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Spiders Fly Using Electricity

07/06/2018 1:52 PM

The earth and ionosphere is a giant capacitor, charged up by thunderstorms all over the world. The normal atmospheric electric field is about 100 volts per meter, but it may be many times this value near thunderstorms. Apparently, spiders can use this field to levitate and travel long distances.

https://www.theatlantic.com/science/archive/2018/07/the-electric-flight-of-spiders/564437/

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#1

Re: Spiders Fly Using Electricity

07/06/2018 3:37 PM

Could I see a scaled-up version for human travel...?

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#2
In reply to #1

Re: Spiders Fly Using Electricity

07/06/2018 4:12 PM

That would be nice. The normal terrestrial field is 100 v/m = 100 nt/coul, about 22 lb lift per coulomb of charge, but 1 coulomb is one heckuva lot of charge. You would need a pretty good insulator to keep 1 coulomb of electrons together in a reasonable size volume.

Charge is a surface thing and weight a volume thing, so the square to cube ratio is much better for tiny spiders. And I think they take off when there is a nearby thunderstorm and the electric field is 100 times normal. I don't think you want to fly in a thunderstorm with coulombs of electrons onboard to attract lightning bolts!

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#3

Re: Spiders Fly Using Electricity

07/06/2018 5:00 PM

If seen from a distance, would they be considered UFO's?

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#4
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Re: Spiders Fly Using Electricity

07/06/2018 7:31 PM

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#7
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Re: Spiders Fly Using Electricity

07/07/2018 12:35 PM

Only if you can't identify them.

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#5

Re: Spiders Fly Using Electricity

07/07/2018 12:12 AM

Would you have a video showing spiders riding a lighting bolts tail ?

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#6
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Re: Spiders Fly Using Electricity

07/07/2018 11:18 AM

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#8

Re: Spiders Fly Using Electricity

07/07/2018 12:48 PM

I have often wondered if it is possible to use the Earth's magnetic field to elevate an object. It is weak, but if you had a strong magnet could you levitate the magnet? The force between two magnets is proportional to the product of the intensity of the two magnetic dipoles, so it would seem that if you had a very strong magnet and point its South pole downward at the Earth's magnetic South pole (which is actually near the Earth's geological North pole), then they would repel each other.

I'll bet someone here knows the math well enough to say how feasible this would be.

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#9
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Re: Spiders Fly Using Electricity

07/07/2018 3:55 PM

The only repulsion force would be from a region of higher magnetic intensity to a region of lower intensity. This change in intensity or field gradient is even weaker than the earth's magnetic field itself.

Magnetic repulsion is rather tricky. Certain substances are diamagnetic and repelled weakly by a magnetic field. Pyrolytic graphite is both very light and diamagnetic and can be made to float above very strong neodymium iron boron magnets when they are arranged so that there is a strong magnetic field gradient.

An extremely strong electromagnet can levitate other objects. Again, it requires a strong gradient in the field. Here is shown a frog being levitated magnetically.

A magnet can repel another magnet with the proper orientation. Usually, this orientation is unstable and the repelled magnet will rotate to an orientation where it is attracted instead. An exception to this is a spin stabilized magnet called a Levitron. Again it works only above a special magnet where the magnetic field changes in intensity, and the top is stable only within a very small volume.

Again, to get any lifting force, you have to be in a region where the magnetic field changes from strong to weak in a short distance. The earth's field is so large that this gradient or change in strength is very small everywhere.

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#10
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Re: Spiders Fly Using Electricity

07/10/2018 2:50 PM

Thanks. Very comprehensive.

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