The Portland daily press., 1892-08-13
Melting of Mars snow-Cap.
New York Herald


The special cable despatch to the
Herald from Professor William H. Pick
ering, director of the Harvard College
Annex Observatory at Arequipa, Peru,
gives our readers this morning an inten-
sely interesting account of recent obser-
vations of the planet Mars taken in the
steady skies of the Andes. which are
highly favorable for telescope work.
Professor Pickering's station is eight
thousand feet above sea level, and hence
its natural advantages are much greater
than even those of the Lick Observatory,
on Mt. Hamilton, California.
Professor Pickering has seen two
large areas near the equator of Mars
which he pronounces permanently blue.
They cover five hundred thousand
square miles of the planet. On June %,
ult, he observed small dark spot in the
southern snowcap, which subsequently
grew rapidly in length, until early in July
it was thousand miles long, dividing
the snow in halves. In thirty days, he
says, sixteen million square miles of
snow have been melted and apparently
transferred across the continents into the
Martial seas.
Such phenomenon is unparalleled in
the physical history of the earth, unless,
perhaps, in the so-called miocene period
of geology. Assuming the accuracy of
Professor Pickering's deduction, astron-
omers will be puzzled to account for
such an extensive liquefaction of the
Martial SHOWS in the short space of
month. If Mars were subject to shot
waves' of equally intensity with those
that have recently visited North America
it would still be difficult to account for
the phenomena recorded by the Arequipa
observers. Even in the Equatorial Andes
at elevations of about twenty thousand
feet the snowfall of winter remains the
year round. But it must be remem-
bered that the supply of solar heat
received by the Mars is much smaller
than that received by the earth. At the
planets nearest approach to the sun it is
still thirty-five millions farther from the
central luminary than we are, and on the
average it receives less than half the
amount of heat and light ON given unit
of surface that the earth receives. We
can hardly, therefore, suppose that vast
area of Martial snow can be speedily dis
solved by ordinary atmospheric waves of
heat.
Despite the fact that it's distance
from the sun is so great as to leave it a
comparatively limited supply of extran-
eous heat, astronomers notice that the
climate of Mars, as Professor Young
says, appears, for some reason not yet
discovered, to be much more mild than
would be expected, and $50 far as we
can judge, the water on the planet is
never frozen except very near the poles"
This anomaly in the Martial climate
might be easily explained if there were
evidences of large supply of aqueous
vapors in its atmosphere. In that case
the heat which it receives from the sun
would escape but slowly into space.
DR.. Higgins has found by spectroscopic
observations that the Martial atmosphere
certainly does contain aqueous vapor.
But no reason, we believe, has been as
signed for inferring that it is as rich in
vapor as the earth's atmosphere.
1t would appear, therefore, that in at
tempting to explain the remarkable
phenomenon observed by Professor
Pickering we are for the present at least,
shut up to the inference that the recent
extensive melting of the south polar
snow-cap of Mars has taken place under
the action of its volcanic fires. Our
south polar regions, though marked by
gigantic volcanoes, as Erebus and Terror
are surmounted by an enormous ice-cap
which apparently for many centuries has
resisted all climatic forces tending to
dissolve it.
The observations at Arequipa which
we print today deserve the most careful
study of physicists as they perhaps
throw more light upon the physical con-
ever before been obtained, unless in the
case of own satellite. 1t is to be hoped
that other observers may be made able to
confirm Professor Pickering's deduc-
tons.