A stellar discovery on the Milky Way’s far side
Five remarkable stars on the other side of our galaxy promise new insight into the outer reaches of our home turf.
A single Hubble Space Telescope image can capture scores of distant galaxies, but the one galaxy we’ll never see from the outside is our own. As a result, no one knows the Milky Way’s exact size and shape. It took more than a century after the discovery of the first spiral in space before astronomers established that our galaxy is a spiral, too, and more years elapsed before they deduced that we inhabit a barred spiral — a type whose bright central region is elongated. Now, for the first time, observers have detected five stars on the far side of the galaxy that serve as outstanding yardsticks, a feat which will divulge secrets about the Milky Way’s terra incognita. “It’s a beautiful piece of classic astronomy,” says Leo Blitz, an astronomer at the University of California, Berkeley, who was not involved in the discovery.