英语听力：自然百科 行星旅行：土星 Saturn—11（在线收听） |
Here’s the surprise entry into search for life, this little moon that you’d expect to be pretty dead and dull, and coming out of the South Pole of it is a jet of water ice, all the things you need for life are there. There’s an energy source, there’s a water source, there’s an organic material source, there’s a nitrogen source, check, check, check, check, all the requirements for life. This is the little moon that has it all, and the samples are coming out in space, there’s a big sign there “Free samples, take one.” We just fly through and grab it on our way. I think it is the go to place on our solar system right now for investigating issues of astrobiological importance. It wins out the game over Mars, over Europa, over Titan even, simply because of accessibility, it’s accessible, if these jets are deriving from liquid water, then they are there for the sampling,
The Cassini teams has been flying the spacecraft at height as low as 15 miles on its way to the plumes, unbelievable precision flying for a remotely controlled robot that was never designed for such a feat, a billion miles from earth.
From Cassini we learned that there’s methane in the plume, nitrogen in the plume, ammonia in the plume, organic molecules in the plume. It’s a real soup, we’re seeing a soup of organics being spewed out into space or it’s frizzy, you can almost go there and jar it, put it in a can and sell it on earth as organic nutrient soup,
On earth, geysers and hot springs are home to bacteria with pedigrees dating back to the beginning of life. They can also be breathtaking, but nothing on earth matches the Saturnian cold faithful.
The sitting there in the South Pole of Enceladus, and taking a look at Saturn, while you’re sitting there watching this eruption going on would be beautiful,
It wouldn’t be a dangerous thing, you would see these towering, towering dramatic thousands of just icy particles. We’d never see them stop because some of them actually extend/ tens of thousands of kilometers into the space above the South Pole, and in fact into orbit around Saturn. This is how the e-ring of Saturn is formed. |
| 原文地址：http://www.tingroom.com/lesson/zrbaike/2012/260603.html |