The recent NASA confirmations of liquid water on Mars and the cause of a stripping atmosphere on Mars have brought a lot of attention to Mars. Since we are on simulated Mars, we have gotten a lot of questions regarding our reaction to the news.
There are three planets in the habitable zone of our Sun: Venus, Earth, and Mars. Venus is wicked close to the Sun and does not have an internal magnetic field because of its really slow rotation. So it is very hot and has a very dense atmosphere that is made up mostly of CO2, and is dramatically affected by solar winds.
An artist’s impression of how solar winds are affected by Venus’ (top) and Earth’s (lower) magnetic fields. Source: ESA
Mars isn’t that much further away from the Sun than Earth. It is at the edge of the habitable zone. It could be habitable, but it isn’t, because of its atmospheric loss cause by the Sun. The Sun can only get away with this because Mars doesn’t have an internal magnetic field. Mars has many hundreds of very small magnetic fields (indicating prior plate tectonics), but none of them have the effect of Earth’s large ...