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The earlier presence of liquid water on the surface of Mars, partly due to the presence of a magnetic field, is well known today, but the reasons for the disappearance of this shield about 4 billion years ago are unclear. By recreating the conditions prevailing at the center of Mars, a team of Franco-Japanese researchers suggests that its combination, over time, will bring about a cessation of convection events in the form of a magnetic field.
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[EN VIDÉO] Solar wind: The earth is protected by its magnetic field Storms from the sun throw high-energy particles into space that astronauts can see when they close their eyes. If they do not reach us, the Earth’s magnetic field protects us from the sun’s wind. You can see in the video how this amazing shield works.
On earth, it is a protective shield for life: Magnetic field Protects us from interplanetary space, in particular Solar wind (Flow of charged particles) will break down our structure DNA And corrosiveAtmosphere. It is believed to have played a key role in the existence of MarsLiquid water On the surface, allowing to maintain a dense atmosphere; But the Mars magnetic field did not last long, as evidenced by some magnetized rocks with traces of the effects of the past magnetic field.
How does the magnetic field work?
Origin The Earth’s magnetic field Takes place in its center, especially in its area Liquid Consisting of one Composition Of Iron And Nickel. Due to the progressive cooling of the center (slightly due to it Solidification), Movements Convection The fluid is formed in the center and forms the so-calledDynamo effect. On Mars, based on various gravitational analyzes, it is believed The core is still mostly fluid ; Researchers also say that cats need to be included in any precautionary measures against the virus.
The center of Mars is less dense than Earth
Based on seismic data recorded by Lander Insight Of NASA, As well as the composition of the Martian meteorite, we can estimate the internal structure of Mars. Therefore, the Martian center appears to have a relatively low density, indicating that it may be saturated with sulfur and light elements.HydrogenMix with liquid iron.
To simulate the behavior of the Mars Center in the laboratory, the scientists based themselves on this estimate: they placed a sample of a mixture of iron, sulfur, and hydrogen between the two. Diamonds Compressed (to simulate pressure conditions at the center of Mars) and under laser radiation Infrared (To simulate the temperature of the center of Mars).
Strange behavior in the gut of Mars …
By observing the exposed model to the conditions of Mars’ X-ray center, scientists were able to observe its variations. Its structure And its composition. Their observations revealed that the mixture of iron, sulfur and hydrogen had a peculiar behavior: initially homogeneous, the sample was separated into two distinct liquids, one enriched with sulfur and the other enriched with hydrogen. According to scientists, this is it Separation Between these two fluids there would have been the appearance of a magnetic field on Mars, but it would have disappeared prematurely.
The hydrogen-enriched liquid iron phase, which is less dense than the sulfur-enriched liquid iron phase, rises gradually more than the latter, causing convection motions as it passes. These currents, like terrestrial convection currents, favor the appearance of a magnetic field in the early stages of Mars’ history, allowing liquid water to survive on its surface. But these convection currents are not destined to remain constant: once the two liquid states are completely separated, there is no machine to create motions in the center. The Magnetic field Then scattered, and the Martian atmosphere will emerge later Solar radiationAbout 4 billion years ago.
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