Meteorites from Mars help scientists understand the red planet’s interior

A Martian meteorite in cross-polarized light. This meteorite is dominated by the mineral olivine. Each grain is about half a millimeter across. James Day

Of the more than 74,000 known meteorites – rocks that fall to Earth from asteroids or planets colliding together – only 385 or so stones came from the planet Mars.

It’s not that hard for scientists to work out that these meteorites come from Mars. Various landers and rovers have been exploring Mars’ surface for decades. Some of the early missions – the Viking landers – had the equipment to measure the composition of the planet’s atmosphere. Scientists have shown that you can see this unique Martian atmospheric composition reflected in some of these meteorites.