Brian Marsden, astronomer and comet predictor, 73
Brian Marsden passed away on Nov. 18 after a prolonged illness at the age of 73. He was a supervisory astronomer at the Smithsonian Astrophysical Observatory at the Harvard-Smithsonian Center for Astrophysics (CfA). “Brian was one of the most influential comet investigators of the 20th century,” said Charles Alcock, CfA director, “and definitely one of the most colorful!” 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. Such calculations are critical for tracking potentially Earth-threatening objects. The New York Times once described Marsden as a “Cheery Herald of Fear.” The comet prediction of which Marsden was most proud was that of the return of Comet Swift-Tuttle, which is associated with the Perseid meteor shower each August. Swift-Tuttle had been discovered in 1862, and the conventional wisdom was that it would return around 1981. Marsden had a strong...