Did you know migratory birds and sea turtles are able to navigate using the Earth's magnetic field? It's called magnetoreception. Basically, being able to navigate was evolutionarily advantageous, so life evolved ways to feel the Earth's magnetic field. A LOT of ways. Like a shocking amount of ways. Here's a few examples:
It would seem evolution adores detecting magnetic fields. And it makes sense! A literal "sense of direction" is quite useful in staying alive - nearly all life benefits from it, including us.
We don't totally understand how our magnetoreception works yet, but we know that it does. In 2019, some Caltech researchers put some people in a room shielded from the Earth's magnetic field, with a big magnetic field generator in it. They hooked them up to an EEG, and watched what happened in their brains as they manipulated the magnetic field. The result: some of those people showed a response to the magnetic fields on the EEG!
That gets my noggin joggin. Our brain responds to magnetic field changes, but we aren't aware of it? What if it affects our mood? Would you believe me if I told you lunar gravity influences the Earth's magnetosphere? Perhaps I was too dismissive of astrology.
But seriously
Biomagnetism is "the phenomenon of magnetic fields produced by living organisms". Hold up. Produced by? I made another list for you:
Weakly electric fish – electric organs generate pulsed currents whose surrounding magnetic fields (nanotesla scale) have been recorded directly near the fish.
Earthworms – single action potentials in the giant axon system produce biomagnetic fields detectable with magnetic resonance spectroscopy.
Crayfish – the giant axon’s action currents generate ~10⁻¹⁰–10⁻⁹ T fields measured directly with toroidal pickup coils.
Frogs – action potentials in the sciatic nerve produce pico– to 10⁻¹⁰ T magnetic fields, recorded non-invasively with SQUIDs and optical magnetometers.
... continue reading