burns to vapor in the earth's upper atmosphere. And
if one tiny planet sweeps up such masses of this cosmic
matter, the amount of it in the entire stretch of our system
must be beyond all estimate. What a story it tells
of the myriads of cometary victims that have fallen
prey to the sun since first he stretched his planetary net
across the heavens!


THE FIXED STARS

When Biela's comet gave the inhabitants of the earth
such a fright in 1832, it really did not come within
fifty millions of miles of us. Even the great comet
through whose filmy tail the earth passed in 1861 was
itself fourteen millions of miles away. The ordinary
mind, schooled to measure space by the tiny stretches
of a pygmy planet, cannot grasp the import of such
distances; yet these are mere units of measure compared
with the vast stretches of sidereal space. Were
the comet which hurtles past us at a speed of, say, a
hundred miles a second to continue its mad flight unchecked
straight into the void of space, it must fly on
its frigid way eight thousand years before it could
reach the very nearest of our neighbor stars; and even
then it would have penetrated but a mere arm's-length
into the vistas where lie the dozen or so of sidereal residents
that are next beyond. Even to the trained mind
such distances are only vaguely imaginable. Yet the
astronomer of our century has reached out across this