Has there ever been life on Mars? One clue might be to quantify how much ice (and other minerals) is hiding just below the surface of the planet, a team of researchers argued this month. “If life exists on Mars, it would be there,” they said in a press release this week. “There is no liquid water on the surface,” but otherwise “life below the surface would be shielded from radiation.”
Locating ice and minerals also has another benefit, they write in the journal Geophysical Research Letters: “to prepare for human research.” And luckily, the InSight lander (which landed in 2018) has an instrument that can help estimate the speed of seismic waves in the crust of Mars—speeds that vary depending on what rocks are present and what materials fill the pores in the rocks. rocks (which can be ice, water, gas or other mineral cements).
Here is the good news. But after running applied rock physics computer models thousands and thousands of times, researchers believe it’s unlikely that there is any layers saturated with water (or ice) in the upper 300 meters (1,000 feet) of the Martian crust. “The modeling results confirm that the upper 300 meters of Mars beneath InSight is likely composed of sediments and fractured basalts.”
The researchers came to a sad conclusion, according to Space.com: “The chances of finding Martian life in the immediate vicinity of NASA’s InSight lander are very low.”
The researchers said the subsurface around the landing zone — an equatorial site chosen especially for its flat terrain and good earthquake potential — appears loose and porous, with few ice grains between gaps in the crust… The equatorial region where InSight operates, theoretically , must be able to hold groundwater, since even there conditions are cold enough for water to freeze. But the new finding challenges scientists’ assumptions about possible ice or liquid water below the surface near InSight, whose mission is to probe the subsurface.
Although surface images show that sedimentary rocks and lava flows may lie beneath InSight, the researchers’ models have uncertainties about porosity and mineral content. InSight helps fill in some of those gaps, and its new data suggests that “uncemented material” largely fills the lander’s impact region. This suggests that water is scarce, but more data needs to be collected.
It is not yet clear how representative the InSight data is of the Martian interior as a whole, but more information may emerge from future missions. NASA is considering the Mars Life Explorer, which would drill 6 feet (2 meters) below the surface to search for possible habitable conditions. In addition, the proposed Mars Ice Mapper Mission could search for possible water reservoirs for human missions.
And of course, as the researchers note in their statement, “large ice sheets and frozen ground remain at the poles of Mars.”
