A new golden era of space exploration and discovery began April 24, 1990 with the launch and deployment of the Hubble telescope. Over the past six years Hubble's rapid-fire rate of unprecedented discoveries has invigorated astronomy. Not since the invention of the telescope nearly 400 years ago have astronomers' vision of the universe been so revolutionized over such a short stretch of time.
This picture, released to commemorate Hubble's sixth anniversary, shows several blue, loop-shaped objects that are actually multiple images of the same galaxy. The duplicate images were produced by a cosmic lens in space: the massive cluster of yellow elliptical and spiral galaxies near the photograph's center. This cosmic lens, called a gravitational lens, is created by the cluster's tremendous gravitational field, which bends light from a distant object and magnifies, brightens, and distorts it. How distorted the image becomes and how many copies are made depends on the alignment between the foreground cluster and the more distant galaxy.