Moon Temperatures

Temperature Variations on the Moon

The heating process would not be evenly distributed and when the +280 degrees Celsius is reached the surface can’t get hotter due to the natural loss of heat to layers beneath the surface and to radiation leaving the surface.  [cseligman]On the Moon, the temperature rises very quickly in the morning because...very little sunlight is reflected away ... When the Sun goes down about two weeks later, temperatures drop just as quickly, reaching sub-zero temperatures within a very few hours[cseligman]

I have added notes in red to the following answer to a question on spaceanswers.com.

[spaceanswers: Megan Whewell]Over the course of a full lunar day and night, the temperature on the Moon can vary wildly, from around +200 to -200 degrees Celsius (+392 to -328 degrees Fahrenheit), so it’s natural to wonder how lunar astronauts survived this huge temperature variation. The first thing to know is that all trips onto the Moon’s surface were carefully planned for lunar dawn, to ensure the surface hadn’t had time to heat up fully to its daytime temperature. It is also important to think about how heat can be transferred to astronauts on the lunar surface. There are three ways heat can transfer and only two are possible on the Moon. The first is radiation, both directly from the Sun and from the Sun’s reflection on the surface. The astronauts’ spacesuits were designed to reflect almost 90% of the light that reaches it, so very little heat would have transferred to the astronauts [That does mean that all the light is continuously reflected. Stand out in the street or backyard on a hot summer's day, wearing all white (even a white hat) and see how long it takes before you become uncomfortably hot. If a garment could reflect 90% of all light that strikes it, then there would be no need for personal survival packs such as the PLISS worn by astronauts].

The second is by conduction from the direct contact their feet had with the surface. This is also an ineffective process as regolith on the lunar surface doesn’t conduct heat well [that means the reflected light would have no effect on the astronauts as well and no effect on lighting shadowed areas] and the astronauts’ boots were insulated, slowing down conduction even further. This shows that even though huge temperature variations occur on the Moon, lunar astronauts were never actually exposed to them [Again this is not good science, it is opinion. The heat generated by the Sun's light striking the astronaut's suit, boots and helmet, would quickly rise to dangerous levels, that is why they are shown wearing a survival pack. The astronauts are seen wearing spacesuits that soon become blacken with 'regolith' dust. That being the case, the fabric would be absorbing much more than 10% of radiated heat] [Answered by Megan Whewell, Education Team Presenter for the National Space Centre].

References

http://cseligman.com/text/planets/atmosphere.htm

Heiken et al. Lunar Sourcebook: A User's Guide to the Moon. Cambridge: University of Cambridge Press, 1991.

http://www.asi.org/adb/m/03/05/average-temperatures.html

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