Rare active volcanoes on Mars could be causing the entire Earth to spin faster

Scientists know that Mars’ rotation has become a little faster each year, but the cause has remained a mystery. Now, a new study published in the Journal of Geophysical Research: Planets on February 18 suggests the reason may lie deep underground, where giant plumes of buoyant rock may be stirring beneath the Martian crust.

This strange plume could help explain not only how quickly Mars spins, but also how the planet’s geothermal heat persists much longer than expected, forcing scientists to rethink how tiny rocky worlds cool and disappear.

“The surface of Mars is very old and exhibits all these complex processes that are poorly understood.[es]”I think we can start to understand by combining the interior and the surface,” Bart Root, assistant professor of planetary exploration at the Delft University of Technology in the Netherlands and lead author of the study, told Live Science in an email. “The history of Mars unfolds on red soil, so understanding Mars will help us understand the solar system.”

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Mars is home to some of the largest volcanoes and mountains in the solar system. This is because, unlike Earth, Mars does not appear to have plate tectonics (the movement of tectonic plates that causes much of Earth’s volcanic activity). Instead, lava from ancient active volcanoes on Mars just sits there, piling up and building much larger structures over time. The result was the volcanic province of Tharsis, a region dotted with volcanoes that stretches 3,700 miles (6,000 kilometers) across the Earth’s surface.

In 2018, NASA sent the InSight lander to Mars to better understand its interior, which could potentially help us learn more about volcanoes. For many years, landers have studied the interior of Mars, allowing scientists to directly estimate the thickness of the Earth’s crust.

Root and his team used data from InSight to run computer simulations to test what kinds of structures could explain why volcanic regions dominate one side of Mars. These models pointed to a plume of unusually light material, or material less dense than the surrounding rock, in the mantle beneath the Tharsis region called a “negative mass anomaly.”

Researchers say this anomaly could explain why the Tharsis region became so vast and volcanic-filled.

“A negative or light mass anomaly would travel upwards and impact the Martian lithosphere, introducing melt pockets that could penetrate the crust and erupt as volcanoes,” Root said. (The lithosphere is a single, hard outer shell about 310 miles (500 km) thick.

What is the solution for spin?

The researchers then asked whether the same hidden eruptions of material could explain Mars’ strange rotational speed. Previous measurements comparing data from InSight with data from the Viking landers that explored Mars in the 1970s showed that the Martian day is shrinking by about 70 microseconds per year. This means that the planet spins slightly faster over time.

Root and his team used simulations to calculate whether this less dense material beneath Tharsis could move enough mass inside Mars to affect the planet’s rotation.

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“Some simple inside-out calculations can explain orders of magnitude in observed velocities,” Root said. “Of course, actually linking this better would require more complex modeling.”

Root compared the process to someone spinning around in their desk chair while carrying a heavy book. Pulling the book inward will make it spin faster. Mars may be doing something similar with this less dense material.

“Negative mass flowing upward means heavier stuff has to come down, and since the mass anomaly is located at the Martian equator, this means heavier mass is moving closer to the Martian equator.” [the] It has a rotating axis, which increases speed,” Root said.

These models not only hold potential solutions to some of Mars’ biggest mysteries, but also could help scientists better understand how the rocky planet cools and eventually dies. Because Mars is much smaller than Earth, researchers have long thought that Mars lost its internal heat relatively quickly. But if Mars still has enough energy to trigger deep mantle motion, that suggests the smaller world could remain active for longer than expected.

“We want to show that Mars is more interesting than we imagined,” Root said.

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