Catching a galaxy in the making isn’t easy. It requires a great deal of cleverness and years of diligent searching. As a graduate student at the University of California at Berkeley in the mid-1980s, Mark Dickinson did not mind the hard work. He was one of the few astronomers lucky enough to be engaged in mapping the universe’s farthest frontier, the region billions of light-years away where galaxies appear to be frozen in their infancy in the distant past. It was a frustrating business, but also rewarding: understanding how galaxies were created is as important to astronomers as deciphering the origin of species is to biologists.
It could take hours or even several nights at the telescope to obtain just one good candidate, recalls Dickinson. That’s because he and his fellow observers were fighting the limits of their instrumentation. Given the time it takes light from a galaxy at the far end of the universe to reach Earth, the farther they peered into the depths of space, the farther they also saw into the past. The trouble was, they couldn’t see very much. Galaxies that resided more than a mere couple of billion light- years away were dim, fuzzy, and next to impossible to identify. There, wrote astronomer Edwin Hubble in 1936, we measure shadows and . . . search among ghostly errors of measurement for landmarks that are scarcely substantial. Astronomers have tried tracing the evolution of galaxies through those shadowy eons ever since, with little success.
But no longer. The trickle of data that distant-galaxy hunters once collected has now turned into a veritable geyser. Thanks to several key technological breakthroughs--the opening of the giant Keck telescope on Hawaii’s Mauna Kea in 1992, the improved vision of the Hubble Space Telescope, and advances in telescopic detectors--hundreds of young galaxies have now been sighted, with more being found each day. The early cosmos is fast becoming quite familiar. Says Dickinson, who now studies the far universe at the Space Telescope Science Institute, Since I’m used to scrabbling at the edge, I’m tempted to move on to something more murky.
