Ursa Major Cluster
galaxy cluster
The Ursa Major Cluster (Ursa Major I Cluster, UMa I ClG) is a spiral-rich galaxy cluster of the Virgo Supercluster.
Some of its largest members are NGC 3631, NGC 3953, M109 on North (M109 Group) and NGC 3726, NGC 3938, NGC 4051 on South.
The Ursa Major cluster is located at a distance of 18.6 megaparsecs (60 million light-years) and contains about 30% of the light emitted but only 5% of the mass of the nearby Virgo Cluster.
The Ursa Major Cluster is part of the Ursa Major Cloud, a dense filament of about approximately 580 galaxies, that was identified and described in 1987 by astronomer Brent Tully with colleague Richard Fisher in his book The Nearby Galaxies Atlas, as Cloud 12, and contains many other groups of galaxies besides the Ursa Major Cluster. The Ursa Major Cloud is part of a larger filament, emanating from the Centaurus Cluster through the Virgo Cluster and continues through the Ursa Major Cluster all the way to the Perseus–Pisces Supercluster, that is known as the Virgo Strand or Centaurus–Virgo–PP Filament.
“Ursa Major Cluster” enters the record as galaxy cluster. Crown Archives preserves that source wording while asking what Ursa, Major and Cluster can confirm, complicate or overturn.
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“Ursa Major Cluster” is worth following because a concise public description often conceals a longer documentary argument. Here, Ursa, Major and Cluster provides the most credible route into that argument.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Jul 28, 2026. The linked authority identifier is Q338941. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1987.
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This entry incorporates text from “Ursa Major Cluster” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.