A gap of four orders of magnitude
then ensues between the nearest star and the most distant planet,
similar to the difference in size between a football stadium and
the coin flipped to start the game. Nothing that we know fills this
size gap, although there must be such objects somewhere in our galaxy.
next twelve orders of magnitude, from 10
cm to 100 cm, bring us from the orbit of Pluto and the edge of the
solar system down to human dimensions. Nearly the same relative
size ratio, from 100 cm to 10,
bridges the span from the size of man down to the size of an atom.
At this point another gap of four orders of magnitude appears, which
separates atoms from atomic nuclei. With nuclei of 10
cm diameter, the lower limit of our known universe is met. We might
suppose subatomic particles to be smaller yet, but have no way of
establishing their size. At the lower limit, as at the upper, scale
in the universe becomes lost in theory.
Our immediately familiar and touchable world ranges from 10
centimeters to 10
centimeters, from the moon to microorganisms. Larger objects such
as stars and galaxies are seen but not always fully comprehended;
smaller objects from the world of molecules and atoms are comprehended
intellectually but seldom seen. We live and work in a midrange of
size between these far extremes. A small protein molecule in a cell
has the same size relationship to us that we have to the sun, and
that the entire solar system has to our galaxy.