An image of the microwave background radiation made by the CAT.

This is the first detailed image of the microwave background radiation, made by the CAT. Each "blob" is about the same size on the sky as the full moon, and represent a patch of sky which is about 0.0001 degrees hotter (white) or cooler (black) than average. These hot and cold blobs, seen here as they were only 100,000 years after the big bang, will by now have grown into large super-clusters of galaxies. The COBE satellite, which first mapped the features in the background radiation over the whole sky, would see this whole region as a single feature, with none of the fine detail.

The CAT observation is of a small patch of sky near the constellation Ursa Major (the Plough).

A colour Postscript version of this image is available (575kb), as is a gzip compressed version (75kb). (If your browser is configured to view .ps files automatically, you may want to shift/click on the Postscript link to download the file.)

More detailed information about the image.