Exploratour - The Atmosphere of Mars
Warm and Cold
Warm and cold fronts may be more extreme on Mars than on the Earth because of the greenhouse effect. Usually the greenhouse effect helps a planet maintain an even temperature, especially as day turns to night. (Without the greenhouse effect, and an atmosphere, temperatures swing from 50 degrees to -50 degrees, as they do on the Moon).
As shown in the diagram, molecules serve as a trap of energy by absorbing energy from space, and re-sending the energy back into the atmosphere. A photon of energy can enter, but cannot easily find its way out again, somewhat like a pinball in a pinball machine. Thus molecules can keep an atmosphere warm long after the Sun has gone away.
When the atmosphere is thin, the way the atmosphere of Mars is, the greenhouse effect is reduced. It is hard to know now what this means in the atmosphere of Mars. More information from the atmosphere of Mars would help scientists learn more about what a reduced greenhouse effect means for the weather of Mars.