Average day and night temperature on Mars
The averaged temperature on Mars (about -63°C) is actually considerably lower than the one on Earth (+15°C). But the variation of temperature along the seasons are really important. The gradient of temperature between the dayside and the nightside is also important. The temperature can be:
- +27°C during the day
- -133°C during the night
This is mainly due to the fact that the greenhouse effect on Mars is weak and that the Martian soil stores very few energy. Temperature also fluctuate with the amount of dust in the atmosphere of Mars.
Polar ice caps on Mars (composition)
Such cold conditions mean that it is no surprise that one can see ice caps on both poles, even with the smallest telescopes. But this dry ice on Mars mainly consists of carbon dioxide and not water as on Earth. This carbon dioxide ice comes from the atmosphere and freezes in winter as the solidification of the carbon dioxide is -125°C.
The size of the polar caps varies according to the season:
- In summer, the dry ice partly sublimates, i.e. the ice evaporates directly to gas without passing through a liquid stage.
- At the height of southern winter, the pressure can sink by as much as 30 % since up to one third of the carbon dioxide in the atmosphere can freeze. Such abrupt changes in the atmospheric pressure can lead to vast plains covered with frost.