18. From Outer Space To Inner        Space   Previous PageNext Page
       Scale in the Universe

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.

The 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.

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