NASA’s InSight lander has solved a 50-year-old mystery about Mars, revealing that ancient internal processes created the planet’s “Martian dichotomy” – the divide between its two distinct halves. The data collected by the lander suggests that the southern highlands are hotter and have thicker crust than the northern lowlands due to tectonic activity that occurred in the early days of the solar system.
For decades, researchers have known that Mars is split into two main areas: the northern lowlands covering about two-thirds of the planet’s surface, and the southern highlands with an average elevation roughly 3 miles higher than the north. The cause of this planetary imbalance has been a topic of debate among scientists, with two main theories: an unknown process within the planet’s interior or a massive collision with a moon-size object.
However, new research published in Geophysical Research Letters suggests that ancient internal processes are to blame for the Martian dichotomy. By analyzing data from InSight, researchers compared seismic waves from marsquakes at two sites on either side of the divide and found that those in the southern highlands lost energy more quickly. This is consistent with the idea that the molten rock beneath the southern highlands is hotter than in the north.
The team proposes that this temperature difference can be explained by ancient tectonic activity, which was then frozen in place as the planet’s moving plates stopped moving and formed a “stagnant lid” on the molten interior. This scenario would also explain why the crust is thicker in the southern highlands.
While this study provides an important new piece of evidence, it may not be enough to conclusively answer the question of what caused the Martian dichotomy. Further research, including more marsquake data and detailed models of Mars’ formation, will be needed to fully understand the planet’s history.
Source: https://www.livescience.com/space/mars/marsquakes-may-solve-50-year-old-mystery-about-the-red-planet