说明:
The Planets
Series 1: 4. Life Beyond the Sun: Saturn
Saturn is the jewel of the solar system, the most seductive of all the planets, but as Professor Brian Cox reveals - it wasn’t born that way.
Raised in the freezing outer reaches of the solar system, Saturn began life as a strange planet of rock and ice. Born outside the snow line, with an abundance of building materials, it soon grew to dwarf the Earth, drawing in colossal amounts of the hydrogen and helium that permeated the early solar system. In time Saturn was transformed into a gas giant, ring-less and similar looking to its great rival, Jupiter. As the gas giant grew, its original rocky form was lost forever, becoming part of the planet’s core, where temperatures are hotter than the surface of the sun, and pressures so intense that carbon there falls as diamond rain.
Saturn’s core isn’t the only part of it to change over time. As Nasa's Cassini probe has discovered, the planet remained ring-less most of its life - until a fateful encounter changed everything. Less than a hundred million years ago, one of Saturn’s ice moons was drawn too close to the planet. In a truly cataclysmic event the entire moon was destroyed and the rings where born.
But Saturn’s true beauty may have remained hidden forever if it wasn’t for the decision to send Cassini on a risky close encounter with another moon, Enceladus. There we discovered an ocean with similar conditions to places on Earth where life thrives. Way out, far beyond the Sun, hydrothermal vents have been found, the very same habitat that we think life here on Earth may have got its start.
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skorpion.
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