Space Antimatter-Powered Supernovae The largest stars die in explosions more powerful than anyone thought possible—some triggered in part by the production of antimatter By Avishay Gal-Yam THIS IS A PREVIEW. Buy this digital issue or subscribe to access the full article. Already a subscriber or purchased this issue? Sign In Illustration by Ron Miller In the middle of 2005 the W. M. Keck observatory on Mauna Kea in Hawaii completed an upgrade of one of its giant twin telescopes. By automatically correcting for atmospheric turbulence, the instrument could now produce images as sharp as those from the Hubble Space Telescope. Shrinivas Kulkarni of the California Institute of Technology urged young Caltech researchers—myself among them—to apply for observing time. Once the rest of the astronomy community realized how terrific the telescopes were, he warned us, securing a slot would become very competitive. Taking this advice, I teamed up with my then fellow postdocs Derek Fox and Doug Leonard to attempt a type of study that previously had been carried out almost solely with the Hubble: hunting for supernova progenitors. In other words, we wanted to know what stars look like when they are about to explode. THIS IS A PREVIEW. Buy this digital issue or subscribe to access the full article. Already a subscriber or purchased this issue? Sign In Buy Digital Issue $7.99 Add To Cart Digital Issue + Subscription $39.99 Subscribe ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2015 Scientific American, a Division of Nature America, Inc. All Rights Reserved.