Mars once had a warmer and wetter climate, with liquid water on its surface billions of years ago. However, its water has been lost to space along with its atmosphere. A NASA spacecraft called MAVEN has collected data that has enabled scientists to see this process in action, known as sputtering.
Sputtering occurs when charged particles from the solar wind strip away a planet’s atmosphere. Mars lost its global magnetic field early in its history, leaving it vulnerable to the solar wind. As its atmosphere thinned, it was no longer able to retain its water. Scientists had suspected that sputtering played a key role in this process, but never directly observed it until now.
MAVEN used three science instruments to build a 3D map of Mars’s atmosphere, showing bursts of argon gas where solar particles hit the atmosphere. The team found that sputtering is happening four times faster than predicted, and during solar storms, the rate increases even more.
Understanding sputtering can help scientists learn more about ancient Mars’s climate history and potential habitability. The findings suggest that sputtering played a major role in shaping Mars’s climate and may have made it less welcoming to life. This study provides new insights into how planets’ atmospheres are fragile and vulnerable to the harsh conditions of space.
Source: https://www.skyatnightmagazine.com/news/mars-sputtering