X-ray astronomy celebrates anniversary

Cosmic X-ray astronomy turned 50 years old this month, NASA said, highlighting the 1962 pioneer effort of a small team of scientists in the New Mexico desert. On June 18, 1962, an X-ray detector, crude by modern standards, was launched from the hot desert sands atop an Aerobee 150 rocket of modest performance, escaping Earth's atmosphere for just 5 minutes 50 seconds and reaching an altitude of 140 miles. Researchers eagerly reviewing the data from the pioneering instrument found just one discrete X-ray source, which they named Scorpius X-1, and a broad, diffuse X-ray glow that would come to be known as the cosmic X-ray background, NASA said in a release this week. While astronomers had previously detected X-rays from the sun, this was the first detection of X-rays outside our Solar System, and X-ray astronomy was born. That crude detector was followed by the first X-ray imaging telescope, sent into space in 1963, in size and shape no bigger than the first optical telescope built by Galileo in 1610. It took four centuries for optical telescopes to improve their sensitivity by the same 100 million times factor that X-ray telescopes have managed in just 40 years, leading to the field's current flagship, NASA's Chandra X-ray Observatory.