Moons of our Solar System
Moons of our Solar System

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Moons of our Solar System

Week 3: Looking closer


Find out about ancient volcanism on the Moon and elsewhere, as well as present-day hot volcanism on Io and icy volcanism on Enceladus. Discover the heat source that keeps such small bodies active.

First of all, Jess introduces the whole week.

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Hello again. So we’ve looked at orbits and craters and now we’re going to look at volcanism on moons. There’s plenty of evidence that volcanoes erupted on our Moon in the past. They’ve also erupted, and continue to do so, on other moons. Jupiter’s ‘Io’ has an enormous amount of volcanic activity, even today. We’ll also look at cryovolcanism on certain moons, where the erupted material is not magma made from molten rock, but fluid and gas extracted by melting icy material.
There’s a really cool video clip of an eruption plume on Io, recorded by a probe called New Horizons as it flew past Jupiter on its way to Pluto. I hope you enjoy it. We’ll then pause to consider the significance of the discovery of Jupiter’s four large moons by Galileo just over 400 years ago. It paved the way for the acceptance of Copernicus’ theory, that the planets revolve round the Sun, not the Earth.
See if you can spot the famous actor playing Galileo, in an extract from an Open University dramatisation made in the 1990s. Then we move on to Europa, another of Jupiter’s moons, and arguably the place in our Solar System most likely to host extra-terrestrial life. Most of our knowledge of Europa comes from a space probe, named Galileo. To finish the week, we’ll examine small moons. These are so small that even their gravity is too weak to pull them into spherical shapes.
We’ll also see that even asteroids can have moons. There’s a brilliant clip of a radar movie showing a 600 metre wide moon orbiting a 2.7 kilometre asteroid that flew past the Earth in 2013. We’ll also meet some of the weird and wonderful moons of Saturn, and find out what we know so far about Pluto’s moons, which will be visited for the first time in July 2015. It’s a good week, this one.
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By the end of this week, you should be able to:

  • understand the significance of volcanic activity on moons
  • consider the importance of Galileo’s discovery of four moons around Jupiter
  • consider the place in our Solar System that is most likely to host extraterrestrial life.

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