why does some lightning seeks the ground while others go across the sky? What happens to the plasma?
In: Earth Science
okay so, during a thunder storm, the ground and the sky have much different charges. The ground is far more negatively charged than the sky is, which by comparison is very positive. But way high up in the cloud, the cloud is still the same as the ground, and compared to the bottom of the massive thunder cloud is also very negative.
there are these things colloquially called “freys”, which are streams of electrons being given off. This is normal, an exchange of electrons happens all the time everywhere. but since the difference is SO huge, and nature seeks equilibrium, the effect can be very strong. You might see pictures of people’s hair standing up, or a very well-known but not well understood phenomenon called “St. Elmo’s Fire”. What you’re seeing in these instances is that the electrons are so incredible powerful in number that they’re changing the polarity of things all around you, your hand, your hair, the air- static electricity, as in, electricity that cannot go anywhere yet. For you it’s pretty weak, but say… for a large metal pole? it’s going to be very strong, because it conducts electricity- the movement of electrons- far better than your flesh does.
a small example is you shuffling your feet on carpet. You’re sending out freys, because of that difference, and then you get close to your friend and you’ll zap them before you even touch them because your freys have touched their physical body and completed a ground circuit. That little zap is the instantaneous “equalization” of electrons. that’s lightning but tiny. now that you’re equal, you can’t really zap them again until you shuffle some more.
So those freys go up in the air, but also, they’re being sent down by the cloud too. Anywhere there’s inequality you’ll get those freys. When the freys connect, you get that equalization of electrons…. and that’s a big fucking lightning bolt that flashes and superheats the air creating a loud bang that frightens the hell out of your dog. **that is how lightning happens**. For now, the cloud and the ground is equal, but since the cloud is still moving, it won’t be long until it builds up a charge again. Or maybe that single bolt didn’t equalize it enough, and there’ll be another one soon.
as for the lightning within clouds, that just means the differential in electric charge inside that cloud is big, as well. It’ll seek to equalize there, too, and it’s much easier than having to zap the ground.
plasma is just a superheated gas. There might be plasma, I dunno if I’d directly call lightning bolts plasma, it might make plasma… but it isn’t plasma itself.
Electricity wants to travel across the quickest path. Sometimes that path is through clouds (cloud to cloud), sometimes from cloud to ground, etc. That path is dependent on the charge (positive and negative). So if the quickest path between a positive and negative charge is closer in the clouds versus the ground, the path will be across the clouds.
The air quickly cools as it contracts after lightning is generated.
Don’t know about the first part of your question. I can say that I’m pretty certain lightning doesn’t go across the sky, it always goes either from sky to ground or ground to sky, but I’m not 100% on that.
As for what happens to the plasma, once the electricity has stopped flowing through it, it loses its heat quickly, and just turns back into normal air.
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