Chances are, you’ve never met Brent Tully, and yet he knows exactly where you live. Better than you do, in fact — and probably better than anybody else in the world. Working at the University of Hawaii’s Institute for Astronomy, he has spent decades researching the locations and distributions of galaxies across deep space. Oh sure, if you just want your location in a city, your phone’s GPS can do that. But if you want to find your address in the universe as a whole, Tully is your go-to guy.
In terms of what he does and why he does it, Tully falls in with a long line of cartographers who’ve helped to make sense of the world and our place in it. But rather than filling in the terra incognita of our planet, he’s plotting the lay of the cosmic land, sketching oceans of empty space and the shorelines of vast superclusters of galaxies.
Tully teased some of his latest findings two years ago at a conference in Marseille, France, held partly in honor of his 70th birthday. Then last September, he and his colleagues published a paper in Nature that unveiled their completed masterwork, a map of a single cosmic structure at least 500 million light-years in diameter. It contains about 100 quadrillion times the mass of the sun, equivalent to 100,000 Milky Ways. If you put the size of the structure in miles, it would be a 3 followed by 21 zeroes. It’s big.
Tully and company propose calling this greatest-known cosmic feature “Laniakea,” from the native Hawaiian words meaning “immeasurable heaven.” The name is evocative yet strangely ironic. Laniakea is measurable, and with this latest discovery, researchers have come closer than ever to defining humanity’s true place within the heavens.
