The San Francisco call., 1904-06-12
CanOPuS
Is a
Mighty
Star.

n CCAsIoNAL tendency Of the
0hgures used in astronomy to
/strain the faith. Il not the imag-
ination of the technical reader
almost TO the breaking point, is illus
trated by a recent calculation by j. l..
Gore OF the Royal Astronomical Soci-
ETY. concerning the probable mass Of
what. as far as we know at present.
may be regarded as the greatest body
in the universe-the star Canopus.
The magnitude OF conception which
we are required TO form il this case
SO far transcends the ordinary eXer-
cises OF the imagination that it can
only be approached step by step, as
one ascends A mountain by first climb
ing the foothills and its lower but
tresses. Even the Erst step here is
enc from which some minds VIII re-
CoI.
In estimating the relative magni-
tudes Of celestial bodies, the first term
o. comparison IS necessarily the earth
Because We dwell upon the earth we
are able TO get something like real
izinc sense OF its actual size. We can
20 around il in various directions and
can apply a magnified foot rule TO IT,
thus obtaining By direct means the
oata for mental picture OF Slobe
over $4,000 miles in circumference
Yet all do not find IS easy TO form
Sue, n picture and hold it before the
minds eye Il looks more or less
hazy and ~ defined in outline, be-
cause OF the depth of the perspective.
But assuming that you have in your
mind a clear picture OF the earth as
ali astronomical body hanging in
space, first steady yourself by conf
6ently grasDing the hand OF astron-
omy and then. letting the earth so as
after all an inconsiderable trifle, gaze
onward into the far mightier perspec-
tive in the midst Of which hangs the
sun. a body more than million
times larger than the earth.
There are persons not lacking edu-
cation who fatty refuse to believe this.
They prefer TO think that astronom-
ers have made a mistake or COM
mitted some oversight, rather than ac-
cept the statement that the sun. which
does not look very large in the sky
certainly no larger than the moon
IS equal in bulk TO more than a mill
lion earths. Yet of course the fact is
as incontestable as any known to
science. There IS no guesswork
about it.
When you have succeeded, then, in
forming a definite mental picture of
the great globe of the sun, you are
ready for the final flight of imagina-
ton, which Mr. Cores calculation,
based upon authentic astronomical
data, demands that you make if you
hope to understand the scale on
which this universe is built. These
ten words sketch the magnitude of the
conception now required of you;
"Canopus is a million times more
massive than the sun
As much as the sun exceeds the
earth. so much Canopus exceeds the
sun. In each case the multiplication is
= million. A single unit stands for the
earth; a million units represent the
sun; a million times a million units
denote Canopus. Yet Csnopus is also
2 sun: at least We do not know what
else TO call II. But what 4 SUM-
It viii be observed that the compari-
son between the sun and the earth is
based on their relative size, or volume,
while for the sun and Canopus it re
lates 10 their mass, or quantity of mat
ter. This. however. does not essentially
affect the stated inequality. Another
term Tor mass. in everyday life. is
weight. We say that two bodies which
weigh the same are equal in mass. 1t
follows. then. that CanopUs placed in
one scale of a balance would lift mill
lion suns piled together in the other
scale. II the mean density Of CanOpus
is greater than the mean destiny Of the
sun. the former may not be a million
times larger than the latter. But the
probability that there is no great diff
ference Of density, and that we may
say. indifferently. that Canopus ex-
cecds the sun q million times in mass,
or in size.
Fortunate for US that II is not near
by II The earth were as near to that
tremendous star as it is to the sun
that is to say, within about 93 600 900
miles OF its center-this solid globe
could not endure a minute At that dis
tance the blazing orb Of Canopus would
seem TO fill a whole quarter of the
heavens. and the light and heat poured
upon Us would be 10000 times more in
tense than the present radiation of the
sun. The earth would melt and vapo-
rize like a snowflake sucked into the
open door Of A furnace.
The Sravitative or attractive power
OF a globe a million times as massive
rs the sun puts another strain upon
the Imagination.