ronflair t1_jdscqhs wrote on March 26, 2023 at 8:29 PM

Reply to comment by PolymerPolitics in Around 550 million years ago the earth's magnetic field almost collapsed, but then strengthened a few million years later. Scientists say this may have been due to the formation of the inner core. But why exactly would that cause the magnetic field to get stronger? by somethingX

Depends on the depth. According to this site, a water layer 7cm thick reduces ionizing radiation dosage by about half.

https://space.stackexchange.com/questions/1336/what-thickness-depth-of-water-would-be-required-to-provide-radiation-shielding-i

If correct, means that cyanobacterial mats inhabiting the top layers of oceans will still be receiving significantly more ionizing radiation than normal. We’re not talking about enough radiation to sterilize the planet, just enough to significantly increase the rate of mutagenesis.

Octavus t1_jdsj58i wrote on March 26, 2023 at 9:14 PM

You are forgetting that the atmosphere is responsible for the bulk of Earth's radiation shielding and is equal to about 10 meters of water.

ronflair t1_jdskzk1 wrote on March 26, 2023 at 9:28 PM

You still would get a net increase in surface ionizing radiation, which would increase as a positive feedback loop the longer the magnetosphere was “off”.

According to NASA, a prolonged loss of the magnetosphere could erode the protective layers of the atmosphere. More cosmic rays would reach the surface as well.

https://science.nasa.gov/science-news/news-articles/earths-magnetosphere