini – Huygens probe in 2004 that any surface details were known. It’s atmosphere is a thick soup of 98% Hydrogen and 1.6% Methane. Information from the Cassini probe suggests that there are Methane lakes on Titan and that the thick atmosphere could be a primordial soup that could harbour or create life if the conditions permit.
Rhea was discovered in 1672 by Giovanni Domenico Cassini, however was not named until 1847 again by John Herschel . Rhea is an Icy world, made up from around 75% ice and 25% rock.
It is suggested that Rhea may have a ring system that isn’t easy observed. The data is unclear, but if it was so Rhea would be the only known moon in the solar system to have a ring system.
Enceladus was discovered in 1789 by William Herschel, little was know about this moon until the space age as it’s only 500km in diameter and observations were limited due to glare from Saturn. It was only until the space age that this small moon became far more interesting.
Enceladus is a world of frozen water, with a mix of new and old surfaces. The old oles marked with craters and the new surfaces smooth with huge cracks separating them.
Water volcanoes have been seen shooting water into space at immense speed, Cassini as been studying them and it’s now known that Saturn’s E ring had been created almost completely from the ejected matter from Enceladus.
Mimas had to be included in this little summary of Saturn’s moons. Yes, it is a moon and not a space station. That is all that needs to be said. A massive impact on Mimas in it’s history has created a feature that makes it look very much like the Death Star from Star Wars. It is however made from water and and rock and will not destroy planets.
Holst’s Saturn inspired musical piece for me definitely reflects a world that’s distant, cold and mighty. It has tunes that chill and inspire, it captures the sense of magnificence and beauty of Saturn
A number of probes have visited Saturn, Pioneer 10 was the first in 1979. In 1980 Voyager taking the first high definition pictures of the Saturn and some of its moons. Saturn’ s gravity flung the Voyager probe out of the plane of the solar system and out towards the stars.
Voyager 2 flew past in 1981 and made more measurements and took more pictures on its flyby, this time Saturn’s gravity was used to send Voyager 2 on towards Uranus.
In 2004 the Cassini-Huygens probe entered orbit around Saturn and began collecting data on Saturn and it’s moons. Titan was of particular interest and in December 2004 Cassini released the Huygens probe into Titans atmosphere.
It collected data on the atmosphere for several hours before it landed. It contained to send data for 90 minutes after it landed. Huygens is so far the most distant human object to have landed on another world.
Since 2004 Cassini has been passing by Saturn and its moons, finding out more and more about this mysterious world and it’s system of moons, how the rings were formed and what the moons are made of. One of the stark discoveries is that water seems to have been in good supply, the solar system seems in fact to have been soaked in water in it’s past. This is evident when examining Rhea and Enceladus in particular.
The Cassini mission came to an end in September 2017, after a series of dives within Saturn’s inner rings called the Grand Tour. The spacecraft was deorbited in order to prevent it contaminating any of Saturn’s moons. This ended a 20 year era of space exploration, but the data from Cassini will be studied for many years to come.
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