Huge clouds of hot gas shine brightly around the galaxy NGC1399 when it is viewed in the short wavelengths of X-rays, recorded here by the X-ray telescope of the Einstein Observatory. Satellites can take instruments into space to observe the universe in ways which are impossible from the ground. X-rays from space cannot penetrate Earth's atmosphere to reach ground-based telescopes, and astronomers knew little about the exact shape and structure of X-ray emitting astronomical objects until the launch of the Einstein Observatory in November 1978. The gas shown here is at a temperature of 100 million degrees, and is invisible to ordinary light-gathering telescope.