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这个答案* gold-containing流星会导致“雨”黄金? *)(//www.hoelymoley.com/a/21109/6031)说(部分):>流星,在空间,非常非常非常* * * * * *冷。在地球大气中他们的旅行时间很短,只有几秒钟。实际融化只发生在最外层的陨石。这是不足以加热陨石的内部任何很大程度上如此。事实上,一些陨石落时发现有霜发现着陆后不久,因为他们周围的空气中的水分凝结!“非常非常* * * * * *”可能被夸大,但让我们看看他们是否可以低于水的冰点。(小行星的表面温度)(https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature)可以应用于球形物体的任意大小差不多,没有规模的推导;它应该为厘米见方工作对象以及将一个行星大小的岩石对象* *无气氛。$ $ T ^ 4 = \压裂{L_0 (1 a)}{\ε\σ16 \π2 ^}这里L_0美元是美元的总(太阳光度)(https://en.wikipedia.org/wiki/Solar_luminosity) 3.827×10 <一口> 26 < /一口> W和\σ是美元(Stefan-Boltsman常数)(https://en.wikipedia.org/wiki/Stefan-Boltzmann_constant) 5.67×10 8 <一口> < /一口> W / m <一口> 2 K < /一口> / <一口> 4 < /一口>。一美元是离太阳的距离,让我们假设流星已经接近1 AU足够长的时间(周)达到平衡温度。 $\epsilon$ is the asteroid's infra-red emissivity and a value of 0.9 is given as typical. The ~visible light average albedo $A$ of asteroids is the big variable here. They are usually pretty dark but there is a lot of variation and measurements are often based on other assumptions. I'll calculate the equilibrium temperature for a few, but as one can guess 1 minus a small number is close to 1, and after you take the fourth root, it's very close to 1! Albedo Temperature (vis) K C 0.05 282 8 0.10 278 5 0.2 270 -3 0.5 240 -33 So for a meteor to be *even barely below* the freezing point of water it would have to have an *above-average albedo*. It seems to me that after [tens of seconds to minutes](https://astronomy.stackexchange.com/a/38912/7982) there is not enough time for the transient heat pulse on the skin to do more than melt the surface, but the radiative heating from the plasma created for larger meteors can be quite intense, so they sometimes "explode" or breakup due to stress. Nonetheless the core temperatures of larger meteorites reaching the surface could very well reflect the temperature in space. So a meteorite becoming "frosty" soon after landing is plausible if it were of a higher than average albedo. **Question:** Have "frosty meteorites" ever been observed soon after landing? Are there photos? ---- Related: - [How long between the moment a meteor is first visible and the moment a meteorite hits the ground?](https://astronomy.stackexchange.com/q/38909/7982) - [How much time does it take for a meteor (shooting star) to touch the ground after its combustion?](https://astronomy.stackexchange.com/q/23615/7982) - [How complicated is the heating of meteors?](https://astronomy.stackexchange.com/q/35984/7982) - [What temperature do small meteorites have on impact](//www.hoelymoley.com/q/127/6031) there are answers posted but no temperatures... *yet!* - [Is it possible to estimate the size of a meteorite from its remains?](//www.hoelymoley.com/q/14864/6031) ---- [![Asteroid albedos: graphs of data by Wm. Robert Johnston last updated 25 March 2017](https://i.stack.imgur.com/42qhl.png)](https://i.stack.imgur.com/42qhl.png) **above:** From [Asteroid albedos: graphs of data by Wm. Robert Johnston last updated 25 March 2017](http://www.johnstonsarchive.net/astro/astalbedo.html) **below:** From NYTimes' [A 22-Million-Year Journey From the Asteroid Belt to Botswana](https://www.nytimes.com/2021/04/29/science/meteorite-botswana-asteroid.html) "A fragment of the asteroid 2018 LA, found in the Central Kalahari Game Reserve in Botswana in 2018.Credit...P. Jenniskens/SETI Institute" This is what got me thinking about this topic [![A fragment of the asteroid 2018 LA, found in the Central Kalahari Game Reserve in Botswana in 2018.Credit...P. Jenniskens/SETI Institute](https://i.stack.imgur.com/cUWcZ.png)](https://i.stack.imgur.com/cUWcZ.png) **For comparison:** from [this answer to *Who discovered “Egg Rock”? The Curiosity rover or people?*](https://space.stackexchange.com/a/24660/12102) >...Cropped section of image of "Egg Rock" from [redplanet.asu.edu/?p=21047](http://redplanet.asu.edu/?p=21047) showing the spots where Curiosity's ChemCam laser has ablated material. > >[![Egg rock on Mars showing the spots where Curiosity's ChemCam laser has ablated material.](https://i.stack.imgur.com/KJ2nK.jpg)](https://i.stack.imgur.com/KJ2nK.jpg) Spoiler alert: >! **People did!**

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\ begingroup美元你读过这吗? \ endgroup美元
- - - - - -Gimelist
2021年4月30日在26
1

\ begingroup美元 @Gimelist现在!:-) \ endgroup美元
- - - - - -uhoh
2021年4月30日在47
1

\ begingroup美元东西需要的或潮湿的陨石是着陆地点的氛围是有一个高湿度和露点的条件得到满足。任何露或霜,会形成陨石是来自大气中的水分。 \ endgroup美元
- - - - - -弗雷德
2021年4月30日11:01
\ begingroup美元 @Fred我买了我的朋友干/湿球温度计为了好玩和科学,但是很无聊,因为这里总是高湿度和两个从来没有不同。(我们都失望)看来,任何低于0 C霜冻立即,所以我认为大气中的任何水就足够了,但我想这不是真的吗?说20 C有非零的相对湿度,3 C表面不会积累任何霜(没有风,没有阳光,等…)? \ endgroup美元
- - - - - -uhoh
2021年4月30日11:07
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\ begingroup美元旋转的湿度计有很多更有趣。他们必须旋转正常运作——如果只有30到60秒。:-) \ endgroup美元
- - - - - -弗雷德
2021年4月30日在福音11:24

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