Blackfoot news. (Blackfoot, Idaho) 1891-1902, 1898-01-22

! !: ] ]: J ].
- 4
81 SnH~ tronomy-f o m a
ENNA mundane stan d.
SE3 point. At any rate
N are those that
y refer to the earth's
XII own satellite, says
III DR. H s. Williams
in Harper's Maya
zine That seemingly staid body was
long ago discovered to have a pro-
penstty 10 gain a little on the earth.
appearing AZ eelipses an fnfnitesimal
moment ahead of time Astronomers
were sorely puzzled by this act of in,
subordinafions but at last Laplaee
and Lagrange explained II as due to
an oscillatory change in the earth's or
bit. thus fully generating the moon.
and seeming To demonstrate the abb
solute stability and permanence of our
planetary system. which the moons
misbehayior had appeared TO threaten
This highly satisfactory conclusion
was an orthodox belief of celestial me-
chanies until 1853, when Prof. Adams
OF Septunian fame, with whom COM
pick analyses were a psstime. reviewed
Laplace's calculations and discovered
an error which. when corrected. left
about half the moons aceeleration un-
accounted for. This was a momentous
discrepancy which at first no one could
explain But presently Prof. Hem
holtz, the great German psychist, sug-
gested that key might be found in
tidal friction. which, acting as n per-
/ pctuai brake On the earth's rotation,
and affecting not merely the waters.
I but the entire substance of our planet.
/ must in the long sweep of time have
/ changed it's rate of rotation. Thus the
seeming aoceieration of the moon
1 might be accounted for as actual re-
/ tardation of the earth's rotation-a
lengShening of the day. instead Of q
shortening Of the month Again the
earth was shown to be at fault. but
this time the moon could not be ex-
I onerated, while the estimated stability
1 OF our system. instead of being re-es-
/ tablished, was quite upset For the
tidal retRrdstfon is not quite an oscil-
latory change which viii presently
correct itself, like the orbital vabble.
but perpetual change, acting always
in one direction Unless fully coun-
teracted by some opposing reaction
therefore las It seems not to BEL. the
effect must be cumulative, the ultimate
consequences disastrous The exact
character of these consequences was
first estimated by Prof. G. II. Darwin
In 1879. He showed that tidal friction
in retarding the earth must also push
the moon out from the parent planet
on a spiral orbit Plainly then the moon
must formerly have been nearer the
earth than at present At some very
remote period it must have actually
touched the earth; must. in other
words, have been thrown off from the
then plastic mass of the earth, as a
poiyp buds out from its parent polyp
At that time the earth was spinning
about in a day of from two to four
hours Now the day has been length
ened to twenty-four hours and the
moon has been thrust out a distance
OF quarter million miles; but the end
is not yet The same progress OF
events must continue till. at some re.
mote period in the future. the day has
come to equal the month, lunar tidal
; action has ceased. and one face of the
earth looks out always at the moon
with that same fixed stare which ever
now the moon has been brought tt
assume toward her parent orb. Should
we choose to take even greater liber
ties with the future it may be made
to appear Though some astronomer:
dissent from this prediction) that, a
solar tidal action still continues. tn,
day must finally exceed the month an,
: lengthen out little by little toward co
incidence with the year, and that tn
: moon meantime must pause in its out
!, ward flight and come swinging back OIL
. a swinging spiral, until finally, afte
8 the lapse of untold aeons, it plows ant
= ricochets along the surface of tn
: earth and plunges to catastrophe dc
: struction. But even though imagina
0 ton pause far short of this direful cul
mination, it still is clear that moderi
b calculations, based on memorable Il
4 DIAL friction, suffice to revolutioniz
h the views formerly current as to tn
a stability of the planetary system. Tn
. eighteenth century mathematics
3 looked upon this system as vast &C
n lestial machine which had been I
Il existence about 5000 years. and whic
!, was destined to run on forever. tn
!, analyst of today computes both til
: past and the future of this system
millions instead of thousands of year
vet feels well assured that the sofa
system offers no contradiction to thos
laws of growth and decay which seel
everywhere to represent the immu
Ia ahIa order of nature