Robert Seeberger wrote:
Robert J. Chassell wrote:
Now I'm wondering if there are sparks when a ship docks at the
space station ...
Interesting. First, I don't think there would be
actual sparks. Electrical sparks happen when the
potential gradient between two charged objects is
too steep and the air there is ionized. The
ionized air conducts current readily, and the
potential between the objects is quickly equalized.
Without air, I think that electrons would quietly
flow to the more positive object, until the potentials
were equal.
Won't both the space station and the ship discharge or attact
electrons though needles, as is done with aircraft?
I think the purpose of the needle is to produce a
steeper potential gradient at the tip of the needle.
This would help ionize the air, but I'm not sure it's
useful in a vacuum.
But what would it bleed off to? If the enviroment is FAIAP a vacuum
then there is nothing to discharge too....I would think!?!?!
Isn't some form of matter (even a plasma or some kind of ion path for
potential equalization) required?
Now if an object has a net negative charge, I claim that
the extra electrons would spread over the outside to the
extent they were able. (If the ship is conductive, they
would be pretty able.) But then why should they stay on
the object? The electric force is pretty strong, so once
an electron gets off the surface of the ship, repulsion
of like charges should push it out into space.
This effect would depend on temperature, as was pointed
out for vacuum tube filaments.
I know the ISS orbits through the most tenuous of atmosphere, but is
it enough to provide a potential equalization path?
I'm betting air is an insulator, and equalization happens
more easily in a vacuum.
Their charge is
the ambient. I remember from 8th grade (which was a very long time
ago; I am not positive of the truth) that corona dischages do not
require an atmosphere, except to be seen.
Sounds right. I think if you can see the discharge in
a near-vacuum, it's like an aurora, meaning your ship
has a rather high charge. I'll pass.
The corona occurs when the atmosphere strips (or adds I suppose)
electrons from the surface of the craft. Once outside the atmosphere
the corona is maintained because there is no place for the charge to
go.
Wait a minute, what's keeping the corona there? Gravity is
all I can think of, and that's pretty weak, even for the
Death Star.
---David
I've got a voltmeter, you bring the spaceship...
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