英语听力:自然百科 行星旅行:土星 Saturn—8(在线收听

 Saturn’s apparently peaceful appearance is due to a haze of high level ammonia in the upper atmosphere,  by looking deep into Saturn in the infrared, using the planet’s own internal heat as a light source, Cassini has revealed the planet’s true nature. 

 
The winds on Saturn vary dramatically from the equator to the pole. / In fact, at the equator we have huge winds, wherein close to 900 miles an hour now, near the speed of sound in that planet. 
 
The winds are stronger at Saturn than they’re in Jupiter, and that’s a surprise, because the two planets are rather similar in terms of basic composition, they’re both gas giants and yet Saturn has less sunlight to power the winds, and the winds are stronger. 
 
 
Try explaining the 6-sided vortex at the North Pole. Saturn has a hexagon, it’s some kind of a wave, but it’s a permanent wave. It’s been there since Voyager discovered it back in 1980. So this is just one more example of how atmospheric features which are basically nothing but gas. They last forever on these giant planets. 
 
 
There is another permanent storm at the South Pole, not quite too strange, but gigantic in size. At 5,000 miles across, you could almost fit the whole earth inside. The South Pole has something that looks very much like a hurricane eye, except the clouds are 5 times the height of the eye wall around a terrestrial hurricane. So it’s kind of a window into the depth of Saturn, showing us just how dynamic the planet really is, and it’s sort of kind of need.
 
 
And at the bottom of this window, storms within the storm, adding their own level of complexity to the weather forecasts of this alien planet are the rings. For half a Saturnian year, the rings block the light in the northern hemisphere, and the other half of the year, it’s blocked in the southern hemisphere.
  原文地址:http://www.tingroom.com/lesson/zrbaike/2012/260598.html