Published on July 13th, 2011 | by Yellow Magpie

Jupiter’s Moon Callisto: Gateway To The Stars?

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Jupiter’s Moon Callisto

Jupiter’s moon Callisto is the farthest of Jupiter’s giant moons. This heavily pock-marked satellite is one of the darkest worlds in the Solar System peppered by brighter craters – which reveal an icy underbelly.

A Non-Layered World

At 9,600 kilometres (6,000 miles), Jupiter’s moon Callisto is a formidable size for a moon. It orbits Jupiter at a distance of 1,800,000 kilometres (1,125,000 miles) taking just under 17 Earth-days to do so.

One of the most interesting things, something that we will get back to soon, is its composition. Composed mainly of rock and ice, Callisto has no differentiating layers below what is thought to be a salt-water ocean.

Jupiter’s Moon Callisto: A Strange Phenomenon

Strangely, when the Galileo probe passed by it detected a magnetic field. As Callisto’s interior does not have a core and is too far away from Jupiter to be affected by tidal heating, this left scientists slightly perplexed.

Further studies of this phenomenon have indicated that the moon is likely shielded from Jupiter’s powerful magnetic core by something beneath its crust, a substance that has the ability to conduct Jupiter’s magnetic field. Some have theorised that this is in fact a subterranean ocean of saltwater that could contain a type of anti-freeze such as ammonia.

If this ocean exists it could be as great as 300 kilometres (186 miles) deep. To put this in context, on Earth it is thought that roughly half of our oceans are 3,000 metres deep. This would mean that Jupiter’s moon Callisto could support an ocean that is on average 100 times deeper than that of our home planet.

An Older World

One of the most heavily cratered of any body in the Solar System, Callisto is very different from the other moons of Jupiter. Its surface is much older and it is believed that the crust has never been resurfaced unlike the other Galilean moons.

Jupiter’s moon Callisto is thought to be almost saturated by craters which means that new impacts have a high probability of wiping out existing craters.

The Moon’s Prospects

One of the most intriguing questions that is currently being asked about Jupiter’s moon Callisto is, does it support life? At present, because of its cold temperature and the fact that the moon is not heated by tidal forces means that it is implausible that it could support life unlike Europa which is a prime candidate.

The moon’s position in the Solar System could play a very important part in the future of humanity. Due to its distance from Jupiter, Callisto does not experience the high levels of radiation that the other Galilean moons have. This could see the satellite becoming a gateway to greater things. NASA has already drawn up tentative plans to send a manned mission as near as 2040 into the future.

Highly Recommended Reading

Check out Yellow Magpie’s Jupiter: The Local Gas Giant Of The Solar System for more insight into the largest planet in the Solar System and The Moons Of Jupiter: The Solar System Within The Solar System for a more detail look at Jupiter’s other moons.

You may also wish to take a gander at The Solar System And Beyond: A Guide To The Cosmos.

Cosmos is a highly recommended book. It contains large, full-page pictures of the asteroids and writing on the subject by the highly competent author, Giles Sparrow.

Amazon.co.uk
For people living in Ireland or the United Kingdom, you can access: Cosmos from here.

Amazon.ca
For those who live in Canada, you can obtain: Cosmos here.

Amazon.de
For Germany: Cosmos.

Amazon.fr
For France: Cosmos.