What Fraction of Papers in Astronomy and Physics Are Not Cited in 40 Years?

Of 4000 papers published in astronomy and in physics in the past 40 years, 40.3%, and 23.4%, respectively, have not been cited (referenced). However, if we limit this to the final research papers (excluding announcements, book reviews, proposals for funding, and observing time, obituaries, etc.), the fractions are 1.4% and 1.5%, respectively. So virtually all the papers in these two sciences are useful. These data also tell us that the productivities of astronomers peak at age 40.4 years. and that 43.0% were published after the age of 50 years. For physicists, the peak occurs at 36.6 years. and only 33.7% were published after the age of 50 years. Therefore physicists peak about four years earlier than astronomers and they produce 9% fewer citations after the age of 50 years. [ABSTRACT FROM AUTHOR]