Mars may be two-faced to its core

A recent study published in Nature suggests that Mars may have two distinct faces, both physically and internally. The Red Planet's northern hemisphere, characterized by smooth plains, contrasts sharply with the rugged, heavily cratered southern highlands. This dramatic difference extends to the planet's core, with the southern mantle being up to 200 to 400 degrees Celsius hotter than its northern counterpart. The core discrepancy, known as the Martian crustal dichotomy, has perplexed scientists for over half a century.

Researchers from the University of Arizona's Lunar and Planetary Laboratory, led by Alexander Berne, have utilized Mars's internal temperature to shed new light on the matter. By analyzing the planet's orbit and gravity field, the team discovered that the southern mantle is significantly softer than the northern mantle. This finding implies that Mars's core may be unevenly heated, with the southern half retaining heat more effectively.

This conclusion is supported by constraints on the temperature difference, which could only amount to a few hundred degrees Celsius rather than a potentially molten 1,000 degrees Celsius.

The source of this thermal anomaly remains a mystery, with theorists proposing various scenarios. One possibility is that a colossal impact excavated the northern lowlands, leaving the southern crust thick and insulated. Alternatively, convection currents beneath the southern mantle or a thick southern crust acting as a thermal blanket could explain the temperature disparity.

Regardless of the exact mechanism, the new findings suggest that Mars's southern hemisphere has been experiencing significantly warmer conditions throughout its history, potentially offering clues to the planet's ancient habitability and the fate of its water.