Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Losing electrons

  1. Dec 11, 2009 #1
    The following statement I have found in a book:

    Between an apple and the Earth, gravity dominates because both the apple and earth are electrically neutral, to a high precision. Matter is neutral to a better part than 1 in 10^20 in order for the electric force of repulsion between the apple and earth to be similar to the gravitational force between them, only 1 atom in 10^20 would have to lose an electron.

    So to make an apply about the earth float, we need them to lose an electron each?

    Does this make sense? How much energy does it take to lose an electron, and can
    this be accomplished?
  2. jcsd
  3. Dec 11, 2009 #2
    As I read the quote, it doesn't have the implication you think.

    If, for every 10^20 atoms in earth, 1 would need to lose an electron, then to find the number of electrons that would have to be lost by the earth, you need to know the number of atoms in the earth and divide it by 10^20. Similarly for the apple. Since there are rather a large number of atoms in the earth, and in the apple, that does mean losing a large number of electrons. I've seen the number of atoms estimated at around 10^50, so about 10^30 electrons would have to be lost by the earth alone. Fewer by the apple, of course. But still, quite a lot.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook