If a planet had such a large imbalance of protons and electrons that it possessed a net negative or positive charge what would happen to it and its solar system?

First, could it be stable, or would it simply disintegrate? Would the charge act against the pull of gravity and make everything on the surface weigh less?

Second, what effect would the charged planet have on its moons, neighboring planets, or sun? Would it polarize them, and how would it affect their orbits?

Third, what would the chemistry and biology be like on the planet's surface? Could life develop. Would the chemical reactions possible be radically different? Would elements exist in different forms?

Finally, what would happen to something that got too close like an explorer's spacecraft?

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    I would have to research more for a full answer...but I don't think the setup could exist. The Earth itself is decently electrically charged, it's the electrical flow through the molten core that results in our magnetic field. To have the entire planet negative or positively charged...I dunno. The sun is heavily charged as well. Need some more research time...it'd be interesting answering this question with the assumption that this could exist. – Twelfth Oct 9 '14 at 18:09
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    Here is an article discussing the Earth’s net electric charge which mainly arrives at the result that we cannot measure it. While it’s already 25 years old, there is no literature building upon it which seems to have new information. – Wrzlprmft Oct 9 '14 at 19:50
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    There is also this article which is newer but has not been published in a peer-reviewed journal. It estimates the charge of the whole planet (with athmosphere) to be −1 C. – Wrzlprmft Oct 9 '14 at 20:04
up vote 6 down vote accepted

I don't mean to disappoint you but planets are already charged - all bodies in space have a voltage that depends on their immediate environment to the degree that they interact with it through the interplanetary medium, which transfers charge to an extent.

Being isolated most of the time, they develop a potential compared to other objects due to the balances within their immediate environment being satisfied but by not having contact with other objects, their relative potential doesn't balance because their charges don't interact.

This is why in electronics and electrical engineering, two points cannot be compared in terms of their voltage, unless they share a point, usually ground. An example would be two batteries - while the voltage between their ends can be approximately the same (lets say 5V), if they're isolated from each other completely and you place a wire near them with a high enough voltage to overcome air resistance (say, 50 kV), against one there might be a spark, but not against the other, at the same distance (provided you kept the wire at a constant voltage). While this is unlikely to happen in the same room, due to the air balancing out charges through interaction and friction, it is possible to observe this difference experimentally. The ground in England is not the same ground as in Italy - but the voltage between the ends of batteries will be.

In much the same way, if two celestial objects where to pass close enough to each other to interact electrically, there would be huge lightning bolts. You don't see this often with asteroids because they don't often pass close enough to other objects and because given enough time in the same environment, their effective potential balances out.

But to answer the question, a planet can and does have a net charge - it's not something exotic, it would be exotic if it didn't.

  1. Celestial objects are too far from each other to interact electrically this way, although they do interact through the interplanetary medium, albeit at a much smaller degree

  2. Electricity and gravity don't interact the same way with matter. If a planet had a net charge, everything on it would share that net charge. Unless we're talking about a huge volcano (where events are violent enough to cause lightning), a thunderstorm, a tornado or an earthquake (where separations are again violent and there's a lot of friction involved), you wouldn't see much of a difference. Also magnetism is not electricity - they're related but not the same effect - unless the magnetic poles shifted dramatically (which does happen but never abruptly), you wouldn't notice much changing.

  3. It would have as much an effect as it has now, on other bodies - the Sun controls most of what happens with charge within the solar system as it has the most powerful charge flows and emissions. It's hard to imagine a planet having a stronger effect on the charge of its surroundings than the star they orbit. Even if it were to happen, only the planet would face the consequences, not even moons.

  4. Life would be no different - in fact, lightning is considered to be part of the necessary ingredients to get life and in the primordial Earth, we probably got tons of it all the time. With time, life adapts, the atmosphere stabilizes and things work out fine. The elements would also be the same, chemistry would be the same.

  5. If the spacecraft entered the planet's environment too fast, it could get struck by lightning when it enters the higher (near space) layers of the atmosphere. But that would be easy to mitigate by just slowly adjusting its orbit until the potential is equalized, provided the pilot was prepared for this case.

Also, check Richard Tingle and supercat's comment's down below for more perspective.

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    Re not seeing any difference because everything has the same charge: in the van de graph hair sticking up experiment all your hairs have the same charge and as a result repel each other. In a ridiculously highly charged situation (and I mean ridiculously) you would expect to see some effects (up to and including a breakup of the planet) – Richard Tingle Oct 9 '14 at 18:40
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    I'm not sure what would cause lightening in this scenario (except when things entered the atmosphere of cause). Electrical effects are all about potential differences and I can't see any reason why the potential differences would be any different from the real earth. On the other hand repulsive effects are all about actual charge which would be huge – Richard Tingle Oct 9 '14 at 19:03
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    I've got out newtons law and colombs law and calculated the charge it would take to overcome gravity and I've come up with a very suprising result. Every kg of matter would require only 0.09 nano colombs of charge per kg (9*10^-11 C/kg) to completely overcome gravity. Of course that wouldn't breakup the rocks etc but all air, water, soil and other loose material would be lost at that point. For context static charges by rubbing are generally in the micro colomb range – Richard Tingle Oct 9 '14 at 20:05
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    Indeed, in fact the evaporating atmosphere would make it even harder to maintain the isolation (and the energy requirements to charge the planet would be hilarious). The maths works out that way because gravity is stageringly weak compared to other forces (the fact that a charged hair or small magnet can hold something up against a whole planet's gravity highlights this – Richard Tingle Oct 9 '14 at 20:35
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    A lot of particles, some of which are charged, enter and leave the Earth continuously. If the Earth had a significant positive net charge, that would increase the rate at which negatively-charged particles are captured by the Earth's gravitational field, as well as the rate at which positively-charged ones leave. – supercat Oct 9 '14 at 22:20

The earth already has a minor negative charge. This is what causes lightening. However, overall the planet is very close to neutral when combined with the atmosphere.

I do not believe that an electrically charged planet would be stable. The elcrical force is orders of magnitude stronger than the gravity. If the planet was charged, I believe the planet would immediately stabalize. There are so many free elctrons and other particles coming from the sun, that the planet could use to revert to neutral.

Even if a planet didn't quickly revert to a neutral charge, how could you create an electric charge on a planet? The electric force is effectively conserved. (Technically you can could chuck unwanted electric charge into a black hole and get an imbalance that way but that's a whole other can of worms.) Electrons and protons come in a pair and the electric force is very strong. What force would strip the protons and electrons apart, leaving one on the planet and driving the other far enough away that it didn't merge back into the planet. Given this, I don't know of any way to generate a large enough charge on a planet to be interesting.

Sure, a planet could have “a few” too many or too few electrons to be exactly neutral, but such would be on the same order of magnitude as the separation of charges within different parts of the planet.

If you're thinking of a charged planet throwing lightning bolts to other worlds, or having electromagnetism play a noticeable role in its orbit (like in some of the later works of James P. Hogan), that would not happen. A strong charge would neutralize itself far faster than geologic time scales.

Consider an airless body like our moon. It is bombarded by particles from the solar wind, and UV radiation can knock out electrons. Why doesn't the moon build up a charge that keeps growing for billions of years? At some point incoming charged particles won't stick but bounce away, and charged particles are shed.

In a body like the Earth, the geomagnetic field shields against most of the solar wind, but if the Earth somehow had a large charge, it would preferentially lose charged particles in the air that slowly leaks away to space; or would strongly repel charged gas molecules and outgas quite rapidly.

  • I would expect that many bits of stuff in space have small positive or negative charges. If a planet had a really large positive charge, that would reduce the number of positively-charged bits of space junk hitting it, while increasing the number of negative ones, to the point that the net charge on the planet was comparable to the average charge on the bits of space junk hitting it. – supercat Oct 20 '14 at 16:45

Other answers are correct in saying that (a) celestial bodies generally do have a non-zero charge and (b) if a planet were very strongly charged then it would quickly suck opposite-charged particles from the solar wind until it was approximately neutralised.

But suppose an Earth-like planet did magically have a strong permanent negative charge. You have a surplus of electrons, which repel each other, so broadly they will try to spread out as thinly as possible. If the charge is completely evenly distributed, then things aren't so different to Earth, except that the ground voltage is much lower than on Earth, though you wouldn't know it unless you ran a cable between the two planets.

The excess electrons mean that the formation of negative ions is easier, and the formation of positive ions is harder. So I guess, crudely speaking, the planet will be a little more alkaline. The relative rates of various chemical reactions will be slightly different, but all the same chemistry will exist.

Weather would be different. Because different gases can hold different amounts of charge per unit mass, I believe the movement of wind would cause the excess charge to become unevenly distributed, resulting in lightning. Also, the atmosphere would eject more gas into space – the negatively charged planet will repel negatively-charged gas ions. (This is also one of the ways the planet would shed its excess electrons IRL, but we are stipulating that the electrons get replaced somehow). Because of this, the atmosphere would be thinner.

While the other answers covered this realistically I think you can take another spin on it. For a large net charge I believe you'd have some interesting effects. (the following is based off logical reasoning on the bold item scaled up to planetary sizes).

Thinking of the atom: It would be stable up to a very large charge just due to the weight. At larger charges the the center might become less dense but the surface gravity would not be effected.

Thinking of an electric generator: If objects were oppositely charged they'd probably generate magnetism in the negative object, huge electrical storms, and possibly arcs if close enough. They would at the very least generate an ion stream. It would change the distances and speeds of the orbits but would not effect the shape.

Thinking of Ionizing Radiation: Life doesn't like ions and you have a lot of them flying around, especially if the flow is from the planet instead of from the sun. So you'd probably have none of it. As the percentage of charged particles increased the chance of forming compounds would go down as nothing would be forming ionic bonds and two ions don't really like to form covalent ones. I don't know about planetary-sized objects, but at least for star-sized ones you'd have some very different materials than normal in the core, as they would bond despite charge.

Thinking Dust Wiper: We have materials such as microfiber which exhibit electrostatic adhesion (there's a name for this type of material if someone can find it), and your charged objects would behave just like them, pulling in oppositely charged objects and probably trying to ionize the other object and end up pulling it in anyway (like amber does when it exchange charge). So expect any passing ships to stick to your planet like tape.

Well, if you live in Europe, you might see three holes in the plug in the wall. The bottom one is GND (Ground). It is connected to earth. It is meant to be so, so if a lightning strikes the building, it will not pass the charge to US but to EARTH. The earth's core is filled with liquid metal, and this generates some electric charge, mostly negative one - it has more protons that electrons. The earth itself is generating electricity, and some of it comes from our activity as humans, and lightnings.

Best of Regards, Itay Tip: In a lightning storm - never play golf :)

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    You cannot generate negative electric charge without also generating positive electric charge, as electric charge is a conserved quantity. Thus the only way to negatively charge the earth is to send positive charges into space or to receive negative charges from space (which actually happens). – Wrzlprmft Oct 9 '14 at 17:58
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    The science here could use some work. – bowlturner Oct 9 '14 at 18:00
  • Stack Exchange questions and answers do not start or end with a greeting. The context is clear so a question or answer can stand alone. – trichoplax Oct 9 '14 at 19:39
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    The earth wire is to protect against insulation failure in the device, not against lightning strikes. – trichoplax Oct 9 '14 at 19:42
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    I'm aware this is a lot of feedback at once. It isn't intended to be negative. Once you hit 20 reputation (2 upvotes on an answer or 4 upvotes on a question) you can join us in the site chat and ask about anything else you want to know. In the meantime, keep asking and answering questions and welcome to worldbuilding... – trichoplax Oct 9 '14 at 19:55

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