Scientists find previously unknown deposits of CO2 on Mars

Scientists find a gigantic and previously unknown deposit of CO2 at Mars’ south pole.

“We already knew there is a small perennial cap of carbon-dioxide ice on top of the water ice there, but this buried deposit has about 30 times more dry ice than previously estimated,” said Roger Phillips of Southwest Research Institute in Boulder, Colo. Phillips is deputy team leader for the Mars Reconnaissance Orbiter’s Shallow Radar instrument and lead author of the report. . . . “When you include this buried deposit, Martian carbon dioxide right now is roughly half frozen and half in the atmosphere, but at other times it can be nearly all frozen or nearly all in the atmosphere,” Phillips said.

What this discovery means is that, depending on Mars’ orbital circumstances, its atmosphere can sometimes be dense enough for liquid water to flow on its surface.