Mars's Volcanoes May Only Be Asleep
火星的火山也许只是睡着了
欧空局 ExoMars 微量气体轨道器在阿尔巴山侧翼裂隙中探测到氯化氢逸出。这种气体在地球上由高温岩浆释放，暗示火星内部仍保有热量，火山可能只是休眠而非死亡；成果发表于《科学进展》。
A European orbiter found hydrogen chloride seeping from fissures on Alba Mons — a gas that on Earth comes from hot magma. The planet may retain enough heat to erupt again.
Mars may not be geologically dead after all. Observations from a European spacecraft suggest that the planet's volcanoes are dormant rather than extinct — asleep, in other words, and possibly capable of waking.
The claim rests on a gas. The ExoMars Trace Gas Orbiter has detected hydrogen chloride escaping from fissures on the flanks of Alba Mons, a volcano in the Tharsis region. On Earth, hydrogen chloride is a familiar volcanic emission, produced by hot magma below the surface. Finding it on Mars, in a place and a season where it should not be, is the kind of clue that forces a rethink.
The anomaly was seasonal. Hydrogen chloride on Mars normally peaks in winter and fades in summer, tracking the planet's water and dust cycles. On the flanks of Alba Mons, however, the concentration spiked in early summer.
The proposed explanation is elegant. Gas seeps up from depth during winter and is trapped by ice; in summer the ice sublimates — turns directly from solid to gas — and releases what it held, which is what the orbiter saw. Supporting the picture, the spacecraft spotted newly formed narrow fissures in the same area, some of them hundreds of feet long.
“The results suggest that Mars retains enough heat internally to have supported volcanic activity recently, and possibly even now,” Daniel Mège of the Polish Academy of Sciences, a co-leader of the study, told Space.com. He described the detection as looking for a needle in a haystack.
If a magma chamber is still sitting under that plumbing, the implications reach beyond geology. Past volcanic gases would have thickened the atmosphere and warmed the climate, and lava meeting groundwater would have created warm, wet pockets. Those are precisely the places to look for surviving microbes, Mège argues, because a hydrothermal system would supply both the material and the energy, while shielding anything living from the surface.
None of this amounts to an eruption. No lava flows or eruptive deposits have been found, and the case rests on chemistry and fresh cracks rather than on a volcano caught in the act. The work was published in Science Advances on 4 November.
中文翻译（全文）
火星也许并没有在地质意义上死去。来自一架欧洲探测器的观测显示，这颗行星上的火山只是休眠，而不是熄灭——换句话说，是睡着了，而且可能还会醒来。
这一结论的依据是一种气体。ExoMars 微量气体轨道器在阿尔巴山侧翼的裂隙中探测到氯化氢正在逸出。在地球上，氯化氢是常见的火山排放物，由地下的高温岩浆产生。而在火星上、在一个它本不该出现的地点与季节发现它，正是那种迫使人们重新思考的线索。
这种异常具有季节性。火星上的氯化氢通常冬季达到峰值、夏季消失，跟随这颗行星的水循环与尘埃循环。但在阿尔巴山侧翼，其浓度却在初夏骤升。
研究给出的解释很优雅：气体在冬季自深处向上渗出，被冰层封存；到了夏季冰层升华——直接从固态变为气态——把原本困住的气体释放出来，这正是轨道器看到的情形。作为佐证，探测器在同一区域发现了新形成的狭窄裂隙，其中一些长达数百英尺。
「结果表明，火星内部保留的热量足以支撑它在不久前发生火山活动，甚至可能至今仍然如此。」该研究的联合负责人、波兰科学院的 Daniel Mège 对 Space.com 表示。他形容这次探测如同大海捞针。
如果那套「管道」下面仍存在岩浆房，影响就超出地质学范畴。过去的火山气体本会使大气变厚、气候变暖，而熔岩与地下水相遇则会造出温暖湿润的局部环境。Mège 认为，这些恰恰是寻找幸存微生物的地方——热液系统既能提供物质与能量，又能替生命挡住地表的恶劣条件。
不过这一切都还不等于一次喷发。目前没有发现熔岩流或喷发沉积物，整个论证依赖化学信号与新出现的裂缝，而不是一座正处于喷发中的火山。相关成果于 11 月 4 日发表在《科学进展》上。
重点词汇
- dormant /ˈdɔːmənt/ adj. — not active now but capable of becoming active again 休眠的 The volcanoes may be dormant rather than extinct.
- extinct /ɪkˈstɪŋkt/ adj. — no longer active and unable to become active again 熄灭的；死火山 Mars was thought to be geologically dead.
- fissure /ˈfɪʃə/ n. — a long narrow crack in rock 裂隙 Gas escaped from fissures on the flank.
- flank /flæŋk/ n. — the side of a mountain or volcano （山体）侧翼 The fissures lie on the volcano's flank.
- seep /siːp/ v. — to flow slowly through small openings 渗出 Gas seeps up from depth in winter.
- sublimate /ˈsʌblɪmeɪt/ v. — to change directly from solid to gas 升华 The ice sublimates in summer.
- magma chamber /ˈmæɡmə ˈtʃeɪmbə/ n. — a body of molten rock beneath a volcano 岩浆房 A magma chamber may still sit below.
- hydrothermal /ˌhaɪdrəʊˈθɜːml/ adj. — relating to hot water in the ground 热液的 A hydrothermal system could support microbes.
- emission /ɪˈmɪʃn/ n. — something released into the air 排放物 Hydrogen chloride is a volcanic emission.
- deposit /dɪˈpɒzɪt/ n. — material left behind by a natural process 沉积物 No eruptive deposits have been found.
阅读测验
共 5 道题目
What is the new claim about Mars?
What did the orbiter detect?
On Earth, hydrogen chloride is produced by hot magma below the surface.
Which evidence supports the explanation? (Select all that apply)
The paper was published in Science _____ on 4 November.
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