last digit in Pu-239, the weapon-grade fissile isotope used in nuclear bombs. In astronomy Messier object M49 , a magnitude 10.0 galaxy in the constellation Virgo . The New General Catalogue [http://www.ngcic.org/ object] NGC 49 , a spiral galaxy in the constellation Cetus . The Saros [http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros1-175.html number] of the solar