SCARS ON THE SHIELD: CARLYLE BEALS, PETER MILLMAN, AND THE BEGINNING OF THE CANADIAN METEORITE CRATER PROGRAM, 1950–1960.

When Peter Millman, an astronomer at the Dominion Observatory in Ottawa, read Ralph Baldwin's 1949 book The Face of the Moon, he excitedly brought it to the attention of the Observatory's recently-appointed Director, Carlyle Beals. Baldwin's book argued that the Moon's numerous circular features were not of volcanic origin, but were due to meteorite impacts, and that the Earth should similarly have an abundance of meteorite impact scars. Beals and Millman decided to test Baldwin's arguments, and Beals initiated an innovative program at the Observatory to search for meteorite craters on the Canadian Shield. By the mid-1960s, ten craters had been discovered in Canada. Today, 190 meteorite craters have been confirmed worldwide, with nearly one-sixth of them in Canada. Investigations of the Canadian craters, employing gravity, magnetic, seismic, and diamond drilling studies, became a model for all future crater studies, and brought international attention to Canadian scientists. [ABSTRACT FROM AUTHOR]