APOD: 2026 September 30 – Arp 78: Peculiar Galaxy in Aries
APOD Science APOD APOD: 2026 September 30 –… 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. Arp 78: Peculiar […]
On September 30, 2026, the Astronomy Picture of the Day (APOD) featured Arp 78, a peculiar spiral galaxy located in the constellation Aries. This large galaxy, 200,000 light-years across, is situated approximately 100 million light-years away from our Milky Way galaxy. Arp 78, alternatively known as NGC 772, displays an impressive outer spiral arm highlighted by sweeping dust lanes and clusters of young, blue stars.
The galaxy's striking feature, however, lies in its overdeveloped and "pumped-up" spiral arm. This intriguing phenomenon is believed to be the result of gravitational tides generated by galactic-scale interactions with its nearby companion galaxy, NGC 770. NGC 770, a more compact elliptical galaxy seen directly beneath the larger spiral, stands in stark contrast with its fuzzy appearance amidst the faint star streams captured in this deep telescopic exposure.
NGC 770's elliptical shape starkly contrasts with the spiky foreground Milky Way stars, making its presence distinctly visible in the image. The original photograph was captured by Robert Eder, and the accompanying description and credits were provided by Jerry Bonnell, Cecilia Chirenti, Robert Nemiroff, and Keighley Rockcliffe.
Written by urgent.news from NASA's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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- APOD: 2026 September 30 – Arp 78: Peculiar Galaxy in Aries science.nasa.gov
