Excerpt from The Secret Lives of Planets: Order, Chaos, and Uniqueness in the Solar System, Paul Murdin
Saturn's moons play a critical part in controlling the rings, by pulling the individual particles of the rings away from some orbits and into others. This is what sorts the particles into rings and gaps. The process is called 'shepherding', as if the particles were sheep being chivvied by a sheepdog to take a particular route.
Excerpt from The Secret Lives of Planets: Order, Chaos, and Uniqueness in the Solar System, Paul Murdin The ocean hidden in Ganymede is perhaps 1,000 kilometres (600 miles) deep, and like Europa's ocean holds as much or more water than on Earth. Callisto's ocean is only a few hundred kilometres deep. Like Europa's oceans, these oceans (if they do indeed exist) may have life swimming in them.
Excerpt from The Secret Lives of Planets: Order, Chaos, and Uniqueness in the Solar System, Paul Murdin Europa looks like a world in stasis, but there is activity below its icy surface. The ice is a kilometre thick, floating on an ocean of salty water perhaps 5 kilometres (3 miles) deep. The water is warmed from below by geothermal energy. When the ice floes thrust together, they make hills of ice on the surface, but they are only a couple of hundred metres high. ... Altogether, there is more water on Europa than there is on Earth.
Excerpt from The Secret Lives of Planets: Order, Chaos, and Uniqueness in the Solar System, Paul Murdin Io is only a little larger than our own Moon. It is slightly ellipsoidal (the shape of a rugby football, or an American football); Jupiter's tidal forces have locked on to the long axis, which points towards the parent planet, so that, like all the Galilean satellites, Io gazes at Jupiter with the same face all the time.
Excerpt from The Secret Lives of Planets: Order, Chaos, and Uniqueness in the Solar System, Paul Murdin Although it is much less massive, Jupiter's gravitational pull on the Sun is so strong that the Sun is not really stationary in the middle of the solar system: instead, the two objects revolve around their centre of gravity, a point which lies near the service of the Sun.
Excerpt from The Secret Lives of Planets: Order, Chaos, and Uniqueness in the Solar System, Paul Murdin |
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