研究发现，火星上有两种水，它们可能来自不同的起源

An analysis of Martian meteorites shows that there are at least two different types of water contained in reservoirs on Mars, suggesting that the planet did not form in a similar way to Earth and may have obtained its hydrogen from outside forces.

对火星陨石的分析表明，火星上的水库中至少含有两种不同类型的水，这表明火星的形成方式与地球不同，可能是从外力中获得了氢。

The Red Planet is composed of a core, mantle, crust, and atmosphere, which means that it evolved through geological processes much like Earth. Previous theories suggested that Mars also may have once had a global magma ocean, however, the planet lacks evidence of ever having plate tectonics and, without them, the crust would have served as a “physicochemical barrier” between the atmosphere and geological fluids contained within the mantle. Ancient river valleys and deltas suggest that Mars has a watery past, but today the atmosphere is too thin for liquid water to exist on the surface, according to NASA. Rather, it is held in ice form below the planet’s surface in the polar regions.

这颗红色行星由地核、地幔、地壳和大气组成，这意味着它的演化经历了与地球相似的地质过程。先前的理论认为，火星也可能曾经有过一个全球岩浆海洋，然而，火星缺乏板块构造存在的证据，如果没有板块构造，地壳将成为大气和地幔内地质流体之间的“物理化学屏障”。据美国宇航局的说法，古老的河谷和三角洲表明火星有一个多水的过去，但如今的大气层太薄，液态水不可能存在于火星表面。相反，它是以冰的形式存在于极地的行星表面之下。

But where this water came from – and how Mars came to be – has long been a mystery to scientists.

但是，这些水是从哪里来的，以及火星是如何形成的，对科学家来说，这一直是个谜。

That’s where researchers at the University of Arizona come in. To reconstruct the water history and the planet’s origin, scientists chemically analyzed two Martian meteorites known to have interacted with fluids contained below the surface of the planet: Northwest Africa 7034, or Black Beauty, and Allan Hills 84001. Specifically, two types, or isotypes, of hydrogen were found to exist within their contains. One form contained only a proton in its nucleus, which is known as “light hydrogen,” and the second both a proton and a neutron, also known as deuterium or “heavy hydrogen.”

亚利桑那大学的研究人员就是冲这个来的。为了重建水的历史和地球的起源，科学家们对两颗火星陨石进行了化学分析，这两颗陨石已知曾与地球表面以下的流体发生过相互作用：非洲西北部7034号，或称“黑色之美”，以及艾伦·希尔斯84001号。具体地说，在他们的容器中发现了两种类型的氢，或者说是同类型的氢。一种形态的原子核中只含有一个质子，即所谓的“轻氢”，另一种形态的原子核中同时含有一个质子和一个中子，也称为氘或“重氢”。

On Earth, water held within rocks is unfractionated, meaning that it does not deviate much from ocean water. On the other hand, previous meteorite analyses have suggested that Mars is heavily fractioned and varies greatly.

在这颗星球上，岩石中的水是不分馏的，这意味着它与海水的差别不大。另一方面，之前的陨石分析表明，火星经历过严重分裂和很大的变化。

"The prevailing hypothesis before we started this work was that the interior of Mars was more Earthlike and unfractionated, and so the variability in hydrogen isotope ratios within Martian samples was due to either terrestrial contamination or atmospheric implantation as it made its way off Mars," said Jessica Barns, assistant professor of planetary sciences at the University of Arizona Lunar and Planetary Laboratory, in a statement.

杰西卡·巴恩斯说：“在我们开始这项工作之前，普遍的假设是，火星内部更像地球，也更不实际，因此火星样品中氢同位素比值的变化是由于火星离开火星时受到地球污染或大气注入所致。”，亚利桑那大学月球和行星实验室行星科学助理教授在一份声明中说。

Isotopic ratios from the meteorites fell halfway between those found on Earth and others seen in Mars’ atmosphere, an interesting discovery considering that Mars' atmosphere is being fractionated but the crust is staying roughly the same throughout the planet’s geological history. Further analysis found that there are also two different types of Martian volcanic rocks – enriched shergottites and depleted shergottites – that both contain water with different hydrogen isotope ratios.

陨石的同位素比值介于地球上发现的陨石和火星大气中发现的陨石之间，这是一个有趣的发现，考虑到火星大气正在被分馏，但地壳在整个地球的地质历史中基本保持不变。进一步分析发现，火星上还有两种不同类型的火山岩——丰富和贫瘠的钙铁矿含量——它们都含有不同氢同位素比率的水。

The two different types of hydrogen, which are described in Nature Geoscience, suggest that Mars has at least two different types of water that likely came from different sources. Over the planet's several-billion-year-history, two celestial objects with different water contents may have collided and never have mixed.

《自然地球科学》中描述的两种不同类型的氢，表明火星至少有两种不同类型的水，可能来自不同的来源。在火星数十亿年的历史中，两个不同含水量的天体可能发生了碰撞，但从未混合过。