Since its launch on July 23, 1999, the Chandra X-ray Observatory has been NASA’s flagship mission for X-ray astronomy. Specially designed to detect X-ray emissions from extremely hot regions of the universe, it has captured spectacular pictures of several cosmic objects. This catalogue includes supernovae and their remnants, galaxy clusters, planetary nebulas, and matter surrounding black holes. High-energy events such as these can be seen in much greater detail with an X-ray telescope. The data obtained from this range of the spectrum can add an extra dimension to objects in space that also give off visible light. This was the third in NASA’s series of “Great Observatories” designed to explore the universe while sending back detailed information about space from orbit.
The data collected by the CXO has greatly advanced our understanding of X-ray astronomy. These discoveries include:
- X-ray emission from the black hole at the centre of the Milky Way (Saggitarius A*);
- A new type of black hole;
- Cool gas in the centre of the Andromeda galaxy;
- X-ray emissions from main-sequence stars.
The largest cosmic objects that Chandra can image are the X-rays in galaxy clusters so vast that it takes light 5 million years to go from one side to the other! The Observatory uses a high-resolution camera, and a CCD imaging spectrometer to record X-rays from cosmic sources. This selection represents different types of objects ranging from relatively nearby exploded stars to extremely distant and massive clusters of galaxies that emit X-rays detected by Chandra.
E0102-72.3: A One of a Kind Neutron Star Seen for the First Time

(Image released May 23, 2018)
This takes us to the supernova remnants of a star in the Small Magellanic Cloud, nearly 200,000 light-years away from Earth. A new type of neutron star, a rare variety with both a low magnetic field and no stellar companion was this amazing new discovery. X-rays from Chandra (blue and purple) have helped astronomers confirm that most of the oxygen in the universe is synthesized in massive stars. The amount of oxygen in the E0102-72.3 ring shown here is enough for thousands of solar systems.
Abell 1775: A “Slingshot” from Two Titans
Galaxy clusters are known to be the titans of the Universe. The latest study using NASA’s CXO examines the repercussions after the clash of two such titans. By examing the galaxy cluster Abell 1775, a spiral-shaped pattern found in Chandra’s X-ray data indicated a turbulent past for the cluster. Collisions between two galaxy clusters of different sizes cause the smaller cluster to plough through the larger. Frictional forces strip the hot gas and leaves behind a “tail”. As the smaller cluster passes the centre of the larger, gas in the tail overshoots the centre as it encounters lesser resistive forces.
This is termed to be a “slingshot” as the tail curves, extending away from the cluster’s centre. The tail is labelled in this image along with a region of gas with a curved edge, called a “cold front,” that is denser and cooler than the gas it is ploughing into. The tail and the cold front all curve in the same direction, creating a spiral appearance.

Inside the Flame Nebula

Stars are often born in clusters, in giant clouds of gas and dust. Astronomers have studied two star clusters using NASA’s CXO and infrared telescopes. This composite image shows one of the clusters, NGC 2024, which is found in the centre of the so-called Flame Nebula about 1,400 light-years from Earth.
Peering into the Orion Nebula
At a distance of about 1,500 light-years, the Orion Nebula is one of the closest star formation regions to Earth. This makes Orion a favourite for amateur astronomers and casual skywatchers. It also makes an excellent location to study how stars are born and behave during their stellar childhoods. In this composite image, the bright point-like sources (blue and orange) are the newly formed stars captured in X-ray light by a long series of Chandra observations.

Abell 2744: Pandora’s Cluster Revealed
One of the most complicated and dramatic collisions between galaxy clusters ever seen is captured here. This collision site, known officially as Abell 2744, has been dubbed “Pandora’s Cluster” because of the wide variety of different structures seen. This composite image contains the aftermath of a giant collision involving four separate galaxy clusters at a distance of about 3.5 billion light-years.

Supernova 1987A: A Young Supernova Blast Wave
The Chandra X-ray image of SN 1987A made in January 2000 shows an expanding shell of hot gas produced by the supernova explosion. This observation and an earlier Chandra observation in October 1999 are the earliest X-ray images ever made of a shock wave following a supernova event. The colours represent different intensities of X-ray emission, with white being the brightest.

SN 1987A is in the Large Magellanic Cloud, a nearby galaxy that is 160,000 light-years from Earth. Although SN 1987A was a spectacularly violent event, we are watching it from a very safe distance. For a supernova to do real damage to us, it would have to occur at a distance of less than about a hundred light-years, more than a thousand times closer than SN1987A.
Tycho’s Supernova Remnant: Exploding Stars and Stripes

This image comes from a very deep Chandra observation of the Tycho supernova remnant, produced by the explosion of a white dwarf star in our Galaxy. The images and data analysis shows evidence of a pattern of X-ray “stripes”, a very new discovery about supernovae. These are thought to be the result of electrons being trapped in regions where magnetic field lines are more tangled and the subsequent spiralling of these electrons around them. It has been postulated that further analysis of these “stripes” can show an explanation as to how cosmic waves are formed, as well as explaining the amplification of magnetic fields in cosmic blast waves.
X-ray Universe to be Discovered!
Chandra, which uses X-ray radiation to study the universe allows scientists from around the world to obtain X-ray images of exotic environments to help understand the structure and evolution of the universe. Initially, NASA planned the lifetime of the CXO to 5 years. However, NASA extended its lifetime due to the telescope’s outstanding results, and as its mission continues, Chandra will continue to make startling new discoveries about our high-energy Universe.
For more Chandra images, multimedia and related materials, visit NASA’s Chandra X-ray Observatory or the photo album https://chandra.si.edu/photo/.
References
- 01. https://www.schoolsobservatory.org/learn/eng/tels/spacetel/chandra
- 02. https://chandra.harvard.edu/about/fun/index.html
- 03. https://chandra.harvard.edu/resources/podcasts/ts/ts171218_hd.html
- 04. https://www.nasa.gov/mission_pages/chandra/news/astronomers-spot-distant-and-lonely-neutron-star.html
- 05. https://www.nasa.gov/mission_pages/chandra/news/chandra-serves-up-cosmic-holiday-assortment.html
- 06. https://www.nasa.gov/mission_pages/chandra/images/supernova-remnant-e0102-723.html
- 07. https://chandra.harvard.edu/photo/2021/a1775/index.html
- 08. https://www.firstpost.com/tech/science/stunning-images-from-nasas-chandra-x-ray-observatory-show-cosmic-objects-stars-supernovas-8797521.html
- 09. https://www.nasa.gov/mission_pages/chandra/multimedia/tychophoto.html
- 10. https://chandra.harvard.edu/photo/2000/sn1987a/
- 11. https://www.nasa.gov/mission_pages/chandra/news/chandra-catches-slingshot-during-collision.html
- 12. https://www.space.com/17075-pictures-chandra-x-ray-observatory-space-telescope.html
Image Courtesies
- 01. Featured Image: https://bit.ly/3ryRpqm
- 02. Image 01: https://go.nasa.gov/3y5y9Ds
- 03. Image 02: https://bit.ly/3eWSDqp
- 04. Image 03: https://bit.ly/3734mzg
- 05. Image 04: https://bit.ly/371oMbW
- 06. Image 05: https://go.nasa.gov/3kVxmBa
- 07. Image 06: https://bit.ly/3iMTT0r
- 08. Image 07: https://bit.ly/3eSakYk