Conceived by R.K. Luneberg at Brown University in 1944, the lens is spherical and symmetrical and, therefore, very effective at multibeaming, or handling many sources simultaneously, much as an eyeball does. "A traditional dish antenna looks in only one direction at a time," says Hall. "But by populating a Luneberg lens' focal surface with feed antennas, we can make a radio 'retina.'"
Hall and his Australian colleagues are testing the lens for use in a huge radio-wave telescope hundreds of times larger than any in operation today. The project, to be built in 2010 by an 11-nation consortium, will be called the Square Kilometre Array. Plans call for tens of thousands of Luneberg lenses to be grouped in arrays at hundreds of different locations. This large collecting area would be able to peer far enough into space to receive "whispers" from the first billion years of the universe's existence.