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可能一个冰冷/极度寒冷的小行星或彗星罢工和冷却地球吗?

这显然是一个假想的问题,但是这似乎是可计算的(我没有这样做,不幸的是数学能力)。注:我没有深入了解彗星小行星/流星/甚至任何空间对象,所以请纠正我如果我犯了任何错误。同时,请回答这个问题考虑地球的当前状态,而不是一个地球过热。

一些命题:

小行星或彗星是相当大的,冷的核心,是由材料具有高的热容
小行星或彗星“罢工”地球速度低
小行星或彗星撞击海洋

回答

热力学不= = -对气溶胶的影响给出一个好的答案。其他人观察到影响地球补充能量。我只是想看看能源预算。太阳的转储(173兆瓦)[1]在地上,没完没了。现在,小行星(热容)[2]的10美元^ {18}- 10 ^ {24}J / K美元,根据大小。请注意,petawatt是10美元^ {15}J / s $。还要注意,太阳转储10美元^ {18}W美元地球上每5.8秒左右。现在,让我们想象一下我们发现小行星星际空间漂浮在一个寒冷的3 K(或冷或暖……确切的数字并不重要)。让我们进一步假设我们可以在地球和查克土地没有任何重大的能源(我们使用一个外星人拖拉机梁轻轻低表面)。这颗小行星将“酷”地球通过加热本身。 So...how much cooling should we expect? Instead of pretending that the earth is a lone ice box floating in space, and calculating what happens when we drop a large ice cube into it, I think it's more useful to simply ask: "How quickly will the sun melt our ice cube?" The sun will contribute enough energy to warm the asteroid by 1 K every 6s or so, for a small asteroid. To raise the asteroid from 3 K to earth mean surface temperature of 288 K will take somewhat less than 1800 s, or about 30 minutes. That's about how long an ice cube would last in a chilled beverage on a not particularly warm day. Now, that is roughly equivalent to turning off the sun for 30 minutes. That would have a noticeable effect on global weather, but I doubt it would remain noticeable even a few days after. Over the course of a year, this blip would amount to a solar energy reduction of 0.005%. Hardly enough to detect in the climate record. Of course, we picked the smallest asteroid for the initial calculation. If you go towards the large end, you can crank up all these numbers by a factor of a million, more or less. Ceres, for instance, would suck up about 5000% of the sun's annual energy sent to earth. That's 50 years of solar energy, and obviously a significant impact. Given that it's round, we can debate whether Ceres counts as an "asteroid" or not. [Nysa][3] is more "asteroid-shaped", but only has about 100x the heat capacity of our initial calculations. So, a solar dip of 0.5% over the course of a year might be enough to notice, but likely not enough to cause attributable long-term climate effects (given that the Milankovitch cycles produce larger variance). Note that if you start with a more typical asteroid temperature of about 200 K, you would reduce all the energy budget numbers to about 1/3 of their value (meaning, the smallest ice cube would melt in ~10 minutes). [1]: https://phys.org/news/2011-10-vast-amounts-solar-energy-earth.html [2]: https://www.lpi.usra.edu/meetings/lpsc2012/pdf/2626.pdf [3]: https://en.wikipedia.org/wiki/44_Nysa

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