Grimaldi, Francesco Maria

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Grimaldi, Francesco Maria

(fränchās`kō märē`ä grēmäl`dē), 1618?–1663, Italian physicist and mathematician. A Jesuit and professor at Bologna, he studied in detail and named the dark areas on the moon. Noted for his discoveries in the field of optics, he was the first to describe the diffraction of light (in a posthumous work published 1665) and the first to attempt a wave theory of light.
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Grimaldi, Francesco Maria


Born Apr. 2. 1618, in Bologna; died there Dec. 28, 1663. Italian physicist and astronomer; professor of mathematics at the Jesuit college in Bologna.

In his Physicomathematical Treatise on Light, Colors, and the Rainbow (published posthumously in 1665), Grimaldi gave a description of the diffraction of light, a phenomenon that he discovered. In his opinion, diffraction is caused by the appearance of waves in a luminous fluid striking the edges of an obstacle—that is, Grimaldi’s notions of light contain the rudiments of the wave theory of light. In collaboration with the Jesuit G. B. Riccioli, he compiled a map of the moon and introduced names for lunar formations that have been preserved to this day. He was an adversary of the heliocentric system and had a hand in drafting the Riccioli treatise directed against Copernicus.


Physico-mathesis de lumine, coloribus et iride. Bologna, 1665.


Ronchi, V. “L’ottica del P. Francesco Maria Grimaldi.” Bollettino di geodesia e scienze affini, 1955, vol. 14, no. 1.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.