NASA’s HiRISE camera has recently imaged sand dunes on Mars that resemble kidney beans. But these formations are not what they seem – they’re actually frozen in place by carbon dioxide frost, similar to how ice forms on Earth’s sand dunes.
The tilt of Mars’ axis plays a crucial role in determining the planet’s temperature and potential habitability. When the northern hemisphere is tilted towards the sun, it experiences warmer temperatures, while a high tilt can lead to extreme cold. This variation affects the formation of carbon dioxide frost on the sand dunes.
As CO2 ice sublimates, it turns into vapor and rises to the atmosphere, potentially creating thicker atmospheres that could have supported liquid water and life. Scientists are studying these formations to understand how Mars’ climate may have changed in the past.
Recent simulations suggest that Mars’ tilt can vary significantly over time, from minimal to extreme angles. This change affects the planet’s ability to retain a stable atmosphere, making it more or less hospitable to potential life forms. The hemisphere tilted towards the sun during warmer eras would experience long summers with atmospheric pressure high enough to sustain liquid water.
Researchers believe that Mars may have had a thicker atmosphere in the distant past, similar to Earth’s. However, its smaller size and lack of a strong magnetic field allowed it to lose this atmosphere, making the planet inhospitable to life as we know it. Further observations of these frozen sand dunes could potentially reveal clues about Mars’ potential habitability in the past.
Source: https://www.popularmechanics.com/space/moon-mars/a63434564/mars-sand-dunes-water