Outrageous Hole

The College got a little reflected glory last fall when astronomers were stunned by a discovery made with the help of the McGraw-Hill Observatory telescope on Kitt Peak, Arizona. McGraw-Hill, which is operated jointly by the University of Michigan, M.I.T., and Dartmouth, was one of three observatories from which the biggest void ever identified in outer space was discovered. The observations were made by a team of astronomers, one of whom was Michigan's Robert Kirshner, currently the director of the McGraw-Hill consortium.

Dartmouth Delo Mook explained that the team, in surveying the known galaxies, was measuring the distances to them along lines of sight in order to make a three-dimensional map of space beyond our own Milky Way galaxy. "We know that galaxies occur in clusters, with spaces in between," said Mook, "but what the team found was an outrageous hole up there, a stupendous gap without anything in it."

The void is estimated to be 300-million light years wide, five times the size of any previously encountered hole in space. Kirshner calls it "a significant chunk of the universe" and suggests holding a garbagecan lid overhead at arm's length to block out a region of the sky about the size of the newly discovered void. The discovery calls into question a current theory known as the cosmological principle, according to which the distribution of matter and motion in the universe has on the average the same density in all directions.

"We're still babes in the woods where astronomy beyond our own galaxy is concerned," said Mook. "After all, it was not until the twenties that people were sure there were such things as galaxies. Sixty years ago, we still thought the Milky Way was it." He speculates that with the advent of the space telescope and observations above our atmosphere, other equally startling things will turn up out there.