hold your terror close

i wanted to illustrate a piece that combines my interests in magnetism and polar exploration in some type of way!

magnetic reversal -> a magnetic reversal, where earth's north and south magnetic poles flip, is a very common occurrence in earth's geologic history! our magnetic field is often modeled as a bar magnet, but it is actually caused by convection in the liquid outer core. the four panels on the right show a modeled process of what our magnetic field looks like when it undergoes a field reversal (our last reversal was ~780,000 years ago!) the top panel shows normal polarity (we're in this rn!), where the field lines (imagine arrows) leave the geographic south pole (Antarctica) and enter the earth at the geographic north pole (Arctic). (this can be confusing because our magnetic north pole is actually our geographic south pole but i wont get into that....)

on geologic timescale diagrams, the barcode black and white bars indicate reversals, where black is normal polarity and white is reverse polarity. in my drawing, to the right of the panels, show my version of this, with dark blue (normal) and cyan (reverse).

the two middle panels show what a full field reversal is modeled to look like as it transitions between normal polarity (top panel) and reverse polarity (bottom panel). reversals can happen pretty fast (centuries to thousands of years to occur!), but they definitely do not switch over night. reversals often start with a weaking of the field at the poles, in which case sometimes, the poles start to migrate and may even flip if it results in a more stable configuration! short-term reversals are called excursions (flipped but didn't like it!! flipped back!)

it's true... our magnetic field is decreasing and has been for some time.... but on geologic timescales it means nothing!!!! ppl like to claim that we're due for a magnetic reversal (ANY TIME NOW THEY SAY) but have no proof!!! don't get me started!!!! so many studies have been done and show that it is CURRENTLY impossible for us to predict the next full field reversal through our past field data!!!! see my comic for more passion on this!!!!!!!

(a lot of this is just sourced off the top of my head cus it's my research so disclaimer,,, if someone is really passionate about wanting sources/studies for this, reach out to meeeee)

arctic tern -> this bird makes the longest yearly migration of any animal, traveling between its breeding grounds in the Arctic all the way down to Antarctica for the summer! that's ~50,000 miles round-trip each year (source) but how do they know their way, you might ask???? yes, you guessed it!! they follow the magnetic field!! yippee!! it's called magnetoreception, and either by the magnetite-based receptors in their beak or a possible protein in the eyes (idk im not a biologist), birds (and turtles) have the ability to sense the magnetic field, and use it to migrate back and forth!

so, i have not been able to find any research trying to prove this in the fossil record (though my paleo-magnetism/ntology office has long debated how to make this a project), but it is hypothesized that magnetic reversals would/will have effects on migratory birds and turtles. hence why i chose these themes!!

poor birds getting lost :(

background -> an aurora! these phenomena are created when charged particles carried by the solar wind interact with gases in Earth's atmosphere. these are found around the northern (aurora borealis) and southern (aurora australis) poles as particles become trapped in our magnetic field and are funneled down into our atmosphere. the wavy patterns are caused by the force of the magnetic field lines. during geomagnetic storms, there is an increase in these solar particles which allow people to see the auroras in lower latitudes than normal! (source)