Planets at different static potentials? - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: July 07, 2017, 12:16:44 am
content: If we take the sun as a zero reference (I hesitate to use the term ground) then could the earth be at several million volts above or below this reference? And more to the point, if we launch a spacecraft to say Mars, what is the possibility of it being a bazillion volts different to earth? As the spacecraft approached Mars, seeing there is no atmosphere, once the craft got close enough there would be the mother of all static discharges. Or does the solar wind take care of all of this and keep the planets discharged wrt the sun?

author: xrunner
author_rank: Super Contributor
timestamp: July 07, 2017, 12:42:04 am
content: Well I'll probably make a fool of myself but I don't think a planet in toto would have a large charge because all atoms want to normally have a neutral charge (same # of electrons as protons). Yes atoms can lose electrons but the aggregate chargeover the planetI think would be pretty balanced.But I really do not specialize in planetary charge analysis.

author: rs20
author_rank: Super Contributor
timestamp: July 07, 2017, 01:24:30 am
content: At a different forum (link), Vanadium 50 states:Quote from: Vanadium50Sounds pretty legit to me. Also, wikipedia states that theinterplanetary mediumis a plasma and as such is "highly electrically conductive". Of course, it's not quite that simple because (perfectly) conductive things ought to be reflective, not transparent, but I think it does hold true that if your craft has any significant charge on it, it'll just attract opposite ions and neutralize itself.

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 07, 2017, 01:38:20 am
content: Don't we already have 50 years of practical experience with Earth-origin craft landing on the moon and other planets? Surely we would have detected some significant static discharge. But since craft are AC-coupled, difficult to see how you could get any kind of realistic differential measurement over planetary distances.

author: Electro Detective
author_rank: Super Contributor
timestamp: July 07, 2017, 01:53:01 am
content: Science teacher said there is galvanic isolation in space between destinationsany unlikely zap potentials die off, or can't travel in a vacuum anywaySpace ship frame teminates all zaps upon landing on ground, moist ground preferredScience teacher made good use of his whiskey flask during class, so...

author: mtdoc
author_rank: Super Contributor
timestamp: July 07, 2017, 05:20:06 am
content: Quote from: Richard Crowley on July 07, 2017, 01:38:20 amYeah, it would require some hella long Meter leads....

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 07, 2017, 06:19:34 am
content: Quote from: Richard Crowley on July 07, 2017, 01:38:20 amAh, not necessarily! The craft are influenced by electrostatic induction as they approach another object, so that the charge difference is somewhat less than you would measure at a great distance (assuming such a measurement could be made...Quote from: mtdoc on July 07, 2017, 05:20:06 am^^)AFAIK, the maximum potential for any object, versus solar wind (minding that the wind itself isn't perfectly equipotential; I'd expect it has seriously strong 1/f noise, given the turbulent source; but, I don't know of any reference stating this for sure -- would be interesting to research..?), is on the order of millions of volts. This corresponds to the peak energy level of the wind itself. If you had a greater potential, particles in the wind (positive or negative) would be captured by the potential well, rather than zooming on past; if you had less potential, some particles (say water molecules, and their components (hydroxyls and protons), in the upper atmosphere) will be knocked loose, given the energy to reach that potential.And, electrons being lighter than protons or other ions (positive or negative), objects should tend to get a positive charge (shortage of electrons). Although I don't know if I've ever seen a measurement of this..?Tim

author: TerraHertz
author_rank: Super Contributor
timestamp: July 07, 2017, 08:30:52 am
content: You just bit into a HUGE topic. A few points:* The universe by volume is about 9.99999999% plasma. Doesn't matter that it is mostly very high vacuum plasma, it's still plasma.* The physics of plasma behavior is incredibly complicated, and very counter-intuitive. Plenty is still not understood.* For instance, in plasma electrostatic charges often do NOT equalize out. Really huge voltage differences can build up. There are all kinds of effects like double-wall layers, Birkeland strands, pinch effect, etc, that simply don't happen in our planetary surface experience.* Astronomers tend not to be taught plasma physics, so a great deal of astrophysics is hand waving bullshit. Including a lot of theory on what goes on in stars. In which plasma and electrostatic effects play major roles. Stuff like "magnetic field lines breaking and reconnecting" - this is utter stupid ignorant crap, yet you will hear it from astrophysicists often.Anyway... yes, planets and stars can and do build up huge potential differences between themselves and surrounding interstellar plasma medium. And there are macro effects. Plenty of argument about whether Earth has been subjected to such effects in human history (or not.) You can find some really interesting stories...Also more recent tales. The NASA 'tether experiment', the comet impactor, upper atmosphere 'sprites', whether comets are icy, or highly charged rocks with lots of glow discharge, sputtering, electrostatic HV chemistry and erosion... etc.There's a whole camp of theorists going by the name Electric Universe. Plenty of links, many hours of reading in my list:http://everist.org/archives/links/__Electric_Universe_links.txt

author: PauloConstantino
author_rank: Regular Contributor
timestamp: July 07, 2017, 08:39:59 am
content: I think the planets aren't at different potentials since they came from the same potential originally (the rocks and dust and stuff swirling together originally).

author: TerraHertz
author_rank: Super Contributor
timestamp: July 07, 2017, 09:22:04 am
content: Quote from: PauloConstantino on July 07, 2017, 08:39:59 amYou should find reading up on Electric Universe quite exciting then. There's nothing like the thrill of finding out something you believed is completely wrong.

author: tszaboo
author_rank: Super Contributor
timestamp: July 07, 2017, 09:30:50 am
content: As I understand, Earth has a small self-capacitance. According to Wikipedia, its only 710uF. So even if the difference is 1000V, its only 355 Joules of energy, if you discharge it.And I guess, a spacecraft will gradually discharge in the atmosphere. I guess.

author: Brumby
author_rank: Unknown
timestamp: July 07, 2017, 09:48:21 am
content: Quote from: Electro Detective on July 07, 2017, 01:53:01 amFrom my experience, don't expect a science teacher to extend their knowledge past the syllabus with any measure of competence..In high school I answered a question about an example of resonance with something unusual. It was marked wrong. Over the years I have revisited my answer several times and it was the teacher (the science master, actually) who was wrong.The silly things that burn a mark in your memory. ..