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Time: 17 hours
Level: Intermediate
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 Introduction Resource- Until the 1980s, the icy satellites of the outer planets were scarcely thought of as places where life could ever have existed. Few could have imagined that one of them, Europa, would within twenty years...
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| | 1 Icy satellites: introduction
- 1.1 Satellite discoveries Resource
- Pisa-born pioneer of the experimental scientific method, Galileo Galilei's analysis of motion paved the way for Isaac Newton's work. He used one of the first telescopes to discover the four largest of...
- 1.2 Satellite systems and their origins Resource
- The satellite systems of the giant planets have several features in common. Most satellites are in synchronous rotation, always keeping the same face towards their planet. Irregularly shaped moonlets associated...
- 1.3 Unravelling the natures of the large satellites Resource
- Before the dawn of the space age, relatively little could be discovered about even the large satellites. Their orbits were well known, and from the subtle orbital perturbations caused by neighbouring satellites...
- 1.4 The discovery of tidal heating Resource
- The Voyager fly-bys of the Jupiter system convinced planetary scientists that former preconceptions about ‘dead’ globes were wrong – even before Voyager 1 had got as far as Saturn, the mission had enabled...
- 1.5 The Galileo mission Resource
- It was a long time before the Voyager missions were followed up by more detailed surveys of the outer planet satellites. No Uranus or Neptune missions are planned, but a mission to Saturn called Cassini-Huygens...
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- 2.1 Introduction Resource
- Europa's surface is fascinating, if often perplexing, to study. One of its special characteristics is its brightness. It has an albedo of 0.7, which is exceeded among icy satellites only by Enceladus and...
- 2.2 Ice and salt Resource
- As noted in Section 1.5, Europa's near-infrared reflectance spectrum was used as long ago as the 1950s to demonstrate that its surface is mostly water-ice. More recently, spectroscopic observations by...
- 2.3 Examining Europa's surface Resource
- It is all very well speculating about conditions in an ocean below Europa's ice, but what evidence is there that it actually exists? After all, tidal heating might not result in ice melting on a global...
- 2.4 How thick is Europa's ice? Resource
- You learned in Section 1.4 that geophysical data show the ‘icy’ outer part of Europa to be about 100 km thick, but that the information is inadequate to distinguish between the extreme possibilities of...
- 2.5 Heat and life Resource
- The weight of evidence in the case of Europa points strongly towards ice overlying salty water, at least within the past few millions years although not necessarily today. There are signs that localised...
- 2.6 How can we find out more about Europa? Resource
- There are currently no scheduled missions to Jupiter's moons, since NASA's Jupiter Icy Moons Orbiter (JIMO) was cancelled in 2005, but Europa remains a high priority target for both NASA and ESA, so a...
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| | 3 Other icy bodies as abodes of life?
- 3 Other icy bodies as abodes of life? Resource
- You have seen that Europa offers arguably the most promising habitat for present-day life in the Solar System, other than on the Earth itself. This is because ice or water overlying warm rock can lead...
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- 4 Unit summary Resource
- Many of the large icy bodies in the outer Solar System are internally differentiated. Thanks largely to tidal heating, some, especially Europa, are likely to have an ocean sandwiched between the icy exterior...
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| | References and Acknowledgements | |
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