Overlooked No More: Inge Lehmann, Who Discovered the Earth's Inner Core

92 pointsposted 2 months ago
by Hooke
(nytimes.com)

23 Comments

perigrin

a month ago

All of modern geology stands upon her work.

tekla

a month ago

She was hardly overlooked, she won many honours for her work during her time.

> This article is part of Overlooked, a series of obituaries about remarkable people whose deaths, beginning in 1851, went unreported in The Times.

pfdietz

a month ago

> It explained how the Earth generates the magnetic field that protects the planet from cosmic radiation,

Our protection from cosmic radiation is mostly due to Earth's thick atmosphere, not its magnetic field.

andsoitis

a month ago

> Our protection from cosmic radiation is mostly due to Earth's thick atmosphere, not its magnetic field

Primary defense against cosmic radiation: magnetic field

Secondary defense: atmosphere

https://science.nasa.gov/science-research/earth-science/eart...

pfdietz

a month ago

Yeah, that's nonsense. The radiation in low Earth orbit is only a bit less than above the magnetosphere, and most of that difference is from shadowing by the Earth itself. In contrast, there's a massive decrease in radiation from LEO to to sea level.

Radiation at ISS: 144 mSv per year

Radiation on a trip to Mars: ~340 mSv per year

Cosmic radiation at sea level: about 0.4 mSv per year

The atmosphere is doing the heavy lifting in shielding us from cosmic radiation, not the magnetosphere.

magicalhippo

a month ago

> Radiation at ISS: 144 mSv per year

> Radiation on a trip to Mars: ~340 mSv per year

This seems to track with research that during a geomagnetic excursion[1], where the field strength dropped to about 10%, the cosmic radiation seems to have roughly doubled[2].

[1]: https://en.wikipedia.org/wiki/Geomagnetic_excursion

[2]: https://www.eurekalert.org/news-releases/1041098

pfdietz

a month ago

To steelman the argument, perhaps what the magnetosphere is doing is stopping the atmosphere from making too much carbon-14. In shielding the surface from energetic cosmic rays, neutrons are produced, and these transmute N-14 to C-14 by the (n,p) reaction.

andsoitis

a month ago

> Yeah, that's nonsense.

Assuming you're right, why do you suppose so many publications get it wrong?

Not only the NASA one I linked to but also Wikipedia for example: https://en.wikipedia.org/wiki/Cosmic_ray

Or the European Space Agency: https://www.esa.int/Science_Exploration/Space_Science/Cluste...

You will forgive me if I take their assessment more seriously than yours, but I'm open to correcting my understanding.

pfdietz

a month ago

It's in the interest of NASA (and the ESA) to hype the importance of the magnetosphere. After all, they are given money to investigate it, so the more important it is perceived, the more money they can expect to get.

andsoitis

a month ago

> It's in the interest of NASA (and the ESA) to hype the importance of the magnetosphere. After all, they are given money to investigate it

I don’t know that that is a good reason to cause you to you think they’re lying.

NASA also extensively investigates Earth's atmosphere.

They use missions like Aura, CALIPSO, and upcoming ones like AOS and INCUS to monitor ozone, clouds, aerosols, and storms, providing crucial data for forecasts and climate science.

pfdietz

a month ago

They aren't "lying", they're "stretching the truth".

I don't know why you'd expect a self-interested organization to do anything else.

nephihaha

a month ago

The magnetic field deflects particles from the Solar Wind, whereas the atmosphere blocks a lot of the radiation as I understand it.

pfdietz

a month ago

The solar wind != cosmic radiation.

user

a month ago

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