Skip to main content

Hubble telescope spots a complex cloud of gas expanding into space

The planetary nebula NGC 6891 glows in this Hubble Space Telescope image. (Image credit: NASA, ESA, A. Hajian (University of Waterloo), H. Bond (Pennsylvania State University), and B. Balick (University of Washington); Processing: Gladys Kober (NASA/Catholic University of America))

This serene cloud of gas belies a lot of activity deep within the nebula.

NGC 6891 glows brightly in a new image from the Hubble Space Telescope, as the observatory assists scientists in learning more about how these gas clouds formed and evolved.

Astronomers call NGC 6891 a "planetary nebula," a term arising from an old misidentification with planets back when telescope technology was in its infancy. Today we know that such nebulas form after smaller stars shed their gas, late in their lifetime. 

Related: The best Hubble Space Telescope images of all time!

The Hubble Space Telescope's high-definition imagery revealed knots and filaments wrapped around the white dwarf embedded deep within the cloud. The data also shows that the outer halo of gas is expanding faster than the innermost part of the nebula, and the observations even catch shells of gas that are oriented in different directions.

"From their motions, astronomers estimate that one of the shells is 4,800 years old while the outer halo is some 28,000 years old, indicating a series of outbursts from the dying star at different times," NASA officials wrote in a statement (opens in new tab).

The glowing from NGC 6891 occurs as the white dwarf stars ionizes, or strips away electrons, from the surrounding hydrogen gas. 

"As the energized electrons revert from their higher-energy state to a lower-energy state by recombining with the hydrogen nuclei, they emit energy in the form of light, causing the nebula’s gas to glow," NASA said.

Hubble is currently in recovery from a synchronization glitch that occured on Oct. 23 and its instruments are slowly being brought back online. Hubble was last serviced in person in 2009 and with the retirement of the space shuttle, is no longer accessible to astronauts. That said, the 31-year-old telescope has plenty of archival data to process.

Correction: This article was corrected to give the correct definition for a planetary nebula.

Follow Elizabeth Howell on Twitter @howellspace (opens in new tab). Follow us on Twitter @Spacedotcom or on Facebook

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell, Ph.D., is a staff writer in the spaceflight channel since 2022. She was contributing writer for Space.com (opens in new tab) for 10 years before that, since 2012. As a proud Trekkie and Canadian, she also tackles topics like diversity, science fiction, astronomy and gaming to help others explore the universe. Elizabeth's on-site reporting includes two human spaceflight launches from Kazakhstan, three space shuttle missions in Florida, and embedded reporting from a simulated Mars mission in Utah. She holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, and a Bachelor of Journalism from Canada's Carleton University. Elizabeth is also a post-secondary instructor in communications and science since 2015. Her latest book, Leadership Moments from NASA, is co-written with astronaut Dave Williams. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday.