I like following the Hi-RISE project on Twitter and such. Hi-RISE is a pair of satellites that orbit Mars and take very high-definition photos. Often times, they find interesting features that people didn’t notice before.
Why so many dust-devils on Mars? Mars is quite different than Earth. Although it probably had water and more atmosphere in the past, it is basically a kind of cold-desert now similar to the Gobi Desert. Mars has low gravity (only 37% of Earth’s) and so most of the atmosphere on the planet and moisture have gradually left over billions of years. Also, because the magnetic field is so weak, there’s nothing to protect it from energy from the Sun, which destroyed lots of the chemicals there and now the atmosphere is extremely thin (0.6% of Earth’s).
So, due to low gravity and no protection from the Sun, Mars dried up, lost its atmosphere and become a dead world:
The only activity left on Mars are just dry, dust-storms. Amazing how entire worlds can just “die” if the conditions are wrong.