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    2015-1-27 10:20










    Unlike every other planet in our solar system, Earth's surface is 70% liquid water, which while useful for life, is also kind of weird, because everything we know about how and when our planet formed says Earth's surface should be bone dry.

    The story goes like this: our solar system formed from the collapse of large cloud of dust and gas. The dense blob of gas at the center ignited to form the sun, which as a young, unstable star unleashed a fierce solar wind. Over time this stream of charged particles pushed the remaining gas cloud farther and farther out, leaving only solid particles behind to clump together into rocks, planetesimals, and finally, the rocky planets of the inner solar system that we know today.

    And here's the problem :water, in the from of ice, couldn't have been one of the solid particles that stuck around before our planet, because the early inner solar system was far too hot for frozen water, and any water vapor would have been blasted away by the solar wind.

    So if Earth didn't start off with water, how did we end up with such splendid oceans? We know H20 wasn't manufactured here over the eons, because natural processes like combustion, breathing and photosynthesis create and destroy roughly equal amounts of water. And either way, the amounts in question are so miniscule that they can't account for the abundance of water on the planet.

    Since Earth's water was neither part of the original package nor manufactured here. It must have flown in from far away, on meteoroids or comets or other bodies originating in the outer solar system, where they were far enough from the Sun for frozen water to survive. The dirty ice balls that we call comets are a logical candidate for the source of our water. But were ruled out when we discovered that they are far richer in heavy hydrogen than Earth water. Heavy hydrogen has a neutron as well as a proton in is nucleus, and for every million hydrogen atoms in Earth water, about 150 are heavy ones, while typical comet water has twice that many.
    由于地球的水并非起源于此或產生于此,它肯定是從遠方流入的,從隕石或彗星、或者他外太陽系天體來。在那里,它離太陽夠遠,能讓水保持凍結。那些臟冰球,即“彗星“ 是水的來源的合適候選者之一。但已被淘汰,當我們發現,其重氫含量比地球上的水高得多。重氫的原子核中有一個中子和一個質子,地球水中,每一百萬個氫原子中就有150個是重氫,而一般彗星水是它的兩倍。

    These mismatched chemical signatures suggest that Earth's water could not have arrived on comets. It turns out that the most likely source for Earth's water is a type of meteorite called a carbonaceous chondrite." Chondrite" is just the name given to the class of stony meteoroids that most commonly strike the Earth. But only the carbonaceous chondrites contain water as well as lots of carbon, if you couldn't tell from their name.
    這些不相符的化學標志表明,地球的水不可能來自于彗星。結果證明 地球水最可能的來源是一種被稱為碳質球粒隕石的隕石。“球粒狀隕石“只是那些常襲擊地球的巖類流星體的名字。但只有碳質球粒隕石中含有水以及大量的碳,如果你沒從名字里發現的話。

    They have water in then because they formed out beyond the sun's "frost line", and what's more, their water has levels of heavy hydrogen similar to that of earth water, strongly suggesting that these earth-crashers are the source of our ice caps, clouds, rivers and oceans.
    它們含水,因為它們形成于太陽的“冰凍線“外,另外,其水中的重氫含量和地球水相似,強有力的證明了,這些地球的不速之客是我們冰蓋、云層、 河流和海洋的來源。

    And thus the water that turned our planet into a blue marble came, quite literally, out of the blue.