一项新的研究给火星生命的希望带来了巨大的打击

一项新的研究给火星生命的希望带来了巨大的打击

Of all the planets in our solar system, Mars is thought to be our best chance at finding life outside of Earth. There’s obviously not much happening on the surface, but pockets of ice and even water exist in some areas of the planet, and there’s a tiny, almost impossibly slim chance that something very tiny might be living there.

在我们太阳系的所有行星中，火星是我们在地球之外寻找生命的最佳机会。表面上不太可能，但是在这颗星球的某些区域存在着冰甚至水，所以在那里生存的机会还是有非常微小的可能的。

Or, at least that’s what some scientists were hoping for, but a new study published by researchers from several institutions suggests that even that narrow possibility is probably also nonexistent.

或者，至少这是一些科学家所希望的，但来自几个机构的研究人员发表的一项新研究表明，即使是这种微小的可能性也可能不存在。

We think we have a pretty good idea of what ingredients are required for life to exist. One of the big ones is water, and Mars has it. Much of it is locked away in ice, but Mars also has salt, and the combination of water and salt dramatically lowers its freezing point, meaning that puddles of ultra-salty brine could still exist on the surface.

我们以为我们对生命存在所需要的成分有了很好的了解。其中最大的一个是水，火星上就有水。火星上的大部分冰都被锁住了，但火星上也有盐，水和盐的结合大大降低了火星的冰点，这意味着火星表面仍然可能存在超咸盐水坑。

To determine the likelihood that such puddles could support life, the researchers built an atmospheric model based on what we already know about the planet. Then using the simulated climate, they tested whether briny puddles could persist for long periods of time. Unfortunately, the data points in the opposite direction of life.

为了确定这些水坑能够维持生命的可能性，研究人员根据我们对火星的了解建立了一个大气模型。然后利用模拟的气候，他们测试了盐水水坑是否能长期存在。不幸的是，这些数据指向相反的方向。

“Our team looked at specific regions on Mars — areas where liquid water temperature and accessibility limits could possibly allow known terrestrial organisms to replicate — to understand if they could be habitable,” Dr. Alejandro Soto, co-author of the study, said in a statement. “We used Martian climate information from both atmospheric models and spacecraft measurements. We developed a model to predict where, when and for how long brines are stable on the surface and shallow subsurface of Mars.”

我们的团队研究了火星上的特定区域——液态水温度和可接近性限制可能允许已知陆地生物复制的区域——以了解它们是否适合居住，”该研究的合著者亚历杭德罗·索托博士在一份声明中说。“我们使用了来自大气模型和航天器测量的火星气候信息。我们开发了一个模型来预测盐水在火星表面和浅地下稳定的时间、地点和持续时间。”

The results showed that even under the most favorable conditions, puddles of super-salty water would only be stable on the planet’s surface during certain times of the year.

结果表明，即使在最有利的条件下，超咸水坑也只会在一年中的某些时候稳定地存在于火星表面。

“Even extreme life on Earth has its limits, and we found that brine formation from some salts can lead to liquid water over 40% of the Martian surface but only seasonally, during 2% of the Martian year,” Soto says. “This would preclude life as we know it.”

索托说：“即使是地球上最极端的生命也有其局限性，我们发现，一些盐类形成的盐水可以形成火星表面40%以上的液态水，但这是有季节性的，只占火星一年内2%的时间。”。“所以，我们所知的生命是无法在这里生存的。”

So yeah, that’s a bit of a bummer. The good news is that NASA’s Perseverance rover will soon be headed to Mars, and it’ll be gathering samples of the surface and conducting experiments that could reveal whether life has ever existed on the planet.

所以，是的，有点令人沮丧。好消息是，美国宇航局的“Perseverance”号探测器不久将前往火星，它将收集火星表面的样本，并进行实验，以确定火星上是否曾存在生命。