隐藏的王国：土星新发现百余颗卫星

The discovery of another 100 moons around Saturn could help us solve the mystery of how the planet’s rings formed, finds Jonathan O’Callaghan PLANET VOLUMES/UNSPLASH I N THE far reaches of the solar system, the planetary neighbourhood seems quiet. Beyond Jupiter, the sun is no longer a blazing disc, but a cold, white lamp. The planets are separated by gulfs of darkness. Light takes just 8 minutes to get from the sun to Earth, but typically more than an hour to cross the yawning chasm between Uranus and Neptune. What is a moon, exactly? If you looked up at our night sky, you would see our own natural satellite, more than 3400 kilometres across, keeping stately company with Earth. …