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Earth ate a Mercury-like body early in its history, study finds
From phys.org:
...
Without that magnetic field, there would be no shield to protect us from the onslaught of radiation constantly bombarding Earth from space, making the existence of life as we know it impossible, scientists say.
...
Our planet is thought to have formed from small rocky bodies like the ones in the asteroid belt today, study co-author Bernard Wood, a geochemist at the University of Oxford, said in an interview. It's a theory that fits quite well with what's been studied on Earth, though it's not a perfect fit, he said.
"That sort of roughly works, but there are all kinds of little questions that don't quite work," Wood said, "and one of them is, what is the energy source that drives the Earth's magnetic field?"
Here's the problem. To drive Earth's magnetic field, you need radioactive elements like potassium, thorium or uranium - elements that give off heat as they decay - to also be in the planet's churning iron core. Those elements love getting together with oxygen, making oxides - but oxides are really light and would float toward the planet's surface; they wouldn't be heavy enough to stay in the core. These elements also hate getting together with iron.
more ...
Without that magnetic field, there would be no shield to protect us from the onslaught of radiation constantly bombarding Earth from space, making the existence of life as we know it impossible, scientists say.
...
Our planet is thought to have formed from small rocky bodies like the ones in the asteroid belt today, study co-author Bernard Wood, a geochemist at the University of Oxford, said in an interview. It's a theory that fits quite well with what's been studied on Earth, though it's not a perfect fit, he said.
"That sort of roughly works, but there are all kinds of little questions that don't quite work," Wood said, "and one of them is, what is the energy source that drives the Earth's magnetic field?"
Here's the problem. To drive Earth's magnetic field, you need radioactive elements like potassium, thorium or uranium - elements that give off heat as they decay - to also be in the planet's churning iron core. Those elements love getting together with oxygen, making oxides - but oxides are really light and would float toward the planet's surface; they wouldn't be heavy enough to stay in the core. These elements also hate getting together with iron.
more ...
2 replies
= new reply since forum marked as read
= new reply since forum marked as read
I have lost track of where this was but some years ago J Marvin Herndon had theory of a Nuclear Fission Georeactor at Earth's Center which would be responsible for continuing to generate the heat necessary to keep the core liquid enough for the earth's magnetic field to be generated. It would also potentially explain why the earth's magnetic field waxes and wanes over the years as it would take time for fission poisoning waste products to diffuse away so reaction rates can increase.
I believe a major objection to the theory was the heavy radioactive elements would not be able to reach the core because they would react with oxygen and float.
Cool either way.
