英语听力:自然百科 行星旅行指南:火星 Mars—9(在线收听

 Want to step outside to take in the scenery or pick up some rocks? As familiar as it might look beyond the port hole, Mars is dangerously alien. The upside is the low gravity will give you super jumping abilities, the down, the almost complete lack of atmosphere. This is not home. There is nothing here to breathe. To find similar conditions of low temperature and pressure on earth, you have to travel three times higher than a commercial airplane to the very edge of space. 

Planetary scientist Bob Brown shows why you should keep your helmet on when visit Mars.
 
“We have this just a beaker full of water. We have put it in this little chamber, and attach a vacuum hose to the chamber and pull the air out of the chamber.”
 
As the pressure drops to Martian levels, the water boils at room temperature.
 
“So if you are to take your helmet off on Mars, the liquid in your face especially will start to boil and much the same as this liquid water started to boil, and I guess I don’t have to describe what that might feel like or what it might look like.”
 
A medical travel advisory might say to keep your suit tightly fitted. But so far, no one has built a suit that would work on Mars. Existing spacesuits are simply too bulky, too heavy and too complicated to wear for the sort of regular activity required on the unforgiving surface of Mars.
 
“Something we take for granted here, we get up in morning, I put on a shirt and a pair of jeans and out I go. So it’s got to be routine, easy to use. Many times I’ve been working out in the field in the Antarctic and the Arctic, and I just have to take the gloves off as I’m doing something that requires that quintessential human capability of touch, feel and hold. So my request to the engineers is give me a spacesuit with gloves that will keep me warm and keep me pressurized, but still allow me to use (my hands.)”
  原文地址:http://www.tingroom.com/lesson/zrbaike/2012/260579.html