• March 13, 2008

    Episode 150: Natural Telescopes

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    Gravitational lenses are like giant magnifying glasses in the sky. They occur where huge accumulations of matter, like galaxy clusters, create enough gravity to warp and magnify the light of objects beyond them. This enables us to see objects normally too far away to be viewed by even the most powerful telescopes. Gravitational lenses were once thought to be rare. But astronomers using Hubble have found several, and new sky surveys found more. Scientists are now training a "digital robot" to find additional lenses.