Szilard Crater Honors Hungarian-American Physicist Leo Szilard

Summary: Szilard Crater honors Hungarian-American physicist Leo Szilard, a nuclear pioneer whose Einstein-Szilard letter prompted the U.S. nuclear program.

Detail of oblique, northeast-facing view, obtained during Apollo 16 mission, shows Szilard Crater (center) with Giordano Bruno Crater (upper left corner); ray streaking from Giordano Bruno across Szilard's northwestern rim (upper left) to southeastern rim between Szilard H (bottom right) and Szilard M (center right); and Richardson E (lower left) squeezed between Richardson Crater (lower left corner) and Szilard; NASA ID AS16-M-3008: James Stuby (Jstuby), Public Domain (CC0 1.0), via Wikimedia Commons

The lunar far side’s Szilard Crater honors Hungarian-American physicist Leo Szilard, a nuclear pioneer who authored the Einstein-Szilard letter, signed by theoretical physicist Albert Einstein and sent to U.S. President Franklin Roosevelt, advocating U.S. nuclear development.

Szilard Crater is a lunar impact crater in the lunar side’s northwestern quadrant. The impact-eroded crater displays a rumpled western interior floor. Small and large craterlets pockmark Szilard’s relatively level eastern interior floor.

Szilard is centered at 33.71 degrees north latitude, 105.78 degrees east longitude, according to the International Astronomical Union’s (IAU) Gazetteer of Planetary Nomenclature. The northern hemisphere crater’s northernmost and southernmost latitudes occur at 35.8 degrees north and 31.61 degrees north, respectively. The worn crater obtains easternmost and westernmost longitudes at 108.3 degrees east and 103.26 degrees east, respectively. Szilard Crater’s diameter spans 127.22 kilometers.

Radial streaks of fine ejecta from the ray system centered on northwestern neighbor Giordano Bruno Crater extend across Szilard’s rim and interior. Giordano Bruno is centered at 35.97 degrees south latitude, 102.89 degrees east longitude. The bright crater’s northernmost and southernmost latitudes stretch from 36.33 degrees north to 35.6 degrees north, respectively. Its easternmost and westernmost longitudes are found at 103.34 degrees east and 102.44 degrees east, respectively. Giordano Bruno has a diameter of 35.97 kilometers.

Szilard Crater is classified as a primary crater in the Szilard Crater system. The primary crater parents two proximitous satellites. Szilard H gouges its parent’s southeastern rim. Szilard M perches to the south-southeast of its parent.

Szilard Crater’s west-southwestern named neighbor is Richardson Crater. The large lunar impact crater’s eastern satellite, Richardson E, squeezes between its parent’s eastern rim and Szilard’s southwestern rim.

Richardson Crater participates in a distinctive formation with craters Maxwell and Lomonosov. Maxwell Crater infringes upon southwestern Richardson. Lomonosov overlies southern Maxwell.

The Szilard Crater systems honors 20th-century Hungarian-American physicist Leo Szilard (Leó Szilárd). The International Astronomical Union approved the primary crater’s official name in 1970 during the organization’s XIVth (14th) General Assembly, which was held in the seaside resort of Brighton in South East England from Tuesday, Aug. 18, to Thursday, Aug. 27. Prior to its formal naming, Szilard Crater was designated as Crater 116. Approval of the letter designations for Szilard’s two satellites was given in 2006.

Leo Szilard (Feb. 11, 1898-May 30, 1964) is credited with the joint discovery of a technique for separation of isotopes (chemical element variants differing in numbers of neutrons in each atom) for medical purposes in 1934. Szilard and English physicist Thomas A. Chalmers made their discovery at St. Bartholomew’s Hospital in London, United Kingdom. The method is known as the Szilard-Chalmers effect or process.

Szilard’s interest in nuclear fission chain reactions and his concern over Germany’s nuclear weapon project prompted the Einstein-Szilard letter of Aug. 2, 1939. Szilard collaborated with Hungarian-American theoretical physicists Edward Teller (Jan. 15, 1908-Sept. 9, 2003) and Eugene Paul “E.P.” Wigner (Nov. 17, 1902-Jan. 1, 1995) in writing the letter warning of the development of uranium as a “new and important source of energy” via nuclear chain reactions. “This new phenomenon would also lead to the construction of bombs, and it is conceivable -- though much less certain -- that extremely powerful bombs of a new type may thus be constructed,” the letter warned. The letter was addressed to 32nd U.S. President Franklin Delano Roosevelt (Jan. 30, 1882-April 12, 1945) and was sent with German-born theoretical physicist Albert Einstein (March 14, 1879-April 18, 1955) as the sole signatory.

The takeaways for the lunar far side’s Szilard Crater, which honors 20th-century Hungarian-American physicist Leo Szilard, are that the primary lunar impact crater is located the far side’s northwestern quadrant; that Szilard Crater parents two proximitous satellites, Szilard H and Szilard M; and that the crater’s namesake physicist is credited with the Szilard-Chalmers effect for using isotopes for medical purposes, with pioneering involvement in nuclear chain reactions and with co-authoring on Aug. 2, 1939, the Einstein-Szilard letter urging development of the U.S. nuclear program.

Detail of Shaded Relief and Color-Coded Topography Map shows lunar far side’s Szilard Crater (upper right) and satellites Szilard H (unmarked; side parent, map right) and Szilard M (unmarked; belw parent, map right), with craterlet on M's northwestern rim, in the northwestern quadrant: U.S. Geological Survey, Public Domain, via USGS Astrogeology Science Center / Gazetteer of Planetary Nomenclature

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Detail of oblique, northeast-facing view, obtained during Apollo 16 mission, shows Szilard Crater (center) with Giordano Bruno Crater (upper left corner); ray streaking from Giordano Bruno across Szilard's northwestern rim (upper left) to southeastern rim between Szilard H (bottom right) and Szilard M (center right); and Richardson E (lower left) squeezed between Richardson Crater (lower left corner) and Szilard; NASA ID AS16-M-3008: James Stuby (Jstuby), Public Domain (CC0 1.0), via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Szilard_crater_AS14-75-10306.jpg

Detail of Shaded Relief and Color-Coded Topography Map shows lunar far side’s Szilard Crater (upper right) and satellites Szilard H (unmarked; side parent, map right) and Szilard M (unmarked; belw parent, map right), with craterlet on M's northwestern rim, in the northwestern quadrant: U.S. Geological Survey, Public Domain, via USGS Astrogeology Science Center / Gazetteer of Planetary Nomenclature @ https://planetarynames.wr.usgs.gov/images/moon_farside.pdf

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