Most of Mars atmosphere was lost to space

​Washington: Solar wind and radiation were responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, new results from NASA have revealed.

CO2 is of interest because it is the major constituent of Mars' atmosphere and because it's an efficient greenhouse gas that can retain heat and warm the planet. "We determined that the majority of the planet's CO2 was also lost to space by sputtering.

There are other processes that can remove CO2, so this gives the minimum amount of CO2 that's been lost to space,a explained Jakosky.

Liquid water, essential for life, is not stable on Mars' surface today because the atmosphere is too cold and thin to support it.

However, evidence such as features resembling dry riverbeds and minerals that only form in the presence of liquid water indicates the ancient Martian climate was much different - warm enough for water to flow on the surface for extended periods.

There are many ways a planet can lose some of its atmosphere. For example, chemical reactions can lock gas away in surface rocks, or an atmosphere can be eroded by radiation and a stellar wind from a planet's parent star.