Mars has a porous crust, says NASA study

Washington : Mars's crust is not as dense as previously thought and a lower density likely means that at least part of the Red Planet's crust is relatively porous, says a new NASA study.

The findings, published in the journal Geophysical Research Letters, provide researchers clue that could help them better understand the interior structure and evolution of Mars.

The researchers mapped the density of the Martian crust, estimating the average density is 2,582 kgs per metre cubed. That's comparable to the average density of the lunar crust. Typically, Mars's crust has been considered at least as dense as Earth's oceanic crust, which is about 2,900 kgs per metre cubed.

The new value is derived from Mars's gravity field, a global model that can be extracted from satellite tracking data using sophisticated mathematical tools.

Previous estimates relied more heavily on studies of the composition of Mars's soil and rocks. Goossens and colleagues started with the same data used for an existing gravity model but put a new twist on it by coming up with a different constraint and applying it to obtain the new solution.

A constraint compensates for the fact that even the best data sets can't capture every last detail. Instead of taking the standard approach, known to those in the field as the Kaula constraint, the team created a constraint that considers the accurate measurements of Mars's elevation changes, or topography.