It’s been common knowledge in the scientific community for some time that Mars does not have a magnetic field with no clear explanation as to why this might be given its many similarities in size and structure to Earth. Recently, however, new research may have discovered what might have caused the planet to lose its poles.
Science News reports on a new theory on why Mars’ core may have ceased convection, resulting in its notable lack of magnetic field. Strangely enough, planetary scientist Joseph O’Rourke thinks water might be to blame.
Despite its numerous life-sustaining properties, Martian water may have spelled doom for the planet after a fashion. According to Professor O’Rourke’s theory, the water molecules trapped within the planet may have split apart at one point, leaving hydrogen and oxygen. These hydrogen molecules could have moved into the mantle layer of the planet, surrounding Mars’ core and preventing convection from taking place ever again.
In simplest terms, convection involves the movement of materials beneath a planet’s crust, with denser mantle materials being pulled towards the core while lighter core materials are pulled into the mantle. Because of the types of materials moved during this process (iron, in particular), this process is thought to create the beneficial magnetic field in rocky planets, including Earth.
However, an excess amount of hydrogen within Mars could make this process challenging to carry out. Hydrogen is the smallest element in the known universe, making it extremely light. With a buildup of hydrogen surrounding Mars’ core as is thought to have occurred, denser materials would not be able to move freely through what is essentially a barrier. Because of this, a charge cannot be carried through convection, meaning a magnetic field cannot be generated any longer.
The worst part is that Mars may have done all of this to itself. O’Rourke theorizes that the water in question came from minerals trapped close to the planet’s core, the extreme heat and pressure causing the molecules to separate in the first place. While the oxygen could bond with other materials and rise into the mantle, the hydrogen would most efficiently bind with itself, forming the suffocating barrier that would kill the planet’s core.
While this theory is somewhat promising, there are a few things that need to be squared. For one, the minerals in the crust of Mars (olivine) do not hold water very well. At the same time, olivine is known to transform into the water-retaining minerals wadsleyite and ringwoodite when significant pressure is applied (such as from a planet’s extreme gravity). And, while the mineral bridgmanite might act as a water-repellent buffer for a time, O’Rourke believes this mineral would have deteriorated overtime, allowing the hydrogen to move closer to the core.
Ultimately, the best way to confirm this or any other theory would be more extensive Martian research.
