Major Milestones In X-ray Astronomy

Major Milestones In X-ray Astronomyby WKT June 6, 2002 :: In September, 1949, a team led by Herbert Friedman of the Naval Research Laboratory detected weak X-ray emission from the solar corona, the hot outer layers of the Sun's atmosphere. Their experiment consisted of a collection of small Geiger counters aboard a captured German V-2 rocket. It took more than a decade before a greatly improved detector discovered X-rays coming from sources beyond the solar system. In 1962, a team of scientists under the direction of Riccardo Giacconi at American Science and Engineering in Cambridge, MA., used a small X-ray detector aboard an Aerobee rocket to discover Scorpius X-1, the first source of X-rays outside our solar system. Forty years later, over 100,000 X-ray sources have been detected, the most distant of which is 13 billion light years from Earth. This extraordinary leap in sensitivity has been due, in large part, to the development of telescopes that can focus X-rays.
Flash Versionof Timeline The first imaging X-ray telescope was made by Giacconi and collaborators. It was flown on a small sounding rocket in October 1963 and made crude images of hot spots in the upper atmosphere of the sun. This telescope was about the same diameter and length as the optical telescope Galileo used in 1610. Over a period of 380 years, optical telescopes improved in sensitivity by 100 million times from Galileo's telescope to the Hubble Space Telescope. Remarkably, the Chandra X-ray Observatory represents a comparable leap in sensitivity over Giacconi's 1963 telescope, yet it took only 36 years!