Like Earth, Mars experiences climatic variations during the course of a year because of the obliquity of its rotational axis. This leads to the annual deposition/sublimation of the CO2 ice/snow, which results in the formation of the seasonal polar caps. Similarly, these variations in temperature result in interaction between the atmosphere and the polar ice caps, which has a seasonal effect on surface features.
On Mars, however, things work a little differently. In addition to water ice, a significant percentage of the Martian polar ice caps are made up of frozen carbon dioxide (“dry ice”). Recently, an international team of scientists used data from NASA’s Mars Global Surveyor (MGS) mission to measure how the planet’s polar ice caps grow and recede annually. Their results could provide new insights into how the Martian climate varies due to seasonal change.
Back in November 2018, NASA announced that the Mars 2020 rover would land in the Jezero Crater. Jezero Crater is a geologically diverse area, with an alluvial fan of sediment deposited by an incoming river. That sediment may contain preserved ancient organic molecules, and the deposit is clearly visible in satellite images of the Crater.
But the crater holds something else that has scientists intrigued, something that doesn’t show up so clearly in visible light images: a “bathtub ring” of carbonates, which scientists think could hold fossils.
The ancient climate of Mars is a mystery to scientists. Even with all we’ve learned about Mars, it’s still difficult to explain how lakes and rivers existed. A new study shows that Martian rivers were swollen with runoff and that they flowed far later into the planet’s history than previously thought.
The question is, how did the Martian climate create these conditions?