Brian Geoffrey Marsden (5 August 1937 Cambridge, England – 18 November 2010 Burlington, Massachusetts, US)[1] was a British astronomer born in Cambridge, England, and educated at The Perse School in Cambridge, New College, Oxford and Yale University. Dr. Marsden was the longtime director of the Minor Planet Center (MPC) at the Harvard-Smithsonian Center for Astrophysics (director emeritus from 2006 to 2010).[2]
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Marsden specialized in celestial mechanics and astrometry, collecting data on the positions of asteroids and comets and computing their orbits, often from minimal observational information and providing their future positions on International Astronomical Union (IAU) circulars. In addition to serving as MPC director since 1978, he served as the director of the Central Bureau for Astronomical Telegrams (CBAT) from 1968 to 1999.[3] He was president of Commission 6, and Commission 20 of the IAU.[4]
Marsden helped recover once lost asteroids and lost comets. Some asteroid and comet discoveries of previous decades were "lost" because not enough observational data had been obtained at the time to determine a reliable enough orbit to know where to look for re-observation at future dates. Occasionally, a newly discovered object turns out to be a rediscovery of a previously lost object, which can be determined by calculating its orbit backwards into the past and matching calculated positions with the previously recorded positions of the lost object. In the case of comets this is especially tricky because of nongravitational forces that can affect their orbits (one of which is emission of jets of gas from the comet nucleus), but Marsden has specialized in calculating such nongravitational forces. Notably, he successfully predicted the 1992 return of the once-lost Comet Swift-Tuttle.
In 1998, he calculated that an asteroid, (35396) 1997 XF11 might strike the Earth in 2028. Marsden chose to issue a press release, which Robert Roy Britt called a false alarm.[5]
Other asteroid researchers called it a "mistake" and Marsden himself admitted the announcement was a strategy which needed "rethinking", and NASA asked astronomers not to sound a public alarm like that again but to communicate with each other.[6] He took some criticism for publicizing this prediction right when movie companies were publicizing films like "Deep Impact" (see also Science by press conference). However, Marsden justified his actions with the argument that the problem of detecting asteroids needs more attention:
Follow-up work determined that an impact would be unlikely.[8]
He once proposed that Pluto should be cross-listed as both a planet and a minor planet and assigned the asteroid number 10000; however, this proposal was not accepted. A similar proposal was, however, finally accepted in 2006 when Pluto was designated minor planet 134340 and also declared a dwarf planet.
| 37556 Svyaztie | August 28, 1982 | with N. S. Chernykh |
He married Nancy Lou Zissell; they had a daughter, Cynthia, and a son, Jonathan.[8]
Awards
Named after him