火星漫游者在这个红色行星的地表下探测到了原始生命的迹象

火星的漫游者好奇号已经在红色行星上发现了一个潜在的生命迹象——这个星球历史上对于甲烷气体的最高水平的测量结果。

地球上,甲烷主要来源于呼出甲烷的微生物。按照NASA的推测,隐藏在火星地壳下面的生物可能也是最近的测量结果的原因。但是现在请别过于兴奋,因为生命不是对于这个发现的唯一的可能解释。NASA指出,甲烷也能够由岩石和水之间的化学反应产生。

“从我们现在的测量结果来看,我们没有方法去判断甲烷的来源是生物还是地质。”位于绿地、马里兰州的NASA戈达德航天中心的主要研究者保罗马哈菲在一项声明中说道。

况且,这个破纪录的甲烷测量结果和地球上的甲烷含量的平均值相比较也显得更逊色。

好奇号测出的火星上的甲烷含量是10亿方分之21(ppb)。相比较而言,地球的甲烷含量接近1860ppb。

好奇号在过去曾经检测到过甲烷,虽然含量比这次要低很多。火星上甲烷含量的平均值接近于10的9次方分之7。可是根据NASA,甲烷含量确实随着季节的变化而升高或降低。这个模式提供了关于甲烷的来源的潜在的证据。在火星的冬季,甲烷含量减少。在夏天,它们的含量再次增多。科学家们知道,在红色行星的地壳底下躺着一层冰。也许在夏季,冰融化了,向火星的大气层释放出原来被困在冰层中的甲烷其气泡(与地球北极地区的冰冻土层在自己融化的同时向大气层释放出甲烷气体相似)。按照NASA的推测,这些甲烷气泡有可能是生命的遗迹。

甲烷不是火星曾经拥有古代生命适宜的环境的唯一证据。在2012年,好奇号与火星一个河床里识别出了存在了30亿年的水的化学痕迹。其后一年,科学家们在由好奇号于相同地点附近采集的岩石样本中认出了生命的一些化学组成部分。

欧洲航天局的微量气体轨道飞行器已经在火星轨道飞行了一年多了,还没有测量出一点甲烷。通过与微量气体轨道飞行器小队合作,NASA的科学家们希望最终解决火星上甲烷的秘密,并找到这种天然气的来源。

本文来自于

Mars Rover Detects Primordial Signs of Life Under the Red Planet’s Surface

By Isobel Whitcomb, Live Science Contributor | June 24, 2019 03:41pm ET

The Mars rover Curiosity has uncovered a potential sign of life on the Red Planet — the planet’s highest-ever measurement of a natural gas called methane.

On Earth, methane primarily comes from microbes, who breathe out the gas. It’s possible that life-forms hiding under Mars’ crust are also responsible for this latest measurement, according to NASA. But don’t get too excited — yet. Life isn’t the only potential explanation for the finding. Methane is also created by chemical reactions between rocks and water, according to NASA. [9 Strange, Scientific Excuses for Why Humans Haven’t Found Aliens Yet]

“With our current measurements, we have no way of telling if the methane source is biology or geology,” principal investigator Paul Mahaffy of NASA’s Goddard Spaceflight Center in Greenbelt, Maryland, said in a statement.

Plus, even this record-high methane measurement pales in comparison with average methane levels on Earth. Curiosity measured methane concentrations of 21 parts per billion (ppb) on Mars. In comparison, Earth’s methane concentrations are close to 1,860 ppb.

Curiosity has detected methane in the past, albeit at much lower concentrations. The average level on Mars is close to 7 ppm. But methane levels do appear to rise and fall seasonally, according to NASA. And this pattern offers a potential clue about the source of the methane. During the Martian winter, concentrations fall. In the summer, they rise once more. Scientists know that beneath the Red Planet’s crust lies a layer of ice. Perhaps, in summer, ice thaws, releasing trapped bubbles of methane into the atmosphere (similar to the way Earth’s arctic permafrost releases methane into the atmosphere as it melts). These methane pockets could be a relic of ancient life, according to NASA.

Methane isn’t the only evidence that Mars was once hospitable to ancient life. In 2012, Curiosity identified chemical traces of 3 billion-year-old water in a Martian streambed. The following year, scientists identified some of the chemical building blocks of life in a rock sample collected by Curiosity near that same site.

The European Space Agency’s Trace Gas Orbiter has been in orbit around Mars for over a year and has yet to measure any methane. By partnering with the Trace Gas Orbiter team, NASA scientists hope to eventually solve the Mars methane mystery and find the source of the natural gas.

火星上的漫游者在红色行星的地表下探测到了生命原始的迹象

火星的漫游者好奇号已经在红色行星上发现了一个潜在的生命迹象——这个星球历史上甲烷气体的最高浓度的测量结果。

地球上,甲烷主要来源于呼出甲烷的微生物。根据NASA,隐藏在火星地壳下面的生物可能也是最近的测量结果的原因。但是现在请别过于兴奋。生命不是对于这个发现的唯一可能的解释。根据NASA,甲烷也能够由岩石和水之间的化学反应产生。

“从我们现在的测量结果来看,我们没有方法去判断甲烷的来源是生物还是地质原因。”位于绿地、马里兰州的NASA戈达德航天中心的主要研究者保罗马哈菲说道。

再说,即使这个破纪录的甲烷测量结果和地球上的甲烷含量的平均值相比较也显得逊色。

好奇号测出的火星上的甲烷含量是10的9次方分之21。相比较而言,地球的甲烷含量接近10的9次方分之1860。

好奇号在过去已经检测到过甲烷,虽然含量比这次要低很多。火星上甲烷含量的平均值接近于10的9次方分之7。可是根据NASA,甲烷含量确实随着季节的变化而升高或降低。这个模式提供了关于甲烷的来源的潜在的证据。在火星的冬季,甲烷含量减少。在夏天,它们的含量再次增多。科学家们知道,在红色行星的地壳底下躺着一层冰。也许在夏季,冰融化了,向火星的大气层释放出原来被困在冰层中的甲烷其气泡(与地球北极地区的冰冻土层在自己融化的同时向大气层释放出甲烷气体相似)。根据NASA,这些甲烷气体有可能是生命的遗迹。

甲烷不是火星曾经拥有古代生命适宜的环境的唯一证据。在2012年,好奇号与火星一个河床里识别出了存在了30亿年的水的化学痕迹。接下来一年,科学家们在由好奇号于相同地点附近采集的岩石样本中认出了生命的一些化学组成部分。

欧洲航天局的微量气体轨道飞行器已经在火星周围的轨道待了一年多了,还没有测量出一点甲烷。通过与微量气体轨道飞行器小队合作,NASA的科学家们希望最终解决火星上甲烷的秘密,并找到这种天然气的来源。

 

本文来自于:

Mars Rover Detects Primordial Signs of Life Under the Red Planet’s Surface

Mars Rover Detects Primordial Signs of Life Under the Red Planet's Surface
NASA’s Curiosity rover has found a sky-high amount of methane while sampling in Mars’ Gale Crater (shown here).

Credit: NASA

The Mars rover Curiosity has uncovered a potential sign of life on the Red Planet — the planet’s highest-ever measurement of a natural gas called methane.

On Earth, methane primarily comes from microbes, who breathe out the gas. It’s possible that life-forms hiding under Mars’ crust are also responsible for this latest measurement, according to NASA. But don’t get too excited — yet. Life isn’t the only potential explanation for the finding. Methane is also created by chemical reactions between rocks and water, according to NASA. [9 Strange, Scientific Excuses for Why Humans Haven’t Found Aliens Yet]

“With our current measurements, we have no way of telling if the methane source is biology or geology,” principal investigator Paul Mahaffy of NASA’s Goddard Spaceflight Center in Greenbelt, Maryland, said in a statement.

Plus, even this record-high methane measurement pales in comparison with average methane levels on Earth. Curiosity measured methane concentrations of 21 parts per billion (ppb) on Mars. In comparison, Earth’s methane concentrations are close to 1,860 ppb.

Curiosity has detected methane in the past, albeit at much lower concentrations. The average level on Mars is close to 7 ppm. But methane levels do appear to rise and fall seasonally, according to NASA. And this pattern offers a potential clue about the source of the methane. During the Martian winter, concentrations fall. In the summer, they rise once more. Scientists know that beneath the Red Planet’s crust lies a layer of ice. Perhaps, in summer, ice thaws, releasing trapped bubbles of methane into the atmosphere (similar to the way Earth’s arctic permafrost releases methane into the atmosphere as it melts). These methane pockets could be a relic of ancient life, according to NASA.

Methane isn’t the only evidence that Mars was once hospitable to ancient life. In 2012, Curiosity identified chemical traces of 3 billion-year-old water in a Martian streambed. The following year, scientists identified some of the chemical building blocks of life in a rock sample collected by Curiosity near that same site.

The European Space Agency’s Trace Gas Orbiter has been in orbit around Mars for over a year and has yet to measure any methane. By partnering with the Trace Gas Orbiter team, NASA scientists hope to eventually solve the Mars methane mystery and find the source of the natural gas.