A Trivial Process - Four Revolutions in the Earth Sciences - page 143

crashed. By this time, Gene Shoemaker was a member of the Ranger team at the
Jet Propulsion Laboratory. Ranger got off to an embarrassing start. By 1964 the
first five attempts had failed on launch, missed the Moon, or crashed onto the hid-
den far side. OnJanuary 20, Ranger 6 had a perfect flight to the Moon,but its cam-
eras failed. Then came Ranger 7 , which on July 28, 1964, had a flawless launch
and insertion into the trajectory that would take it to the Moon. Three days later
the craft reached within six hundred miles of the Moon, the distance at which an
engineer was scheduled to turn on its cameras. Soon the announcer proclaimed,
“We have video.” The roomful of staid, pocket-protected JPL engineers “jumped
up and down,” as Shoemaker would remember. 4 Before it crashed, Ranger 7 sent
more than 4,300 images back to Earth.
In anticipation of the information that was about to arrive, in 1964 scientists
put on two conferences. “The Dynamics of the Earth-Moon System,” held at the
Institute for Space Studies in New York City in January included several talks
on the origin of the Moon. 5 The second conclave took place in May at the New
York Academy of Sciences. Titled “The Geological Problems in Lunar Research,”
it dealt mainly with the Moon's surface features, particularly the origin of lunar
craters and their possible relationship to terrestrial impact craters, if indeed there
wereanyimpactcratersinthesolarsystem. 6 Astheconvenerofthesecondconfer-
ence summed up, in spite of the “numerous great technological forces [that] have
been focused on lunar problems . . . we are still in doubt” about the nature of the
Moon's surface. 7 That claim did not reflect the attitude of most of the speakers,
who were not at all in doubt. For generations, “selenologists” had been certain that
most if not all of the Moon's surface features are volcanic.
Jack Green, a long-time proponent of lunar volcanism and a former student of
Walter Bucher's, made two presentations. In the first, he criticized those who over
the years had made overly dogmatic declarations about the Moon. 8 In the second,
he immediately made the dogmatic declaration that meteorite impact is a “trivial
process in affecting both the genesis and development of almost all major lunar
surface structures.” 9 Another speaker titled his paper “Proof of the Volcanic Ori-
gin of Most Lunar Craters and Tectonic Maria.” 10 He announced that “the circular
structures of the lunar crust from the smallest to the largest can be interpreted with
ease by the volcanic theory. Very few phenomena, if any, and at best only the very
smallest among them, can be explained by the impact theory.” 11
One speaker, Ralph Baldwin, begged to differ. In 1949, he had published a topic
that inspired the generation of scientists who would plan the voyages to the Moon
of the 1960s, including Shoemaker. 12 In The Face of the Moon , Baldwin claimed
that not only had impact been the dominant force on the Moon but that a giant col-