Sky and Telescope - July 2018 - 32
Seeing Is Believing
the oppositions of 1877 and 1892. Many reports by other
observers at the time described these canals, and discussions
ﬂourished as to their nature and difﬁculty or ease of detection, as well as speculation that many canals appeared now
appeared as pairs! Although some of Schiaparelli's contemporaries eagerly conﬁrmed claims of new and double canals,
controversy began to emerge, particularly as new and larger
telescopes came on line.
Canals: Natural or Artiﬁcial?
scientiﬁc grounds - namely, that God would not have created
anything in the universe without purpose. Advocates of this
doctrine included prominent astronomers such as Christian
Huygens, William and John Herschel, and Isaac Newton.
In the late 1800s, there was probably no stronger advocate
for extraterrestrial life than the proliﬁc French author and
astronomer Camille Flammarion. His massive 1862 tome La
pluralité des mondes habités provides an imposing overview of
humankind's place in the universe in relation to presumptive
inhabitants of other worlds, all within an optimistic philosophic and spiritual setting.
It is most revealing in this regard to read Flammarion's
reports on the 1894 opposition of Mars in L'Astronomie. He
comments on some exciting new observations, such as sudden
ﬂashes of brightness along the planet's terminator reported
by several notable observers, including Edward Holden at Lick
Observatory, Percival Lowell, Flammarion himself, and Greek
astronomer Eugène Antoniadi. Copious discussion followed
as to whether these ﬂashes were reﬂected sunlight off mountaintops, clouds, auroras, or even intentional signals by the
Martians themselves. A review in the prestigious English journal Nature that same year included the following statement:
"If we assume the light to be on the planet itself, then it must
either have a physical or human origin; so it is to be expected
that the old idea that the Martians are signaling to us will be
revived." It seems most likely that conjectures like this inspired
H. G. Wells's classic 1897 novel The War of the Worlds.
After Schiaparelli's 1877 announcements of extensive networks of canali on Mars, a virtual race ensued among others
to glimpse, analyze, and classify them. In 1879 he published
a second chart of Mars showing an increasingly detailed network of canali, many narrower and more delicate in appearance than depicted in 1877. Flammarion enthusiastically
wrote about this in La planète Mars and L'Astronomie between
J U LY 2 0 1 8 * S K Y & T E L E S C O P E
The illustrious Director of the Milan Observatory - as
skillful in observation as in calculation - to whom Science
owes more than one brilliant discovery . . . undertook studies
of Mars which were more successful and more fruitful than
any previously undertaken, and which eclipsed those of all his
The debate really heated up after Lowell published his 1894
observations and those of subsequent oppositions, showing
incredibly ﬁne and complex networks of canals and their
putative intersection points or "oases." His most controversial
theories about "intelligent creatures, alike to us in spirit but
not in form," were outlined in each of his books on the Red
Planet. Lowell's contention was that the canals, as seen from
Earth, were not just waterways but agricultural zones fed by
water from the planet's polar caps.
Although Schiaparelli believed that Mars bore life, he was
less convinced the canali were artiﬁcial. In his 1893 book La
vita sul pianeta Marte, he states:
Rather than true channels in a form familiar to us, we must
imagine depressions in the soil that are not very deep, extended
in a straight direction for thousands of kilometers, over a width
of 100, 200 kilometers and maybe more. I have already pointed
out that, in the absence of rain on Mars, these channels are
probably the main mechanism by which the water (and with it
organic life) can spread on the dry surface of the planet.
BONESTELL PAIN TING: REPRODUCED COURTESY OF BONESTELL LLC;
SLIPHER IM AG ES: E A RL C. SLIPHER; M A RS: N ASA / ESA / HUBBLE HERITAG E TE A M
p LINGERING BELIEF While most astronomers came to doubt their
existence, belief in Martian canals lasted until the mid-20th century.
Space artist Chesley Bonestell produced this view of a water-filled canal
stretching away from one of the planet's polar caps for Willy Ley's 1949
book The Conquest of Space.
By the time Percival Lowell arrived on the astronomical
scene in 1894, the canal debate was in full swing. That year
respected astronomer E. E. Barnard, using the new 36-inch
refractor at Lick Observatory, stated that he could not verify
Schiaparelli's contiguous linear canals. Even under the best
seeing conditions, he saw them as irregular, broken features.
Ironically, during that same opposition Eugène Antoniadi was
working with Flammarion at his observatory in Juvisy-surOrge using a 240-mm (9.45-inch) refractor and recorded no
less than 39 of Schiaparelli's canali.
Other observers in France, Germany, England, and Italy
reported numerous canals, many of them double. Such conﬁrmatory reports were no doubt more reﬂective of the high
esteem in which Schiaparelli was held than of a truly objective evaluation of his claims. This was amply demonstrated in
Flammarion's introduction to Schiaparelli's observations of
the 1877 opposition: