APOD: 2026 August 4 – Curious Cometary Knots in the Helix Nebula

APOD Science APOD APOD: 2026 August 4 –… Today’s APOD Archive Submissions Index Search Calendar RSS Education About Discuss APOD Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Curious Cometary Knots in the Helix Nebula What causes unusual knots of gas and dust in planetary nebulas ?

Seen also in the Ring Nebula , the Dumbbell Nebula and NGC 2392 , the knots’ existence was not initially predicted, and their origins are still not well understood . Pictured here is a fascinating image of part of the Helix Nebula by the James Webb Space Telescope showing tremendous detail in infrared light . The cometary knots have masses similar to the Earth but have sizes typically several times the orbit of Pluto.

One hypothesis for the fragmentation and evolution of the knots includes existing gas being driven out by a less dense but highly energetic stellar wind of the central evolving star. The Helix Nebula is one of the closest examples of a planetary nebula created at the end of the life of a Sun-like star . Given a technical designation of NGC 7293, the Helix Nebula lies about 650 light-year s away towards the constellation of Water Carrier ( Aquarius ).

Date August 4, 2026 Credit Image: NASA, ESA, CSA, STScI; Image Processing: Alyssa Pagan (STScI) Authors & editors: Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti, Keighley Rockcliffe A service of: ASD at NASA / GSFC , NASA Science Activation & Michigan Tech. U.