Recent measurements from NASA’s insight mission show that Mars’ core is less dense than previously believed planetary scientists. This shows that Mars has never developed a solid inner core at the earliest time in its history. in New research Published in the journal Geophysical Research BookResearchers at the University of Texas and elsewhere were hoping to understand the impact of this lack of a solid inner core.
Computer simulation of the unilateral magnetic field of early Mars. Image credits: Ankit Barik/Johns Hopkins University.
“Like Earth, Mars once had a strong magnetic field that protected the thick atmosphere from the solar wind,” said Dr. Chi Yang, a colleague at the University of Texas.
“But now only the magnetic imprint remains. But with a long, confused scientist, this imprint appears most strongly in the southern half of the red planet.”
The team’s new research will help explain the one-sided traces. We present evidence that the planet’s magnetic field covers only the southern half.
“The resulting biased magnetic field will match the traces we saw today,” Dr. Yang said.
“It will also make the Earth’s magnetic field that covers the entire Earth different from the Earth’s magnetic field.”
“If Mars’ inner core is liquid, a one-sided magnetic field can be generated.”
“The logic here is that it’s much easier to generate a hemispherical (one-sided) magnetic field because there is no solid inner core.”
“It could have influenced the ancient dynamos on Mars and perhaps could have maintained the atmosphere.”
In this study, researchers used computer simulations to model this scenario.
Until now, most early Mars studies relied on magnetic field models that gave the red planet an inner nucleus like Earth surrounded by solid, molten iron.
Scientists were urged to try to simulate a full liquid core after insights discovered that Mars’ core is made up of lighter than expected elements.
“That means there’s a very high chance that it’s melting because the core melts differently than Earth’s,” said Sabin Stanley, a professor at Johns Hopkins University.
“If Mars’ core was melting now, it would almost certainly have melted 4 billion years ago when it was known that Mars’ magnetic field was active.”
To test the idea, the author prepared an early Mars simulation with a liquid core and ran it dozens of times on a supercomputer.
With each run they made the northern half of the mantle planet a little hotter than the south.
Eventually, the temperature difference between the hotter mantle in the north and the colder mantle in the south began to escape from the core and only release at the southern tip of the planet.
The escape heat channeled in such a way was active enough to drive the dynamos and generate a powerful magnetic field focused on the Southern Hemisphere.
Planetary dynamos are self-supporting mechanisms that generate magnetic fields, usually through the movement of molten metal cores.
“We didn’t know if we’d explain the magnetic field, so it’s exciting to see that Mars’ interiors can create (single) hemispherical magnetic fields with an internal structure that fits insights as well as today,” Professor Stanley said.
This finding provides a compelling alternative theory for common assumptions that affect obliterating evidence of magnetic field elimination across rocky planets in the Northern Hemisphere.
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C. Yang et al. 2025. Mars hemispherical magnetic field from a full sphere dynamo. Geophysical Research Book 52(3): E2024GL113926; doi: 10.1029/2024GL113926
Source: www.sci.news
