The Layers of Mars The fate of almost everything on Earth’s surface is determined by infernal engines deep below. Mars is no different. Now, thanks to an intrepid robot parked on the Martian surface by NASA in November 2018, scientists have a map of our neighboring world’s geologic abysses, the first ever made of another planet. NASA’s InSight lander has been listening to marsquakes and tracking their seismic waves as they journey through the planet. A trio of papers published Thursday in the journal Science, using data InSight has collected, reveals the red planet to be something like a colossal candy treat imagined by a ravenous deity. Its crust is split into two or three layers of volcanic chocolate. The mantle below has a surprisingly sizable and rigid toffee-like filling. And the planet’s core is surprisingly
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light — less nougaty center, more syrupy heart. Paired with recent activities at the surface by new NASA and Chinese robotic rovers, these missions highlight stark differences between our blue world and the red one next door. This survey of the Martian insides has been a long time coming. Earth’s solidbut-squishy mantle was first glimpsed in 1889, when seismic waves from a quake in Japan dove in and out of the layer before emerging in Germany. Earth’s liquid outer core was discovered in 1914, and the solid inner core was revealed in 1936. Similar measurements of the moon were made when the Apollo astronauts left seismometers on its surface. Now the same basic and foundational measurements have been made on Mars.
