(ORDO NEWS) — Scientists have long known that the surface of Mars once had oceans, thanks in large part to the presence of a protective magnetic field.
However, this magnetic field has disappeared, and in a new study, astronomers have attempted to explain the reason for the disappearance.
The researchers recreated the conditions that were maintained in the core of Mars billions of years ago, and found that the behavior of the molten metal, presumably the main material of the core, could give rise to a magnetic field, which after a short existence gradually disappeared.
“The Earth‘s magnetic field is formed by giant convection currents of molten metals flowing in its core. Magnetic fields on other planets work in a similar way, said Prof. Kei Hirose, head of the new study, from the Department of Earth and Planetary Sciences at the University of Tokyo, Japan.
“Although we still don’t know exactly what the composition of the core of Mars is, previous analyzes of the meteorite substance suggest that it consisted of molten iron enriched with sulfur.
What’s more, new seismic data from NASA‘s InSight Mars probe tells us that the core of Mars is actually larger and less dense than previously thought. This, in turn, indicates that there are additional light elements, such as hydrogen, in the core.
These experiments used a diamond anvil cell, in which the sample is compressed to achieve gigantic pressures between two diamonds, and lasers, which allow the temperature to be raised to very high values for a short time.
The researchers selected a core composition based on the Fe-SH system and subjected it to compression in a diamond anvil cell while being heated by lasers. As a result, it was found that under the experimental conditions, the system was separated into two immiscible liquids: iron enriched with sulfur and iron enriched with hydrogen.
The lighter liquid enriched with hydrogen showed a tendency to float with the formation of convection currents.
According to the authors, it is precisely such convection flows of liquid iron in the core of ancient Mars that could lead to the formation of a short-term magnetic field, which allowed water to exist for some time in liquid form on the surface of the planet.
After the completion of the stratification of fluids in the core, the convection currents dried up, and the magnetic disappeared, according to Hirose and his group.
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