Scientists have concluded the checkout period for NASA's Hubble Space Telescope and now are revealing images showcasing the power of the much-improved observatory. This zoom into galaxy cluster Abell 370 brings us to a Hubble image that features a prominent arc near the right-hand side of the picture. This is the gravitational lens effect from a background galaxy. Astronomers believe this distortion is caused by dark matter that holds together as many as 1,000 galaxies and intergalactic hot gas.
Publication: September 9, 2009