The Anti-Magnetic Mass Extinction

An exploration of the strange mineral bridgmanite, and how it could eventually shut down earth's magnetosphere in the far future and cause the greatest mass extinction earth has ever known.

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Links:

"Radiative thermal conductivity of single-crystal bridgmanite at the core-mantle boundary with implications for thermal evolution of the Earth", Murakami et al., 2022

"Six ‘Must-Have’ Minerals for Life’s Emergence: Olivine, Pyrrhotite, Bridgmanite, Serpentine, Fougerite and Mackinawite", Russel and Ponce, 2020

Music:

Intermission in D by Miguel Johnson

[panchogeorocks]

As a geologist, this scenario would make sense, but one key fundamental thing has been left out. Subduction zones bring water into the asthenosphere/upper mantle. This lowers the melting temperature of the surrounding rock and thus, trigger partial melting of the upper mantle . It would take quite a bit to slow subduction zones to completely cease partial melting and therefore, the upper crust and asthenosphere becoming more solid and stop plate tectonics. I think the sun would burn us to a crisp before it reaches the red giant phase in its stellar evolution before plate tectonics completely stop. While earth is losing heat, it's not at the rate where within a billion years, it's going to slow down plate tectonics significantly enough where the geodynamo will be effected and its ability to generate a strong magnetic field to protect earth from the sun's stellar wind.

[cheradenine]

_BREAKING…_
NASA considering using JMG videos as novel propulsion method to reach nearby star systems.

[Mudinjector]

Hey John Thanks for being such a legendary creator

[ucantSQ]

Super cool. I can't wait. You'll see me in the parking lot afterwards. I'll have the tee shirts that read:
3 billion years of tortured evolution and all I got was this lousy core death.

[GizzyDillespee]

"Only the sun can destroy all life on Earth"

World leaders: Sounds like a challenge, to me!

[raymondcoventry]

No one outputs quality and quantity like JMG

[joshr]

Got me drifting into a restful slumber to descriptions of apocalyptic horrors

[Yezpahr]

I think Theia has a huge role in why we still have a viable planet.
It mixed everything, trapped an enormous amount of extra heat down there, some bits and pieces are still boiling off (which actually might be the kickstarter for convection in the first place) and that all might have kept volcanism around for longer.
Still just a theory that many subscribe to, but there's no reason it would have hampered development of life instead of aiding it. Life certainly doesn't predate it.

[CHO]

We dont understand earths magnetism anywhere near as much as we should...

[lnchgj]

5:50 The earth’s core’s sources for heat. You missed one. Tidal forces. Just like the oceans, the ‘dirt’ rises and falls as well. (Do remember that both the moon and sun contribute in this) While at least, this gradational kneading of the earth, by heating it, reduces the cooling of the core, it’s just as likely that it contributes to the hating of at least the outer core. A question. If the earth losing its magnetic field will mean it will lose its atmosphere, then how does Venus, much closer to the sun and without a magnetic field, still have an atmosphere 90 times what the earth has.

[quahodron]

Dear John, I just wanted to state, that I really love your videos. I'm watching your videos for quite some years now and I really appreciate them. 🖖

[heavencanceller]

I love your videos! They've been helping me wind down for the night for a long time

[erichtomanek]

We should work on the assumption that we only have 500 million years left.
So, chop, chop!
Let's get to it and colonize the galaxy!
Time's a wasting!

[vicsmusicalgarden]

It is the cooling of the outer core (heat transfer to the mantle) that drives the convection of the molten iron that gives rise to Earth’s magnetic field. The more rapid the cooling, the stronger the convection, the more stable the magnetic field.

[thomaslamb]

Well, what a ray of sunshine this topic was.

[vicsmusicalgarden]

Of course it’s fun to think about this stuff for SciFi.

By the way, I’m a retired paleomagnetist.

[ViolencevAction]

Happy Shiny People holding hands… just felt that line was needed after getting blindsided by the fact planetary geology could be ending life on earth prematurely….

[DrSausagee]

Once again, extremely thought provoking and fascinating. Thank you so much for this content john.

[daveycrockett]

0:19 Excellent insight as per usual Mr. Godier. You've have some interesting topics lately which have been very pleasant to listen to.

[Preston]

Currently worrying about an event the will occur at least a billion years after my death.