英語聽力：自然百科 火星也下雪？

　　NASA scientists report NASA’s Phoenix spacecraft has discovered evidence of past water at its Martian landing site and spotted falling snow for the first time on Mars. Soil experiments reveal the presence of two minerals known to be formed in liquid water on Earth.

　　"Phoenix has done a great job in helping us expand our understanding of water and climatic processes, and the water drivers in those, in the climate. The significant amount of science data collected by the Phoenix mission will last the science research community for a significant number of years to come. "

　　A laser instrument aboard the Phoenix recently detected snow falling from clouds, but it disappeared before reaching the ground. Phoenix landed on Mars in May for a three-month mission to study whether the environment could be friendly to microbial life. One of its biggest discoveries so far is confirming the presence of ice on the planet. Scientists think there could have been standing water at the site in the past, or the ice could have melted and interacted with the minerals. Mars today is cold and dry with no sign of water on the surface, but some scientists believe the planet once was warmer and wetter.

　　"The water is important. It’s one of the critical elements to sustain life. In our search for life, within the universe, this is a very critical element to understand what the history of that is and Mars is an easy place to get to …"