Page 43 - The Miracle in the Atom

A set of three
quarks – these
make up a
proton – would
have strings at
their heart.

wing result: if we assume the atom to be a sphere, if we wished to fill this
sphere totally with nuclei, then we would need 10 (1,000,000,000,000,000)
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nuclei to fill it. 16
Yet there is one thing even more surprising than that: although its size
is one ten billionth of an atom's size, the nucleus' mass comprises 99.95% of
the mass of the atom. How is it that something constitutes almost all of a gi-
ven mass, while, on the other hand, occupying almost no space?
The reason is that the density comprising the mass of the atom is not
distributed evenly throughout the whole atom. That is, almost the entire
mass of the atom is accumulated in the nucleus. Say, you have a house of 10
billion square metres and you have to put all the furniture in the house in a
room of one square metre. Can you do this? Of course you cannot. Yet, the
atomic nucleus is able to do this thanks to a tremendous force unlike any ot-
her force in the universe. This force is the "strong nuclear force", one of the
four fundamental forces in the universe we mentioned in the previous chap-
ter.
We had noted that this force, the most powerful of the forces in nature,
keeps the nucleus of an atom intact and keeps it from fragmenting. All the
protons in the nucleus have positive charges and they repel each other beca-
use of the electro-magnetic force. However, due to the strong nuclear force,

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