The Washington herald., 1922-07-23

Scientific
a@N0feg
a1zzAzeyZ4.
N::9hg3,
SUNDAY. JULY "A, Iszz

bUNDArs JULY .. liza
THE BIG DIFFER
LOOKS COOL ToNIGHr
The Big Dipper. the bright De-
sign IN seven stars which has SUCH
cooling suggestion these ho<
nights. is. like many familiar thinr.s
looked at with unseeine eyes. Evsry
one IN the Northern Hemisphsrs
from epoonine youth TO tried old
age. knows this bright star sroun.
There are not 30 many. however,
that know that I've Of these steady
looking bright lights are spesdins
away from the others. ana thas
these i've belong TO q great moving
cluster OF stars known as the Urxs
Major or Big Bear cluster.
THE cluster. which consists Of a
least thirteen stars. has the form
OF a disk about fifteen Iight-years
in thickness and $50 lisht-yesrs
in diameter. II is hard TO realize
what that means. A nght-yesr 10
the distance that light travels IN
one year. The velocity Of lieht
is practically instantaneous. Iss.-
900 miles per second In one day
there are $1,000 seconds Figure
for yourself how far light travels
in $50 years; that 10 the diameter
of the Big Bear.
Sirius, the brightest star IN the
heavens. which is only eight and a
half nght-years from the collar
system. Is also a member Of this
cluster. as 10 also Beta AuriEae, the
bright star in the constellation OF
Aur!ga which is visible in the win
ter to the north Of Orion. This star
Is one hundred and thirty light
years distant. and the five stars
in the Big Dipper which are mem
bers Of the cluster are about sew
enty-five light-years distant from
the earth. 1t may seem strange
that stars SO widely separated as
the stars in the Big Dipper, Sirius
and Beta Aurigae should all be
members OF one connected group,
but this apparently great sepsra-
ter is an effect Of the nesrness OF
the solar system TO the principal
plane OF the cluster. II Instead OF
being almost IN the midst OF this
cluster we were at q distance OF
several hundred light-years from
IT, IL would appear TO US as q small
compact group Of faint stars sirn.-
lar in appearance 70 the Pleiades
fha N-ehu>aE
ades in Taurus.
The etar at the end Of the han
die Of the Big Dipper and the star
farthest from II in the bowl are
not members Of this cluster, and
as they are moving in another d.
rection through space the distinc-
tive form Of the Big Dipper Will
in time be lost. But that fact need
not greatly disturb US. for many
centuries will pass before etsr-
oritt viii destroy our lonR-cher-
ished Big D'pper Many genera
tions TO come will admire this heir
loom Of the heavens studded with
celestial gems that has been handed
down 10 the present generations
from the early days Of recorded
history. Just as we admire Il today
AA-sAaNu bs AAlIFs
The stars in the bowl os ,ha pIr
Dipper form the body and the stars
In the handle form the tail OF Jrsa
Major. the Great Bear. The head
and paws Of the bear are formed
by faint stars lying to the west
and south Of the seven bright stars
Our Bg Dipper. then. is but a por-
ton OF the far more extensive CON
a 80
Little Dipper with the pole-star,
Polaris. at the end Of the handle
similarly outlines the body and tai
/ OF Crss NJ nor. the Lesser Bear.
| Both OF these considerations we
viii now find conspicuously ia view
IN the early evening in the north
and northwest.
Al this time Of year when 50
many are camping out or hiking IN
unfamiliar REGIONS IL is well 70 bear
IN mind q fact which should be
Wen known 70 everyone. that the
Pointers Of the Big Dipper. as the
two stars in the bowl farthest from
the handle are called. point insai-
llhly TO the true north. An irnagi-
nary line through these two stars
extended upward from the bowl 70
distance about equal TO the length
Of the Big Dipper brings Us T. the
pole-star at the end Of the handle
OF the Little D'pper. Anyone
abroad at night in an unfamiliar
country might find Il Of great serv-
Ice 70 have these friendly guides
among the stars-Bv Isabel VI.
Lewis. of the U. s. Naval Observa-
tory.
The longest continuous series OF
annual weather records known are
the rings in the big trees ofrcsli-
fornia, dating back as much as
$500 years
Examination Of the foss1 skull
OF the Rhodesian man shows that
that prehistoric individual suffered
from tooth trouble and earache.
Female crtckets, gr1sshoppers and
katydids are dumb.