ABSTRACT
The sun emits X-rays only from its thin, tenuous outer corona, where temperatures are the highest. X-ray images of the sun have revealed a strong association between areas of the sun that are X-ray bright, and areas that have strong magnetic fields. In 1949, Herbert Friedman first discovered X-rays from the sun by using a sensitive detector similar to a geiger counter bolted on to a German V-2 rocket. In 1961, during another rocket flight, X- rays from another star were detected. Since this was the strongest X-ray source in the direction of the constellation Scorpius, the stellar X-ray source was named Sco X-l. X-rays have enabled to see the universe, in a new light. Astronomers discovered that the entire sky glows dimly in X-rays. Thus, an era of X-ray astronomy began that by has seen several much more sensitive X-ray telescopes launched into space. These in their turn have revealed a wealth of new information about the universe.
