Insight deep into Mars
Geophysicists have been using “marsquakes” to figure out the depth and structure of the Martian interior, resulting in the first interior map of another planet. It shows that Mars is markedly different to Earth, with a warm and gooey core much bigger than our own. These insights were gleaned by the Insight lander, a NASA mission that touched down on the planet in 2018. The mission’s aim: to understand the formation, evolution and composition of the entire planet.
One of its jobs is to use its ultra-sensitive seismometer to measure marsquakes – so far, it has recorded 733. Three research teams have now used the seismological data from the 35 strongest quakes to reveal the structure of Mars in Science.
One study mapped the Martian mantle, which extends 1,560km below the surface; this mantle likely only has only one rocky layer, rather than Earth’s two. Another team used the data to estimate the thickness of the Martian crust for the first time, finding that it’s much thinner than previously thought.
The final study peered right down to the core to find that it has a radius of nearly 1,830km, beginning about halfway between the surface and the centre of the planet. This is much bigger than Earth’s core. The study also confirms that the Martian core is molten, even at the centre; in contrast, Earth has a molten outer core and a solid inner core.