{"date":"2026-09-30","post_id":1424625,"title":"Arp 78: Peculiar Galaxy in Aries","permalink":"https://science.nasa.gov/image-article/apod-2026-september-30-arp-78-peculiar-galaxy-in-aries/","media_type":"image","explanation":"Explanation: Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries. Some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy, the island universe is an enormous 200,000 light-years across. Also known as NGC 772, it sports a prominent, outer spiral arm in this detailed cosmic portrait. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78's overdeveloped spiral arm is pumped-up by galactic-scale gravitational tides. Interactions with its brightest companion galaxy, the more compact NGC 770 seen directly below the larger spiral, are likely responsible. Embedded in faint star streams revealed in the deep telescopic exposure, NGC 770's fuzzy, elliptical appearance contrasts nicely with spiky foreground Milky Way stars.

APOD's email for image submissions has changed. Please see: APOD Submissions.
Tomorrow's picture: a harvest","credit":"Robert Eder","copyright":"Robert Eder","alt":"A spiral galaxy viewed face-on with an extended spiral arm.","url":"https://science.nasa.gov/image-article/apod-2026-september-30-arp-78-peculiar-galaxy-in-aries/","hdurl":"https://assets.science.nasa.gov/dynamicimage/assets/science/cds/apod/apod/2026/october/NGC772_Robert_Eder.jpg?w=1772&h=1182&fit=clip&crop=faces%2Cfocalpoint","basic_html":"\n\n\n\n\n APOD: 2026 September 30 - Arp 78: Peculiar Galaxy in Aries\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
\n

Astronomy Picture of the Day

\n

\n\nDiscover the cosmos!\nEach day a different image or photograph of our fascinating universe is\nfeatured, along with a brief explanation written by a professional astronomer.\n

\n\n2026 September 30
\n\n\n\"A\n

\n\n
\n Arp 78: Peculiar Galaxy in Aries
\n\nImage Credit &\nCopyright:\n\nRobert Eder\n
\n\n

\n\n Explanation: \n\nExplanation: Peculiar spiral galaxy Arp 78 is found within the boundaries of the head strong constellation Aries. Some 100 million light-years beyond the stars and nebulae of our Milky Way galaxy, the island universe is an enormous 200,000 light-years across. Also known as NGC 772, it sports a prominent, outer spiral arm in this detailed cosmic portrait. Tracking along sweeping dust lanes and lined with young blue star clusters, Arp 78's overdeveloped spiral arm is pumped-up by galactic-scale gravitational tides. Interactions with its brightest companion galaxy, the more compact NGC 770 seen directly below the larger spiral, are likely responsible. Embedded in faint star streams revealed in the deep telescopic exposure, NGC 770's fuzzy, elliptical appearance contrasts nicely with spiky foreground Milky Way stars.

APOD's email for image submissions has changed. Please see: APOD Submissions.
Tomorrow's picture: a harvest\n

\n\n Tomorrow's picture: APOD: 2026 October 1 – Harvest Moon with Erupting Mount Etna\n\n

\n<\n| Archive\n| Index\n| Search\n| Calendar\n| RSS\n| Education\n| About APOD\n| >\n\n

\n Authors & editors: \nJerry Bonnell, Cecilia Chirenti, Robert Nemiroff, Keighley Rockcliffe
\nNASA Official: Dana BollesSpecific rights apply.
\nNASA Web\nPrivacy Policy and Important Notices
\nA service of:\nASD at\nNASA /\nGSFC\n
& Michigan Tech. U.
\n

\n\n","basic_html_url":"https://science.nasa.gov/wp-json/wp/v2/apod-basic/260930/html"}