Szilard Crater Parents Two Satellites on Lunar Far Side

Summary: Szilard Crater parents two satellites on the lunar far side in the crater jumble northeast of the northwestern quadrant’s Mare Marginis.

Details of Lunar Astronautical Charts (LAC) 29 (left), 30 (right) and 46 (below) show the Szilard Crater system of parent Szilard and satellites H and M in the lunar far side’s northwestern quadrant; courtesy NASA (National Aeronautics and Space Administration) / GSFC (Goddard Space Flight Center) / ASU (Arizona State University): U.S. Geological Survey, Public Domain, via USGS Astrogeology Science Center / Gazetteer of Planetary Nomenclature

Szilard Crater parents two satellites on the lunar far side in the crater jumble northeast of Mare Marginis (Sea of the Edge) in the northwestern quadrant.

The Szilard system’s primary crater 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 registers northernmost and southernmost latitudes of 35.8 degrees north and 31.61 degrees north, respectively. The impact-eroded crater records easternmost and westernmost longitudes at 108.3 degrees east and 103.26 degrees east, respectively. Szilard Crater’s diameter measures 127.22 kilometers.

Parental Szilard is credited with two satellites. Szilard H makes an inward bulge on its parent’s southeastern rim. Szilard M neighbors near its parent’s south-southeastern rim.

Szilard H is centered at 32.65 degrees north latitude, 108.23 degrees east longitude. H’s northernmost and southernmost latitudes occur at 33.46 degrees north and 31.84 degrees north, respectively. The satellite obtains easternmost and westernmost longitudes at 109.19 degrees east and 107.26 degrees east, respectively. Szilard H’s diameter spans 49.25 kilometers and equates to approximately 40 percent of its parent’s diameter.

Szilard M features a craterlet on its northwestern rim. Szilard M is centered at 31.25 degrees north latitude, 106.71 degrees east longitude. M posts northernmost and southernmost latitudes at 31.64 degrees north and 30.85 degrees north, respectively. The satellite marks easternmost and westernmost longitudes at 107.18 degrees east and 106.25 degrees east, respectively. With a diameter of 24.06 kilometers, Szilard M qualifies as the smaller of the Szilard Crater system’s two satellites.

Mare Marginis (Sea of the Edge) lies to the southwest of the Szilard Crater system. The lunar mare wraps around the lunar near side’s eastern limb in its occupancy of both sides of the moon.

Mare Marginis is centered at 12.7 degrees north latitude, 86.52 degrees east longitude. The northern hemisphere lunar mare’s northernmost and southernmost latitudes stretch from 18.59 degrees north to 9.81 degrees north, respectively. The irregularly shaped, dark basaltic plain’s easternmost and westernmost longitudes reach 93.35 degrees east and 81.15 degrees east, respectively. Mare Marginis has a diameter of 357.63 kilometers.

Szilard Crater and its two satellites are named in honor of Leo Szilard (Feb. 11, 1898-May 30, 1964). The 20th-century Hungarian-American physicist numbered among the World War II era’s (Sept. 1, 1939-Sept. 2, 1945) pioneers of nuclear fission and of the nuclear chain reaction.

The Szilard Crater system’s location to the east-northeast of the lunar far side’s Maxwell Crater makes neighbors of Leo Szilard’s namesake crater and the crater named after the hypothesizer of Maxwell’s demon, the subject of Szilard’s doctoral dissertation at Friedrich Wilhelm University (German: Friedrich-Wilhelms-Universität) in Mitte, central Berlin, Germany. Nineteenth-century Scottish mathematical physicist James Clerk Maxwell (June 13, 1831-Nov. 5, 1879) had conceived Maxwell’s demon as a thought experiment illustrating a possible contradiction of the second law of thermodynamics’ statement of thermodynamic equilibrium. (Thermodynamics is the branch of physics concerned with relations between heat, energy and matter.)

Szilard’s intellectual fascination with nuclear fission chain reactions and his concern over Germany’s nuclear weapon project motivated the Einstein-Szilard letter. German-born theoretical physicist Albert Einstein (March 14, 1879-April 18, 1955) addressed the Aug. 2, 1939, letter to 32nd U.S. President Franklin Delano Roosevelt (Jan. 30, 1882-April 12, 1945). In actuality, the text of the letter was drafted by Szilard and Hungarian-American theoretical physicists Edward Teller (Jan. 15, 1908-Sept. 9, 2003) and Eugene Paul “E.P.” Wigner (Nov. 17, 1902-Jan. 1, 1995). The letter urged the development of a U.S. nuclear program.

Despite his critical involvement in nuclear development, Szilard was sensitive to nuclear weaponry’s unparalleled, seemingly limitless destructiveness. Thus, on July 17, 1945, Szilard drafted A Petition to the President of the United States, known as the Szilárd petition. The document, addressed to 33rd U.S. President Harry S. Truman (May 8, 1884-Dec. 26, 1972), was signed by Szilard and 69 scientists working on the Manhattan Project at the University of Chicago’s Metallurgical Laboratory in Chicago, Illinois. The Szilárd petition, which did not reach its addressee, urged against the use of atomic bombs against Japan.

In 1961, Simon and Schuster published The Voice of the Dolphins, a book of six, Cold War-themed short stories by Szilard. The title story’s international biology research laboratory, set in Central Europe, inspired the establishment of the European Molecular Biology Laboratory (EMBL) in 1974. The intergovernment organization comprises six sites: Heidelberg, Baden-Württemberg, southwestern Germany; Hinxton, Cambridgeshire, East England; Grenoble, Auvergne-Rhône-Alpes, southeastern France; Hamburg, northern Germany; Rome, Lazio region, central Italy; and Barcelona, Catalonia, northeast Spain. The international research laboratory’s Szilárd Library, named in honor of Leo Szilard, is housed in EMBL’s main site in Heidelberg.

The takeaways for Szilard Crater’s parentage of two satellites on the lunar far side are that Szilard H gouges its parent’s southeastern rim; that Szilard M neighbors near its parent’s south-southeastern rim; that a large craterlet on the northwestern rim distinguishes Szilard M; that, with a diameter approximating 40 percent of its parent’s diameter, Szilard M is the larger of the system’s two satellites; and that the Szilard Crater system honors 20th-century Hungarian-American physicist and nuclear pioneer Leo Szilard.

Detail of Shaded Relief and Color-Coded Topography Map shows Szilard Crater system (upper right) and northwestern neighbor Maxwell Crater (upper center) in crater jumble northeast of Mare Marginis (lower left corner) in the lunar far side’s 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:

Details of Lunar Astronautical Charts (LAC) 29 (left), 30 (right) and 46 (below) show the Szilard Crater system of parent Szilard and satellites H and M in the lunar far side’s northwestern quadrant; courtesy NASA (National Aeronautics and Space Administration) / GSFC (Goddard Space Flight Center) / ASU (Arizona State University): U.S. Geological Survey, Public Domain, via USGS Astrogeology Science Center / Gazetteer of Planetary Nomenclature @ https://planetarynames.wr.usgs.gov/images/Lunar/lac-29_wac.pdf; https://planetarynames.wr.usgs.gov/images/Lunar/lac-30_wac.pdf; and https://planetarynames.wr.usgs.gov/images/Lunar/lac-46_wac.pdf

Detail of Shaded Relief and Color-Coded Topography Map shows Szilard Crater system (upper right) and northwestern neighbor Maxwell Crater (upper center) in crater jumble northeast of Mare Marginis (lower left corner) in the lunar far side’s 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

For further information:

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Available @ https://planetarynames.wr.usgs.gov/Feature/5799

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Available @ https://planetarynames.wr.usgs.gov/Feature/13351

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Available @ https://planetarynames.wr.usgs.gov/Feature/13352

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