The iron core of Mercury is about the same size as the moon of Earth – that’s three-quarters of the planet’s diameter. Researchers say that this probably happens due to the magnetism of the Sun, and not because of the collision with the other bodies, as everyone previously thought.
Mercury is the smallest planet in the solar system, and it has a temperature of 510°C. It is placed at around 58 million km from the Sun. One day on Mercury is about 59 Earth days.
The study shows that, during the early days of the formation of the solar system, the iron grains were actually drawn in by the magnetic field of the Sun. Mercury, which is the planet that’s closest to the Sun, got the most out of the iron filings, thus proving its dense metalcore. And since the planets formed with the dust and the gas that formed the space, those planets closer to the Sun had more iron than those that were further away.
There are also other planets from outside the solar system, like K2-229 b that have a similar iron composition as Mercury. There are also others in the deep space, that orbit a star that is similar in composition to the Sun. This has made researchers even more curious: is it the evolving magnetic field of the star that makes planets have an iron-rich core?
William McDonough, the lead author of the study stated that ‘The four inner planets of our solar system—Mercury, Venus, Earth and Mars—are made up of different proportions of metal and rock. There is a gradient in which the metal content in the core drops off as the planets get farther from the Sun.’
This paper is aimed at showing that the distribution of raw materials in the early days of forming of the solar system was controlled by the magnetic field of the Sun.