Watch As a Supernova Morphs and Its Speedy Shock Waves Reverse

A new video from NASA shows how a supernova explosion morphs and changes during a 13-year period, The growing debris field, known as Cassiopeia A or Cas A, likely was generated after a star explosion in 1680. New data from NASA's Chandra X-Ray Observatory shows that even an old explosion can change in subtle ways during a human lifetime.

If you watch the arrows in the video closely, you can see shock waves in blue reverberating through space in data collected between 2000 and 2013. The shock waves are producing X-ray emissions and accelerating particles to high speeds.

The video combines X-ray data from Chandra with observations from the Hubble Space Telescope, which observes in visual and infrared light. Hubble's data was held constant to emphasize the changes Chandra observed over time, according to Chandra personnel.

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"As the blast wave travels outwards at speeds of about 11 million miles [18 million km] per hour, it encounters surrounding material and slows down, generating a second shock wave," Chandra mission personnel said in a statement. This "reverse shock," the agency continued, "travels backwards, similar to how a traffic jam travels backwards from the scene of an accident on a highway."

While reverse shocks typically travel more slowly than the initial blast wave, scientists have realized that some of those in Cas A do the opposite. Their speeds remain fairly high, between about 5 million and 9 million mph (8 million and 14 million km/h). The phenomenon could be the result of the initial blast wave running into a patch of material and slowing down.

A view of Cassiopeia A that includes Chandra X-ray Observatory data. (Image credit: X-ray: NASA/CXC/RIKEN/T. Sato et al.; Optical: NASA/STScI)

Cas A was the first object that Chandra observed, shortly after its launch to space on July 23, 1999. That first observation yielded new science, NASA noted, because Chandra observed a neutron star — the dense remnant left behind from a star explosion — embedded in the debris.

Other observations from Chandra over the decades have shown some of the key elements for life in the explosion and have also generated 3D models of the supernova remnant, NASA said.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: