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On 4 Jan 2001, mehmet wrote:
> HI,
> I have a question concerning Universe and charges. I would be glad if you can
> explain to me, is the Universe is charge neutral, that is it contains an equal
> number of protons and neutrons?
Hello,
First, just a brief clarification. Protons carry positive charge, but
neutrons are neutral, carrying no charge. So if we want the universe to
have no net charge, then the universe must have equal numbers of protons
and _electrons_, which are negatively charged particles.
But, anyway, the universe does appear to be neutral overall. Most
theories of the creation of the universe imply that there are equal
numbers of protons and electrons. But that begs the question, is this
really true?
The answer appears to be that, as near as we can determine, the universe
is electrically neutral. The electromagnetic force is so strong that if
the universe had even a slight net charge, electric and magnetic fields
should dominate the structure of our universe. But it doesn't -- gravity
does. And gravity, believe it or not, is a very weak force. Notice that
a small magnet can pick up a paper clip, even though the entire Earth is
pulling downward on the same paper clip!
There are other effects that electric and magnetic fields would have on
light, and we simply do not see these effects. So, while we cannot be
certain that there is no net charge in the universe, the universe is so
nearly exactly neutral that we cannot tell the difference.
Thanks for writing!
Sincerely,
Kurtis Williams
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