Data Volume Is Fourth Frontier in Astrophysical Observation Free

Harwit replies: Benjamin Monreal is quite right. Expanding data volumes have had an enormous impact on astronomical discovery. Although my article could not include it, my book Cosmic Discovery (Basic Books, 1981) provides a plot of the eight orders of magnitude improvement over the naked eye, in sensitivity and data gathering rates, made possible by 1980 through increased telescope apertures, more sensitive photo-response, and increasingly large numbers of spatial resolution elements on photographic plates and photoelectric arrays. The recent discovery, by the DENIS and 2MASS all-sky surveys, of a few dozen extremely low-mass brown dwarfs among hundreds of millions of more ordinary stars, shows the added value of machine data processing.