Chandra X-Ray Observatory Center

The Chandra X-ray Observatory, previously known as the Advanced X-ray Astrophysics Facility, is a Flagship-class space telescope launched aboard the Space Shuttle Columbia during STS-93 by NASA on July 23, 1999.

Chandra X-Ray Observatory Center

Science Facts Written by Chandra X-Ray Observatory Center


White Dwarfs

White dwarfs are among the dimmest stars in the universe. Even so, they have commanded the attention of astronomers ever since the first white dwarf was observed by optical telescopes in the middle of ... Continue reading

The artist's illustration depicts a classical nova binary system just before an explosion on the surface of the white dwarf. Classical novas occur in a system where a white dwarf closely orbits a normal, companion star.

X-ray Telescopes

X-rays are a highly energetic form of light, not visible to human eyes. Light can take on many forms -- including radio waves, microwaves, infrared, visible, ultraviolet, X-ray and gamma radiation. ... Continue reading

Chandra X-ray Observatory

The Chandra Mission

NASA's Chandra X-ray Observatory, which was launched and deployed by Space Shuttle Columbia on July 23, 1999, is the most sophisticated X-ray observatory built to date. Chandra is designed to observe ... Continue reading


X-ray Emissions From Comets

The X-ray emission from comets is produced by high-energy particles, but the high-energy particles come not from the comet but from the sun. Matter is continually evaporating from the solar corona in ... Continue reading

The white lines represent the solar wind; the purple line is the bow shock produced by the interaction of the solar wind with the Earth's protective magnetosphere (blue lines). (Image not to scale.)

Crab Nebula

For millions of years a star shone in the far off constellation of Taurus. So far away, and so faint that even if our eyes were ten thousand times more sensitive, the star would still not be visible ... Continue reading


Starburst, No, Not The Candy

A starburst galaxy is a galaxy experiencing a period of intense star forming activity. Although this activity may last for ten million years or more, that is like a month in the life of a ten billion ... Continue reading

M82, at a distance of 11 million light years, is a rare nearby starburst galaxy where stars are forming and expiring at a rate ten times higher than in our galaxy.

Neutron Stars

Ordinary matter, or the stuff we and everything around us is made of, consists largely of empty space. Even a rock is mostly empty space. This is because matter is made of atoms. An atom is a cloud of ... Continue reading

Chandra image of the Vela Pulsar.

Subrahmanyan Chandrasekhar

NASA's premier X-ray observatory was named the Chandra X-ray Observatory in honor of the late Indian-American Nobel laureate, Subrahmanyan Chandrasekhar (pronounced: su/bra/mon'/yon chandra/say/kar). ... Continue reading


Groups & Clusters of Galaxies

Galaxy clusters are the largest gravitationally bound objects in the universe. They have three major components: (i) hundreds of galaxies containing stars, gas and dust; (ii) vast clouds of hot (30 - ... Continue reading

Hydra A is a galaxy cluster that is 840 million light years from Earth (redshift = .054). The cluster gets its name from the strong radio source, Hydra A, that originates in a galaxy near the center of the cluster.

Introduction to Constellations

'Constellation' is the name we give to seeming patterns of starsin the night sky. 'Stella' is the Latin word for star and a constellation is a grouping of stars. In general, the stars in these groups ... Continue reading

Constellation Sagittarius.

Galaxy Cluster RDCS 1252.9-2927

A color composite image of the galaxy cluster RDCS 1252.9-2927 shows the X-ray (purple) light from 70-million-degree Celsius gas in the cluster, and the optical (red, yellow and green) light from the ... Continue reading


X-Ray Images & False Color

The colors we see in the world around us are the result of the way that the human eye and brain perceive different wavelengths of light in the visible part of the electromagnetic spectrum. X-rays, and ... Continue reading

Chandra Full-Field of Sagittarius A*. This full-field image of Sagittarius A* is color coded by intensity to show X-rays from 3.3-4.7 keV.

X-Ray Astronomy vs. Medical X-Rays

It's natural to associate the X-rays from cosmic objects with an X-ray from the doctor's office, but the comparison is a bit tricky. A doctor's X-ray machine consists of two parts: an X-ray source at ... Continue reading

Doctor's X-ray machine & X-ray emissions from Cosmic Objects

X-Rays - Another Form of Light

A new form of radiation was discovered in 1895 by Wilhelm Roentgen, a German physicist. He called it X-radiation to denote its unknown nature. This mysterious radiation had the ability to pass through ... Continue reading

X-rays can be produced by a high-speed collision between an electron and a proton.

A Giant X-Ray Machine

The first clear detection of X-rays from the giant, gaseous planet Saturn has been made with NASA's Chandra X-ray Observatory. Chandra's image shows that the X-rays are concentrated near Saturn's ... Continue reading


Powerful Quasars

Quasars appear as distant, highly luminous objects that look like stars. Strong evidence now exists that a quasar is produced by gas falling into a supermassive black hole in the center of a galaxy. ... Continue reading


Dark Matter Mystery

While carefully measuring the speed of rotation of galaxies, astronomers stumbled upon a profound cosmic mystery. Determining the gravity of the galaxy. They could estimate what the rotation speed ... Continue reading

Hot Gas Clouds

Binary and Multiple Star Systems

Stars, like people, are seldom found in isolation. More than 80% of all stars are members of multiple star systems containing two or more stars. Exactly how these systems are formed is not well ... Continue reading

An X-ray image of the Sirius star system located 8.6 light years from Earth.