NASA Studies Gravitational Lensing

    Published: 06-16-2009
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    NASA conducts the first ever gamma-ray study of a gravitational lens using data from its Fermi gamma-ray observatory.

    NASA has conducted the first ever gamma-ray study of a gravitational lens.  This phenomenon is created when a galaxy or other massive object bends and amplifies light heading toward an observer from a more distant source.  Researchers used NASA’s Fermi gamma-ray observatory in low-Earth orbit to collect data by observing gamma ray flares from a source 4.35 billion light years away from Earth. The source known as B0218+357, is an active galaxy known as a blazar, that has a supermassive black hole in the middle, spirals inward and occasionally blasts billions of jet particles traveling close to the speed of light. Before the light reaches the Earth, it travels through a spiral galaxy about 4 billion light years away and bends into different paths. Scientists had to use radio and optical telescopes to monitor these dual images, as Fermi's LAT could not. Through their observations, they found that gamma ray waves lasted one day longer than the one seen for radio observations and that gamma-ray flares and their playback show brightness, unlike the radio waves. The study provided new details on the workings of black hole jets and could help to establish new guides on important cosmological measures in the future.