The interior of Mars could be the cause of the loss of the atmosphere

Changes deep in Mars' core may have caused the planet to lose its magnetic field early in its history, a new study suggests. Today, Mars is a planet with a thin atmosphere that is unable to support a substantial amount of running water on the surface, but scientists have found evidence of ancient lakes, streams and perhaps oceans that suggest different conditions. So scientists are eager to understand the presence (or absence) of water on Mars in its ancient history, in particular to understand a possible possibility of life on the Red Planet.

In particular, the researchers want to understand what could have caused the dramatic thinning of the planet's protective atmosphere. A new study has looked at changes in the planet's core that may have led to the weakening of Mars' magnetic field over time, leaving the atmosphere vulnerable to erosion.

Team work has suggested that around 4 billions of years ago inside the core, "the behavior of the molten metal, which was thought to be present, probably gave rise to a short magnetic field that was destined to vanish," wrote representatives from the University of Tokyo, where the researchers were based. The researchers simulated the conditions of the first Martian core using a sample of material expected to be found there, including iron, sulfur and hydrogen. This sample was placed between two diamonds, compressed and heated, in an attempt to replicate the immense pressures and heat found inside the core.

Credits: SA / DLR / FU Berlin; NASA MGS MOLA Science Team

Using X-ray observations and electron beams, the team tracked changes in the sample as the material was pressurized and compressed. Scientists found that the initially homogeneous Martian material separated into two liquids. "One of the iron liquids was rich in sulfur, the other rich in hydrogen, and this is the key to explaining the birth and eventually death of the magnetic field around Mars," said co-author Kei Hirose, professor at the Department of Earth and Planetary Sciences of the University of Tokyo. The experiment also showed that the less dense hydrogen liquid rose above the much denser sulfur-rich liquid. This movement caused temporary convection currents on Mars, similar to those still in existence on Earth. Scientists believe these currents generate our magnetic field. On Mars, however, the magnetic field only lasted temporarily. After the liquids parted, the study suggests, the currents ceased as there was no more activity to drive the currents.

Around the same time, light hydrogen in the atmosphere flew away into space due to the erosion of the solar wind, or the constant flow of charged particles emanating from our sun. The minor atmosphere in turn led to the eventual breakdown of water vapor (since water includes hydrogen ). As the atmosphere thinned, liquid water stopped flowing to the surface. The researchers hope that missions such as NASA's InSight lander, which is tracking seismic activity on the Red Planet, can provide further context regarding the composition of the core.

“With our findings in mind, we hope that further seismic studies on Mars will verify that the core is indeed in distinct layers as we predict, ”said Hirose. "If so, it would help us complete the story of how rocky planets, including the Earth, were formed and explain their composition."