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0Life on Mars? 'Leopard-spot' rocks could be biggest clue yet
From: BBC
In September 2025, Nasa announced tantalising evidence that life may have once inhabited Mars. It was found in mudstones collected by the Perseverance rover at the bottom of a canyon, carved out by an old river in Jezero Crater.
Analysis of the rock samples by Perseverance's onboard instruments found minerals in the rocks – an iron sulphide known as greigite and a iron phosphate called vivianite – that were laid down in a ways similar to those left behind by microbes here on Earth.
Taken together Nasa's scientists say this could be a potential "biosignature" of past life.
It's far from conclusive, however, meaning more investigation is needed, which is unlikely unless the samples can be returned to Earth.
Susanne Schwenzer, a planetary scientist at The Open University in the UK and a member of the Mars Sample Return science team, says the presence of past life on Mars could leave a fingerprint in the interaction of its rocks and water. "If you have life, things look very different," she says. "If we have the samples from Mars, we can go into miniature detail to study these processes."
It's possible some of the samples could even contain fossilised microbes inside the rocks. "I as a scientist wouldn't have spent my life on this if I weren't hopeful that we have a good chance of finding something," says Schwenzer. "I hope we wil, but I can't predict it."
But even if signs of life on Mars were to be detected, it would not be unequivocal proof of widespread alien life elsewhere in the universe.
Mars and Earth are known to have shared material early in their history, meaning they might also have shared the genesis of life.
For evidence of a true second genesis, proof that life arose for a second time independently on another world, scientists are looking to the solar system's icy moons such as Jupiter's Europa and Saturn's Enceladus, thought to contain vast oceans beneath their frozen surfaces.
"If we were to find life on the icy moons, we would be sure this is a different genesis of life from Earth," says Schwenzer.
analysis /əˈnæləsɪs/ n. 分析
📗例句：A detailed analysis of the data is required.
（需要对数据进行详细分析。）
instrument /ˈɪnstrəmənt/ n. 仪器；工具
📗例句：The microscope is an essential instrument for biologists.
（显微镜是生物学家的必备工具。）
conclusive /kənˈkluːsɪv/ adj. 决定性的；确凿的
📗例句：The investigation did not yield any conclusive results.
（调查没有得出任何确凿的结果。）
🥝搭配：conclusive evidence 确凿的证据
microbe /ˈmaɪkrəʊb/ n. 微生物
📗例句：This powerful soap can kill most microbes.
（这种强力肥皂能杀死大多数微生物。）
