The truth is, that I'm not sure.
I do think that the atmosphere has something to do with it.
In fact, all that O2 and N2 are probably the reason.
Let me speculate a bit.
O2 and N2 don't absorb any of the radiation, either coming or going.
If there were no greenhouse gases, then the world would be colder.
However, the CO2 and H2O do intercept infrared radiation, and re-radiate it.
That's 33C of warming.
In addition, they interact with oxygen and nitrogen, warming them, via intermolecular conduction.
W/O the GHGs, they wouldn't be all that effective in retaining heat.
There's another mechanism to consider.
The ground would warm any atmospheric gases.
What that does is distribute heat around the world.
The warmer air rises, and the cold air blows in, to be warmed by the warm ground.
When I go hang gliding, near the coast of Calif, I see that happening.
At night the ground cools off, and so does the air.
In the morning, as the sun gets high enough to warm the ground, the air over the central valley is heated and rises.
That causes the cooler air over the ocean to blow in to the valley.
There's a very clear wind profile throughout the day.
Still, to east (from the east) cold ground, early in the morning.
9-11am the wind slows and reverses direction.
12-4pm west wind picks up during the day.
5-8pm west wind slacks off as the central valley ground is no longer hot and the cool air that has blown in from the ocean no longer rises as strongly.
What that shows is that the atmosphere can have a moderating effect.
It doesn't show that GHGs keep the surface of the earth warmer, but from the science, we know that.
In addition, there is, of course, some heat from the core of the earth, although that's probably not a large fraction.
The moon has no atmosphere. So first, understand that your question is about the surfaces whereas discussions of climate are about temperature of atmosphere. On average the moon's surface is colder than earth by about 91 degrees C: -75 degrees C on the moon versus 16 degrees C on earth.
The moon is colder on average because there is no atmosphere. The surfact of the moon is not a good conductor of heat; daytime heat is not conducted to the cold night side. Once a piece of surface moves from day to night, the heat escapes to space very quickly.
On earth, even without greenhouse gasses, the heat would escape more slowly than on the moon because it has to pass through and warm the atmosphere as it escapes to space. Greenhouse gases add an additional process that slows the escape of heat to space.
colder and hotter, of course. Our atmosphere helps to moderate the extremes of our climate, just as proximity to a major body of water does to a landmass on Earth. It tends to average out the temperatures by moving the heat around, something impossible where there is no atmpsphere and no oceans.
The biggest effect though is the greenhouse gases in our atmosphere which trap some of the sun's radiant heat and make it warmer here than the moon which is at the same average distance frome the sun. The moon with no atmpsphere doesn't do that so it's just a dead body of rock in space, acting as a convenient nearby reference body. So greenhouse gases make Earth about 33C warmer than we would otherwise be.
(PS Testing homemade wine may have affected my English and typing)
The Moon is only colder than the Earth when the Sun is not illuminating it-233 degrees c,and is +123 degrees c when illuminated. Also the Moon only has trace amounts of an atmosphere which is not enough to trap any heat from the Sun.
I like crash's explanation. No hot air from Republicans. But the truth is, two reasons.
No carbon dioxide and no water vapor. You need both.
Without carbon dioxide, the water vapor would be frozen solid. Without water vapor, at least if the carbon had a partial pressure - 1.6 - 1.6no greater than that of Earth, it would not have the amplifying effect of water vapor. Water vapor and carbon dioxide are dance partners. On Earth, they are like dance partners.
Although, if the Moon had an atmosphere of 95% carbon dioxide with a pressure of 1kPa, like Mars, it would be about 10C warmer than it is now. If it had an atmosphere like Venus, its temperature would be less than 100C.
Contrary to what some of your favorite denialist sites say, if the moon had an atmosphere of nitrogen and oxygen, but no carbon dioxide, it would be no warmer than it is now, regardless of pressure. Just as much sunlight would reach the Moon's surface and just as much infra-red would escape into space as does now.
If water vapor were present on the Moon and carbon dioxide had a partial pressure of 40Pa, like on Earth, it would actually get cooler by increasing oxygen and nitrogen, because adding more oxygen and nitrogen suppress the evaporation of water. If carbon dioxide and water vapor were the only components of the atmosphere, the Moon had an ocean and the partial pressure of carbon dioxide were 40Pa, the relative humidity would be 100%. Relative humidity is less than 100% on Earth because the oxygen and nitrogen suppress the evaporation of water.
As someone who claims to be a power plant engineer, you should know that temperature and pressure are independent variables. Reversible adiabatic compression and expansion are not the only ways to change pressure. There is isothermal compression and expansion. There is also isobaric heating and cooling. After the air leave a compressor and enters the tank, it undergoes isochoric cooling, until it reaches the temperature of its surroundings.
The moon at night drops to about -153°C. During the daylight it can rise to 107°C. So it's actually both much colder AND much warmer depending on if the Sun is up or not. It's a surface of temperature extremes because it has no atmosphere to buffer the temperature. http://www.universetoday.com/19623/tempe...
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Its simple really.
After 7 years of participation in this YA global warming category I can with 95% certainty tell you the answer is , THERE ARE NO REPUBLICANS ON THE MOON..
The one thing I've learned here is that conservative voters & politicians are solely & exclusively responsible for any & all planetary warming.
No other possible explanation is even worthy of consideration.
Tjhere's no greenhouse effect, that's about 33K difference. The surface is more reflective - that's the rest of it.
Oceans soak up a LOT of sunlight.
because the moon does not have an atmosphere to help keep in the heat the sun produces when the light is reflecting on the earth
It tends to average out the temperatures by moving the heat around, something impossible where there is no atmpsphere and no oceans.
I espec ially want to read Lin Lyons explanation
Because it doesn't have as thick of an atmosphere. It's like when you wear a thick puffer jacket. It keeps you warmer than a thin jacket.
NO air on the moon/ only the lack of it, like outer space, but I dont know if it's cool or something else. Mike
The moon has no atmosphere so the greenhouse effect cannot occur resulting in a very cold place. Unlike our earth who is getting a bit too much which causes global warming.
it's not "supposedly", that's what the laws of physics say. The moon would never have the same atmosphere as earth's as it has much smaller mass and could not retain as much atmosphere.
No atmosphere
The moon's temperature is unknown since there is no way to measure the temp and if you think we landed on the moon you really are in trouble.
Do you mean the reason it GETS colder (as well as warmer)?
Maybe you could tell us the reason that the moon does not have seasons?
