Discovery of worm neuron that senses Earth's magnetic field


#1

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#3

The press release gives a prominent place to the thoroughly-discredited dog-pooping magnetoreception study. This is not encouraging.


#4

The classic (and very odd) SF novel/future history Last and First Men includes a section in which a future race of humans deals with invading Martians. These aren’t little green men; they are clouds of microbes which use radio to communicate with each other, forming a group mind.

Eventually humanity survives, but they occasionally suffer from lung infections . . . of Martian bugs. Over time they incorporate the creatures into their bodies, effectively becoming radio-telepathic.

Now I’m wondering if we could infect someone with worm neurons and pick up a magnetic field sense.


#5

There are bacteria that have magnetite vacuoules. Specifically soil bacteria and waterborne motile bacteria. It helps them also know towrd the center/toward the sky directionality. Plus i’m pretty sure bacteria-driven computers are in the works so…the list of totally sci-fi ways we wil lead to our own destruction grows by the day.


#6

Side-effects, though.


#7

Kurt Vonnegut had people getting sick from inhaling micro-miniaturized Chinese people, which was not racist in the '70s.


#8

How do these worms find up at the equator, where the magnetic inclination is roughly horizontal? And what happens during a magnetic reversal? And wouldn’t gravity be a much simpler and consistent method of determining up from down?


#9

Nope. Gravity is a very weak force, unless you’re as large as a human.


#10

But what does the planet’s magnetic field tell you about up vs. down? You could determine your orientation along some axes in relation to the field but wouldn’t pointing away from the center of the earth feel identical to pointing towards it, unless you were near a pole?


#11

Wait, what? I think you mean that gravity is a weak force, unless you are as large as a planet. Because that is what matters here, not how much we weigh, but how much the Earth weighs. The mass of the earth is ~10^24 kg, the gravitational force of attraction for a worm, (at lets say a gram, or 0.001 kg) would be 99.999999999999999% the force that we feel (at 100kg).

Gravity is considered a weak force because it is small relative to the strong nuclear force at distances of femtometers, but here in the planet sized world, gravity is still a potent force.

So I still think gravity is a better way to tell up from down, and gravity doesn’t have that problem of reversing polarity every couple hundred thousand years like the Earth’s magnetic field does.


#12

We feel gravity because our own weight presses on the soles of our feet, our muscles must fight it to raise our arms, and so on. If we are in water, there is a pressure gradient. A nematode does not have access to this information because it is too light. The world is isotropic at nematode scale.
Large enough animals – jellyfish, starfish, vertebrates – can evolve statocytes or otoliths where a denser particle indicates the direction of gravity by weighing down against nerve cells. Nematodes are too small for that option.


#13

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