Space See Inside Astronomers Use Gravitational Lenses to Push Hubble Past Its Limits To learn how the universe evolved over time, a space telescope gazes back to the earliest galaxies ever observed By Lee Billings NASA, ESA AND J. LOTZ, M. MOUNTAIN, A. KOEKEMOER, AND THE HFF TEAM STScI In this hubble space telescope image, the galaxies of the giant cluster Abell 2744 appear strewn through space like jewels on black velvet. Their light began its journey to Earth some 3.5 billion years ago, when our biosphere was in its infancy. Despite appearances, the galaxies constitute less than 5 percent of the cluster's total mass, most of which resides in halos of invisible dark matter. There is, in fact, so much mass within this cluster that it behaves as a gravitational lens, warping space to magnify light from even deeper cosmic realms. The thousands of azure arcs and dots that surround the bright galaxies are actually distorted images of much fainter background galaxies, which were Hubble's true quarry in this image. We see them as they were more than 12 billion years ago, shortly after the big bang. They are some of the earliest galaxies ever glimpsed and offer a new window into galactic evolution, as well as a preview of what NASA's James Webb Space Telescope will routinely see after it launches later this decade. This is only a preview. Get the rest of this article now! Select an option below: Buy Digital Issue Customer Sign In *You must have purchased this issue or have a qualifying subscription to access this content It has been identified that the institution you are trying to access this article from has institutional site license access to Scientific American on nature.com. Click here to access this article in its entirety through site license access. ADVERTISEMENT Scientific American is a trademark of Scientific American, Inc., used with permission © 2013 Scientific American, a Division of Nature America, Inc. All Rights Reserved.