2017年托福听力科学美国人60秒：火星探测器出现液态水

　　科学美国人60秒中英文翻译：火星探测器出现液态水
　　This is Scientific American 60 Secomds, Space. I'm Clara Moskowitz, got a minute?
　　If Martians exist, even the microbial sort, they probably need liquid water. Temperatures on the surface of the red planet are below freezing, but signs exist that water flowed in the past—and perhaps still does, thanks to a Martian version of anti-freeze.
　　Salts lower the freezing point of water, as anyone knows who's thrown salt on an icy sidewalk. And both NASA's Phoenix and Curiosity missions found salts called perchlorates sprinkled around the Martian surface.
　　To see how perchlorates might act on Mars, researchers recreated the pressure, humidity and temperature of the planet inside a metal cylinder. They put a thin layer of perchlorates on top of water ice inside the chamber. Within minutes, droplets of liquid water formed, even at minus 100 degrees Fahrenheit.
　　Some scientists thought perchlorates might condense water vapor from the atmosphere. But within the cylinder, no liquid water formed in the presence of salts, either alone or on Mars-like soil, unless ice was present too. The study is in the journal Geophysical Research Letters.
　　The finding study could explain mysterious globules seen on the leg of the Phoenix in 2008. The lander may have been dotted with drops of otherworldly water.
　　Thanks for the minute for Scientific American 60 Secomds, Tech. I'm Clara Moskowitz.

　　科学美国人60秒中文翻译：
　　这里是科学美国人60秒，太空系列。我是克拉拉·莫斯科维兹。
　　如果火星人真的存在，即便是火星上的微生物也需要液态水。这个表面呈现红色的星球表面温度低于零度，但曾经竟然有水存在的潜在迹象，也许现在还有，这多亏了火星“特产”的防冻剂。
　　盐可以降低水的凝固点，在寒冷的冬季向多滑的地面和过道撒盐就是利用的这个原理。美国航空航天局发射的凤凰号和好奇号都在火星的表面发现了一种叫做高氯酸盐的物质。
　　火星液态水.jpg
　　为了研究液态水是如何在高氯酸盐的作用下形成的，科学家们砸在实验室内的金属桶内再造了着陆器的着陆环境，包括大气压力、湿度以及温度。他们在桶里的水冰上撒上了薄薄的一层高氯酸盐。即便室温只有零下100华摄氏度，几分钟之内，液态水还是形成了。
　　有科学家认为，高氯酸盐凝结了大气中的水蒸气从而形成液态水。不过实验表明，无论是在只有高氯酸盐的试验中还是将盐层放在类似火星的泥土上，当没有形成任何液态水，只有放在冰层上，液态水才可能形成。这项研究成果发布在《地球物理研究快报》上。
　　这项研究或许可以解释2008年凤凰号着陆器的腿上带有神秘的液态球状物体了。说不定，这就是来自外太空的液态水。托福考试(TOEFL)