【听力】外星人可以通过听力“现身”

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当我们寻找地球以外的生命时，通常会搜索其化学特征。例如，最近在火星上发现的甲烷排放，就有可能是细菌生命的存在迹象。但生命探测的确还有另一种方式。看它是否会动。

"Everything moves.[laughter] I'm looking for something that I know that should be alive and does not move, but up to now I have not seen anything like this." Giovanni Longo, a physicist at the École Polytechnique Fédérale in Lausanne, Switzerland. “It’s extremely interesting, because it gives us a possible new definition of life if you want. If it moves, then it's alive."

“所有生物都在动。[笑声]而我在寻找一种我知道它有生命但又不动的生物，但目前为止我还没有见过任何像这样的生物。”瑞士洛桑市联邦理工学院的物理学家乔凡尼·朗格说。“这非常有趣，因为如果你接受这个想法，那它就赋予生命一个可能的新定义。如果它会动，那它就是有生命的。”

Longo and his colleagues studied the movements of bacteria, yeast, mouse, human and plant cells, using the nanosensor in an atomic force microscope. And they found that every living cell they studied vibrated in tune with the metabolic processes going on inside. When they altered bits of the cells' metabolism, the vibrations changed; when they killed the cells in the sample chamber--the vibrations stopped. The findings appear in the Proceedings of the National Academy of Sciences.

朗格和他的同事们利用原子力显微镜的纳米传感器，研究了细菌、酵母、小鼠、人类以及植物细胞的运动。他们发现，被研究的每一个活细胞都随着内部的新陈代谢活动协调地振动着。当他们对细胞的新陈代谢做出稍微调整时，振动也随之改变;当他们杀死样品库的细胞时，振动也随之停止。该项研究成果发表于《美国国家科学院院刊》。

Using their nanosensor search technique, the researchers were able to detect the vibrations of life in soil and water samples, too. So why not do the same thing on Mars? An atomic force microscope has in fact already been sent there, on the Phoenix Lander, though it wasn't set up to do these types of analyses. "But it can be done, so next time they can just modify it a little bit." And in doing so - expand our suite of life-detecting tools.

利用纳米传感器搜索技术，研究人员还能够在土壤样本和水的样本里检测出生命的振动。既然如此，为何不在火星上也这样做呢?尽管并非为了进行此类研究而设置，但确有一个原子力显微镜“乘坐”凤凰号着陆器被送达火星。“但这是可以做到的，只要下次工作人员对它稍作修改就行。”并且这样做还增加了生命探测工具的套件装备。