Difference between revisions of "Talk:Lunar Temperature"
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* Shouldn't we mention that there is no general temperature for an area the size of a square mile on Luna as there would be on Earth. The temperatures in a particular area are not averaged out by convection of the atmosphere on Luna which has practically none. So, in a little shaded area near the equator could be nearly as cold as space if protected from heat radiation of the surrounding area. Likewise a surface normal to incoming sunlight could reach the same radiative equilibrium temperature as a flat spot at noon on the equator. Also the radiative equilibrium temperature depends on color. The lunar surface is reasonably well approximated by neutral grey tending toward black body black. | * Shouldn't we mention that there is no general temperature for an area the size of a square mile on Luna as there would be on Earth. The temperatures in a particular area are not averaged out by convection of the atmosphere on Luna which has practically none. So, in a little shaded area near the equator could be nearly as cold as space if protected from heat radiation of the surrounding area. Likewise a surface normal to incoming sunlight could reach the same radiative equilibrium temperature as a flat spot at noon on the equator. Also the radiative equilibrium temperature depends on color. The lunar surface is reasonably well approximated by neutral grey tending toward black body black. | ||
* Since there have been published comments about how difficult it is to deal with the intense cold of shaded craters at the lunar, shouldn't we mention that the space program has had considerable experience with such temperatures in the shade of the ISS and is in a position to get more experience with reasonable experimental effort. The cold mass of rock and dirt at a crater bottom is something new, but the robot foot that contacts that crater won't get colder than temperatures that we have already dealt with. An insulated boot could limit heat flow by conduction handily, and a couple of layers of shiny metal foil with vacuum between could put quite low limits on radiative heat loss.--[[User:Farred|Farred]] 09:19, 8 October 2009 (UTC) | * Since there have been published comments about how difficult it is to deal with the intense cold of shaded craters at the lunar, shouldn't we mention that the space program has had considerable experience with such temperatures in the shade of the ISS and is in a position to get more experience with reasonable experimental effort. The cold mass of rock and dirt at a crater bottom is something new, but the robot foot that contacts that crater won't get colder than temperatures that we have already dealt with. An insulated boot could limit heat flow by conduction handily, and a couple of layers of shiny metal foil with vacuum between could put quite low limits on radiative heat loss.--[[User:Farred|Farred]] 09:19, 8 October 2009 (UTC) | ||
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Latest revision as of 01:38, 10 August 2016
Some items still missing:
- what's the right value for the average emissivity (1 - reflectivity) - i.e. what fraction of incoming sunlight is reflected by the surface, rather than absorbed?
- because of orbital dynamics the solar constant varies - what is the range and what effect does this have on temperatures (seasonality?)
- how low does the temperature drop during eclipses of the sun by the Earth?
- what is the actual night-time profile?
- what is the actual depth profile?
Apsmith 12:24, 14 June 2007 (UTC)
- Arthur, the term used is Albedo, rather than reflectivity.Charles F. Radley 13:40, 14 June 2007 (UTC)
Temperature Concerns for Development
- Shouldn't we mention that there is no general temperature for an area the size of a square mile on Luna as there would be on Earth. The temperatures in a particular area are not averaged out by convection of the atmosphere on Luna which has practically none. So, in a little shaded area near the equator could be nearly as cold as space if protected from heat radiation of the surrounding area. Likewise a surface normal to incoming sunlight could reach the same radiative equilibrium temperature as a flat spot at noon on the equator. Also the radiative equilibrium temperature depends on color. The lunar surface is reasonably well approximated by neutral grey tending toward black body black.
- Since there have been published comments about how difficult it is to deal with the intense cold of shaded craters at the lunar, shouldn't we mention that the space program has had considerable experience with such temperatures in the shade of the ISS and is in a position to get more experience with reasonable experimental effort. The cold mass of rock and dirt at a crater bottom is something new, but the robot foot that contacts that crater won't get colder than temperatures that we have already dealt with. An insulated boot could limit heat flow by conduction handily, and a couple of layers of shiny metal foil with vacuum between could put quite low limits on radiative heat loss.--Farred 09:19, 8 October 2009 (UTC)
