1893: Grove Karl Gilbert (1843-1918): "The Moon's face, a study of the origin of its features"
Philosophical Society of Washington Bulletin 12.
Gilbert was the Director of the US Geological Survey and a geologist
with much experience in mapping the western states and territories.
Using the Naval Observatory 26.5" refracting telescope in
Washington, DC and photographs from Yerkes Observatory, Gilbert
took a fresh look at the Moon to evaluate the origin of the craters. He
applied geological insight and knowledge to refute the common
assertion that the lunar craters were volcanoes, and concluded - far in
advance of his contemporaries - that they were formed by giant
impacts. Gilbert proposed that the circular maria had ponded within
truly huge impact craters, and he was the first to recognize the
radiating structure around the Imbrium basin, which he named
sculpture. His lunar scientific contributions (as distinct from map
making) rank with those of Galileo, Madler and Baldwin.
Unfortunately, there was little interest in the Moon 100 years ago, and
Gilbert's paper was published in a journal that few astronomers read.
Hence his work was little known nor appreciated until it was
rediscovered in the 1960s.
Ironically, Gilbert's recognition of the overarching role of impacts in
the formation of lunar craters did not prevent him from making a huge
blunder when studying the most impressive impact crater on Earth.
His study of the Arizona feature know as Coon Butte convinced
him it was a volcanic crater, but during the first century of the 1900s
the mining engineer Ninninger convinced himself - and later the world -
that it had a different origin, as reflected in its current name: Meteor
Crater.
The frontispiece for Gilbert's article was this drawing of the crater
Clavius, which he used to illustrate that younger and typically smaller
craters occurred on and within larger craters.
The most famous diagram from Gilbert's paper is this one illustrating
the "Imbrium Sculpture" that radiates from the giant Imbrium impact
basin.
