A new discovery was published last July 31, which shows that the collision of asteroids with a lot of iron in their composition can generate a temporary magnetic field in the fragments.
The discovery was made by researchers at Yale University, and sheds light on the presence of traces of magnetism in metallic meteorites. The novelty brings answers to why researchers find magnetism in these meteorites — an ancient mystery in astronomy.
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In the study, conducted by Zhongtian Zhang and David Bercovici, published in the journal Proceedings of the National Academy of Sciences, simulations were done by computers in order to analyze collisions between asteroids.
Learn more about asteroid collision studies
The researchers noticed that, after the collision and fragmentation of two ferrous asteroids, some pieces form a cold inner core, surrounded by hotter rock.
This thermal transfer process, together with the constant movement, would be enough to activate a dynamo.
Thus, a magnetic field is generated that could last for millions of years. And that may be why astronomers detect magnetism regardless of the time after the collision.
(Image: publicity)
The discovery revolutionizes the understanding of the formation and evolution of metallic asteroids and meteorites.
Furthermore, it explains why some pieces of meteorites found on Earth have a magnetic field — like the case of VAT, which was a mystery until now.
Understand what a dynamo is
Above, we talked a little about the concept of a dynamo – which is what causes the magnetic current in meteorites and asteroids.
In reality, a dynamo is nothing more than a generator of electricity—it transforms the energy mechanics into electrical.
Despite being a device, it is based on the electromagnetism of something that revolves around a magnetic field. The variation of this field generates electric current.
In the case of asteroids, this effect occurs in the collision of rocks, melting a layer near the surface, which can lead to heating of the core.
Thus, lighter elements evaporate and go towards the surface, which cools the surroundings - this creates a convection movement, similar to that of an artificially manufactured dynamo.
