Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1873-08-28
The Warm Full Moon.

The Warm Full Moon.
POETS have SO long sung of the cold,
chaste moon, pallid with WEAKNESS of her
long watch upon the earth according to
the image used alike by Wordsworth and
Shelley that it seems strange to learn
from science that the full moon is SO in
tensely hot that no creature known to us
could long endure contact with her heated
| surface. Such is the latest news which
+, science has brought us respecting our
satellite. The news is not altogether un-
expected; in fact, reasoning had shown,
| long before the fact had been demonstrate
ed, thai it must be so. The astronomer
knows that the surface of the moon is
exposed during the long lunar day, last
ing a fortnight OF our terrestrial time to
the rays of sun as powerful as that
which gives us our daily heat. Without
an atmosphere to temper the suns heat as
ours does-not indeed, by impeding the
| passage OF the solar rays, but by bearing
| aloft the cloud-veil which the sun raises
from our oceans-the moons surface must
become intensely hot long before the mid
want OF an atmosphere causes the moons
heat to be rapidly radiated away into
| space. 1t is our atmosphere which causes
steady heat to prevail on our earth. And
at the SUBMITS of lofty mountains, where
| the atmosphere is rare, although the mid
| day heat is intense, yet so rapidly does the
| heat pass away that snow crowns forever
| the mountain heights Yet although the
moons heat must pass away even more
rapidly, this does not prevent the heating
| of the moons actual surface any more
than the rarity of the air prevents the
Alpine traveller from feeling the action of
| the suns direct heat even when the air in
shadow is icily cold. Sir John Herschel
long since pointed out that the moons
surface must be heated at lunar midday
to degree probably surprising the heat
OF boiling water. p, ,
Such, in POINT Of fact, has now been
proved to be the case. The Earl Of Rosse
has shown by experiments which need
not here be described that the moon not
only reflects heat to the earth (which, of
course, must be the easel, but that she
gives out heat by which she has been her
self warmed. The distinction NAV not
perhaps appear clear at first sight to eve
ry reader but it may easily be explained
and illustrated. If, on bright summers
day, we take a piece of smooth but not too
we'll polished metal, and by means of it
reflect the suns light upon the face, a SEN
satlon of heat will be experienced This
IS reflected sun-heat. But if we wait
while so holding the metal until the plate
has become quite hot under the solar rays,
we shall recognize sensation Of heat
from the mere proximity Of the plate to
the face, even when the plate is so held as
not to reflect sunheat. We can in sue
cession try-tirst, reflected heat alone be
fore the metal has grown hot; next, the
heat which the metal gives out of itself
when warmed by the suns rays; and
lastly, the two kinds of heat together,
when the metal is caused to reflect sun
I heat, and also being held near the face)
to give eut-a sensible quantity of its own
warmth. What Lord Rose has done has
been to show that the full moon sends
earthward both kinds of heat; she reflects
solar heat Just as she reflects solar light,
and she also gives out the heat by which
her own surface has been warmed
1t may perhaps occur to the reader to
inquire how much heat we actually OBJ
tain from the full moon. There is sim
pie way of viewing the matter. If the
I full moon were exactly as hot as boiling
water We should receive from her just as
much heat Qeaving the effect of our at
mOSphere out OF accounts as we should re-
CeVe from a small globe as hot as boiling
water, and at such a distance as to took
| Just as large as the moon does. Or disk
| Of metal would serve equally we'll The
| experiment may be easily tried. An old
! fashioned penny is just one inch in diam
| eter, and as the moons average distance
| is about Ill times her own diameter,
| penny at a distance Of III inches, or three
| yards and three inches, Looks just as large
as tie moon. Now let a penny be put in
boiling water for a while, so that it be
comes as hot as the water; then that coin,
taken quickly and set three yards from
the observer, will give out for the few mo-
ments that its heat remains appreciably
| that Of boiling water, so much heat to the
observer as he receives from the full moon
supposed to be as hot as boiling water.
Or globe of thin metal one inch in d-
ameter, and full of water at boiling heat,
would serve as a more constant artificial
moon in respect of heat-supply. 1t need
not be thought remarkable then, if the
heat given out by the full moon is not
easily measured, or even recognized. I'm
agne how little the cold Of winters day
would be relieved by the presence in a
room not otherwise warmed Of a Oneinch
globe Of boiling water three yards away
And, by the way, we are here reminded of
an estimate by Professor c. p Smyth re
sulting from observations made on the
moons heat during his Teneritfe expert
ments He found the heat equal to that
emitted by the hand at distance Of three
feet
But, after all, the most interesting re-
suits flowing from the recent researches
are those which relate to the moon her
self. We cannot but speculate on the
condition of world SO strangely circum-
stanced that a cold more bitter than that
OF our Arctic nights alternates with heat
exceeding that Of boiling water 1t is
strange to think that the calm-looking
moon is exposed to such extraordinary
vlcissitudes. There can scarcely be life
in any part of the moon-unlcss it be I'M
foreground life, like that of the Modoc
Indians I'VE commend this idea specially
| to the more ardent advocates of Brew
sterian ideas respecting other worlds than
| ours). And yet there must be singular
~ active mechanical progress at work in
yonder orb. The moons substance must
expand and contract marvelously as the
alternate waves Of heat and cold pass over
1t. The material Of that cratercovered
surface must be positively crumbling
away under the effects of these expansions
| and conuactions. The most plastic ter
restial substances could not long endure
such processes, and it seems altogether
| unlikely that any part Of the moons crust
| Is at all plastic. Can we wonder if from
time to time astronomers tell US of appar-
! emf ch3nTpS in the ,Ual1