# QuestionTemperature on the Moon?

#### mossathewriter

What would be the digit recorded by a thermometer suspended in the shade in a hit-by-sunrays site on the Moon? bearing on mind that the thermometer would be in a vacuum, since there is no air on the Moon, and that the seething temperature of the surroundings would have no effect on the thermometer, since heat does not transfer through a vacuum.

#### billslugg

A thermometer would stabilize at a temperature of the average of what it sees. Take the percentage of outer space at -457°F seen by it, the temperature of the shaded Moon surface at -280°F seen by it and the temperature of the sunlit surface at +260°F seen by it, then calculate a weighted average.

#### mossathewriter

A thermometer would stabilize at a temperature of the average of what it sees. Take the percentage of outer space at -457°F seen by it, the temperature of the shaded Moon surface at -280°F seen by it and the temperature of the sunlit surface at +260°F seen by it, then calculate a weighted average.
One centimeter above the ground and upward anywhere on the Moon, whether the site is sunlit or shaded, it is -457° F, as there is no medium through which the heat of the Moon's surface can transfer upwardly.

#### billslugg

You are correct that there is no medium to transfer heat by conduction. However, heat transfer by radiation heats any lunar soil in sunlight to +260°F. Any soil in the shade loses its heat to the open sky which is at -457°F. Any bit of soil in the shade which looks at both unshaded soil and the open sky reaches a temperature in between the two in proportion to how much of each it sees.

#### mossathewriter

You are correct that there is no medium to transfer heat by conduction. However, heat transfer by radiation heats any lunar soil in sunlight to +260°F. Any soil in the shade loses its heat to the open sky which is at -457°F. Any bit of soil in the shade which looks at both unshaded soil and the open sky reaches a temperature in between the two in proportion to how much of each it sees.
If heat transfer by radiation, why, then, the temperatures of the outer layers of all the planets of the Solar System are colder than those of the inner layers: they should be hotter as they are nearer to the sours of radiation?

#### billslugg

The outer layer of the Earth's atmosphere, the thermosphere, is very hot 900°-3,600°F . This is due to the exposure to the Sun's radiation and the fact there are so few molecules to transfer the heat to. In fact, a thermometer up there would read freezing temperatures. There would be so much radiative heat loss and so little transfer of heat from the few molecules that are there.