2
votes
3answers
2k views

Is the Earth negatively or positively charged?

The Earth carries a negative electric charge of roughly 500 thousand Coulombs. Does that mean the Earth is negatively charged?
4
votes
2answers
241 views

Why do clouds appear black?

I have noticed clouds appearing black during rain. But I don't know what makes clouds to acquire that colour. This phenomenon doesn't appear every rainfall. There has to be distinction to white ...
12
votes
2answers
5k views

What is the net charge of the Earth?

This question arose in a seminar today about the solar wind... This is my vagueish understanding of the problem - please correct if you see errors! The 'classical' picture of atmospheric electricity ...