Geoscience Reference
In-Depth Information
A Field to Himself
In early 1941, the astrophysicist Ralph B. Baldwin (1912-2010) was an instructor
of astronomy at Northwestern University and on the verge of becoming a father.
In order to support his soon-to-be-enlarged family, Baldwin began to moonlight
by giving lectures at Chicago's Adler Planetarium, for four dollars each. When he
arrived early, he would wander the halls, examining the Adler's exhibits and espe-
cially its superb photographs of the Moon. One in particular caught Baldwin's eye:
it showed a set of “long valleys with raised rims” that he had never seen mentioned
in the literature. He noticed that these valleys “pointed backward toward
Mare Im-
brium
.”
1
Hiscuriosityaroused,BaldwinsearchedthelibraryoftheDearbornObservatory
for an explanation of the strange valleys. Finally he found a paper that attributed
them to “the nearly tangential impact of a swarm of huge meteorites,” a suggestion
that did not strike him as “viable.” As he continued to peer at the photographs,
Baldwin began to reconsider the role of meteorite impact on the Moon: “Could it
be that
Mare Imbrium
was the moon's largest crater and the valleys were splash
craters from debris ejected at the birth of the huge pit? Were there others like
Imbrium
?” Answering his own question, he exclaimed: “There were!
Crisium
,
Nectaris
,
Humorum
,
Serenitatis
and
Humboldtianum
.” Baldwin concluded that
“the circular maria had been produced by gigantic explosions—only the impact of
giant meteorites could supply the requisite energy.”
2
A few weeks after coming to this startling conclusion, the unknown Baldwin at-
tended a colloquium that drew several eminent astronomers. He soon discovered
that none of them knew or cared much about the Moon—his few weeks of study
had left him “knowing far more about the Moon than any of them.” Baldwin real-
ized that “nobody else was actively mining this lode” and that he had “a significant
field almost to himself” (369-370). He wrote up his ideas, titling the paper “The
Meteoritic Origin of Lunar Craters,” and submitted it to leading astronomy journ-
als and to the
Annals of the Dearborn Observatory
. All rejected the article. Fin-
ally
Popular Astronomy
, where T. J. J. See had often published, printed Baldwin's
