Inexpensive interferometer maps cosmic microwaves

17 Jun 2002

Using a relatively cheap prototype ground-based telescope, a British team has created an image of the cosmic microwave background--the faint echo of the big bang--that is many times sharper than those obtained from balloons and satellites. The secret of the instrument's sharp vision is interferometry: combining the signals from separate antennas into a single image. While the image is largely a proof of principle, it is tantalizing astronomers by showing hot spots--peaks in the density of the primordial universe--that may mark the origins of present-day galaxy clusters.