英语听力：自然百科 行星旅行指南：火星 Mars—15

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The water ice is proof of a valuable resource for any life forms still clinging(附着) beneath the surface and for future travelers. 

 

We now know that these plants that you see / stretching behind me are under land only 2 or 3 inches deep by a sheet of ice, all the way as far as you can see. Great hockey ring, if you had a hockey team on Mars, all you need is a broom. 

 

The possibility of running into Martians received another boost from a very Mars like part of our own planet, Chile’s extraordinary Atacama Desert.The Atacama is special because it is just so profoundly dry, speaking roughly, 15 times dryer² than Death Valley. It is deader than Death Valley. It is the only place on earth where Viking could have landed and searched for life in dirt on earth and not found it, and instead, found a reactive mixture of chemicals, the only place. 

 

 

Even here, in the driest corner of the driest desert on earth, life has confounded scientists, Cyano-bacteria have been found living inside the rock hard salt of a long-gone lake. 

 

This is halite, this is sodium³ chloride salt, which is colonized⁴ by Cyano-bacteria. It is dark green because they have this particular pigment⁵ protecting them from the excess of UV light. 

 

Once in a blue moon, a fleeting⁶ early morning ground fog delivers some rare humidity to the air above the desert, this precious moisture is greedily sucked into the microscopic⁷ pores of the water- hungry rock/ salt. 

 

This is a very rare event, so these bacteria are only living in an environment where liquid water is available a few hours during one year, very, very hard.

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