A new study differs in the prevailing hypothesis on why Mercury has a significant core relative to its mantle. Scientists believed for decades during the formation of our solar system that hit-and-run collisions with other bodies blew away much of Mercury’s rocky mantle and left the big, dense metal core inside. But according to new research, collisions is not responsible, but the sun’s magnetism is.
Takashi Yoshizaki from Tohoku University and William McDonough, a professor of geology at the University of Maryland, developed a model, and this model shows that the mass, density, the distance from the sun’s magnetic field influences iron content of a rocky planet’s core. On July 2, 2021, the paper describing the model was published in the journal Progress in Earth and Planetary Science.
According to McDonough, “The four inner planets of our solar system—Mercury, Venus, Earth, and Mars—are made up of different proportions of metal and rock. A gradient in which the metal content in the core drops off as the planets get farther from the sun. Our paper explains how this happened by showing that the distribution of raw materials in the early forming solar system was controlled by the sun’s magnetic field.”
According to McDonough’s new model, during the early formation of the solar system, when the young sun was surrounded by a swirling cloud of gas and dust, grains of iron was drawn toward the centre by the sun’s magnetic field. When the planet began to form from clumps of that gas and dust, planets closer to the sun include more iron into their cores than those farther away.
The researcher found out that the proportion and density of iron in a rocky planet’s core during planetary formation connect with the strength of the magnetic field around the sun. The new study suggests that to describe the composition of rocky planets, magnetism should be factored into future attempts. For potential support of life, the composition of a planet’s core is essential. McDonough determined by using existing models of planetary formation the speed at which dust and gas were pulled into the centre of the solar system during its formation.