Chandra's Top 10 Scientific Contributions

NASA's Chandra X-ray Observatory is celebrating 10 years of exploring the invisible universe. On Aug. 19, 1999, Chandra captured its first image as an astronomical observatory. This first light image opened a new era for science as Chandra began its mission to open a mysterious universe.

Chandra enables scientists from around the world to obtain unprecedented X-ray images of exotic environments to help understand the evolution of the cosmos. The observatory not only helps to probe these mysteries, but also serves as a unique tool to study detailed physics in a laboratory that cannot be replicated on Earth.

"Chandra has changed the whole understanding of dark matter and increased our knowledge of dark energy, as well as gathered new information on black holes," said Dr. Martin Weisskopf, Chandra project scientist at the Marshall Space Flight Center.

"Chandra has produced 10,000 observations in its 10-year life and the demand for observation time, by scientists, is five- to six-times what is available," said Chandra Program Manager Keith Hefner of the Marshall Center. "It continues to be an engineering marvel that has more than doubled its original five-year mission."

A Chandra "Top 10" reveals some of the most noteworthy discoveries:

1. Chandra finds a ring around the Crab Nebula. After only two months in space, the observatory reveals a brilliant ring around the heart of the Crab Pulsar in the Crab Nebula -- the remains of a stellar explosion -- providing clues about how the nebula is energized by a pulsing neutron, or collapsed star. (Sept. 28, 1999)
2. Chandra finds the most distant X-ray cluster. Using the Chandra Observatory, astronomers find the most distant X-ray cluster of galaxies yet. Approximately 10 billion light years from Earth, the cluster 3C294 is 40 percent farther than the next most distant X-ray galaxy cluster. (Feb. 15, 2001)
3. Chandra makes deepest X-ray exposure. A Chandra image, Deep Field North, captures for 23 days an area of the sky one-fifth the size of the full moon. Even though the faintest sources detected produced only one X-ray photon every four days, Chandra finds more than 600 X-ray sources, most of them super massive black holes in galaxy centers. (June 19, 2003)
4. Chandra hears a black hole. Using the Chandra observatory, astronomers for the first time detected sound waves from a super massive black hole. Coming from a black hole 250 million light years from Earth, the "note" is the deepest ever detected from an object in the universe. (Sept. 9, 2003)
5. Chandra opens a new line of investigation on dark energy. Using galaxy-cluster images from Chandra, astronomers apply a powerful, new method for detecting and probing dark energy. The results offer intriguing clues about the nature of dark energy and the fate of the universe. (May 18, 2004)
6. Chandra finds that Saturn reflects X-rays from the sun. The findings stem from the first observation of an X-ray flare reflected from Saturn's low-latitudes -- the region that correlates to Earth's equator and tropics. (May 25, 2005)
7. Chandra finds proof of dark matter. In galaxy clusters, the normal matter, like the atoms that make up the stars, planets, and everything on Earth, is primarily in the form of hot gas and stars. The mass of the hot gas between the galaxies is far greater than the mass of the stars in all of the galaxies. This normal matter is bound in the cluster by the gravity of an even greater mass of dark matter. Without dark matter, which is invisible and can only be detected through its gravity, the fast-moving galaxies and the hot gas would quickly fly apart. (Aug. 21, 2006)
8. Chandra sees brightest supernova ever. The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes. This discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and that a similar explosion may be ready to go off in our own galaxy. (May 7, 2007)
9. Chandra finds a new way to weigh black holes. By measuring a peak in the temperature of hot gas in the center of the giant elliptical galaxy NGC 4649, scientists have determined the mass of the galaxy's super massive black hole. The method, applied for the first time, gives results that are consistent with a traditional technique. (July 16, 2008)
10. Long observation from Chandra identified the source of this energy for blobs. The X-ray data show that a significant source of power within these colossal structures is from growing super massive black holes partially obscured by dense layers of dust and gas. The fireworks of star formation in galaxies are also seen to play an important role, thanks to Spitzer Space Telescope and ground-based observations. (June 24, 2009)

The Marshall Center manages the Chandra program for the Science and Mission Directorate, NASA Headquarters, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

To see 100 of Chandra's "Greatest Hits" from the past 10 years, check out the slideshow below: