It now appears, based on new scientific research, that a larger proportion of the atmosphere of Mars was stripped away to space. This disappearance of the gases is likely to have occurred early in the red planet’s history. This finding comes from new analysis of data provided by the MAVEN satellite, which is in orbit around Mars. MAVEN (Mars Atmosphere and Volatile EvolutioN Mission) is a space probe developed by NASA designed to study the Martian atmosphere. The satellite was launched from the Atlas V launch vehicle in November 2013. The objective of the satellite is to assess how the planet’s atmosphere and water, presumed to have once been substantial, were lost over time.
Additional information about the atmosphere that once clung around Mars has been provided by samples collected by the Curiosity rover from the Martian surface. The rover, which landed on Mars in 2012 and which continues to collect samples (and will do so until at least 2020), has the goal of investigating Martian climate and geology. It is also designed to assess whether there ever were any environmental conditions favorable for microbial life.
The cross-analysis of data from the satellite and surface craft reveal that the early Martian air had a significant volume of carbon dioxide (how this is worked out is complex, but it relates to the trace presence of argon in the collected samples and the relationship between this gas and carbon dioxide). This is an important finding since the greenhouse gas would have been able to warm surface conditions sufficiently to support lifeforms like bacteria. Today around 90 percent of the atmospheric gas has been lost to space.
Interviewed by the BBC, lead researcher Bruce Jakosky from the University of Colorado in Boulder, U.S. states: “We’re in the process of tallying up what the total amount removed was, but I’m going to guess right now that the amount of atmosphere that was present was about as thick as the Earth’s atmosphere – about one or two bars of gas.”
The findings also suggests that there was probably a thick atmosphere: a shroud of gases around Mars equivalent to that which exists around Earth today. As to where it went, this was most probably due to an abrasive action of the solar wind generated from the Sun.
The new research is published in the journal Science, in a paper titled “Mars’ atmospheric history derived from upper-atmosphere measurements of 38Ar/36Ar.”
