This is Scientific American's 60-second Science, I'm Christopher Intagliata.Just like here on Earth, we have earthquakes, the planet Mars has "Mars-quakes.""Although the quakes we see on Mars are actually more similar to the kinds of things we see in the middle of plates on the earth,what we call inter plate earthquakes.And so something that might happen in Montana or South Carolina, for example."Bruce Banerdt, a planetary geophysicist at the Jet Propulsion Lab in California.He explains that as the hot center of the planet cools, it slowly shrinks."So the frozen outer layers, basically, after a while, they're too big for the rest of the globe,and they have to kind of crinkle to stay, you know, contiguous on a shrinking ball."And that crinkling causes quakes.NASA's InSight mission, which landed on the Red Planet about a year ago,placed a seismometer on the planet's surface to listen for quakes.And it's captured signals from more than 100―some large enough that you'd feel them if you were standing nearby.Like this magnitude 3.7, recorded back in May.Just to know, it's been sped up to be audible―and you really need headphones to hear the ferocious rumbling."We use these signals from Mars-quakes to probe the deep interior of Mars. They work almost like x-rays, you know.They pass through the planet; they bounce off boundaries, like between the crust and the mantle, the way an x-ray bounces off a bone.
这里是科学美国人――60秒科学系列，我是克里斯托弗・因塔格里塔。和地球一样，我们有地震，火星上也有“火星地震”。“尽管我们在火星上看到的地震实际上更类似于地球板块间的地震，我们称之为――板缘地震。比如蒙大拿州或南卡罗莱纳州可能发生的那种地震。”加州喷气推进实验室的行星地球物理学家布鲁斯・巴纳特说到。他解释说，火星会随着其炎热中心的降温而慢慢缩小。“因此，一段时间之后，冰冻的外层对于火星其余部分来说会过于庞大，外层不得不皱起才能与不断缩小的球体保持相连。”这种皱起会引发地震。一年前，美国国家航空航天局（NASA）的“洞察”号探测器在火星登陆，并在火星表面放置了地震仪来监测地震。其从100多个信号中捕捉地震信号，有些信号大到你站在附近都能感觉到。比如5月份记录下的这场3.7级地震。信号已加速到可以听到的程度――你真的需要戴上耳机听听这些凶猛的隆隆声。“我们利用这些火星地震信号来探测火星深处。信号的工作原理就像X光一样。信号穿过火星，遇到地壳和地幔之间的边界反弹，就像X光遇到骨头反弹一样。
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