irregular cluster

astronomy

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June 29, 2026

Quick Summary

The term "irregular cluster" in astronomy can refer to two distinct concepts:

Irregular Galaxies

These are galaxies that lack a defined symmetrical structure or a central nucleus. They often appear as chaotic, grainy assemblages of luminous areas and are typically bluer than spiral galaxies. Some irregular galaxies, like the Large Magellanic Cloud, have a bar structure.1

Irregular Galaxy Clusters

These are large, loosely structured collections of over 1,000 galaxies of mixed types, primarily spirals and ellipticals. They can span 10 to 50 million light-years. The Virgo and Hercules clusters are examples of irregular clusters.2

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Irregular clusters
Irregular clusters are large loosely structured assemblages of mixed galaxy types (mostly spirals and ellipticals), totaling perhaps 1,000 or more systems and extending out 10,000,000 to 50,000,000 light-years. The Virgo and Hercules clusters are representative of this class.
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Irregular clusters are large loosely structured assemblages of mixed galaxy types (mostly spirals and ellipticals), totaling perhaps 1,000 or more systems and extending out 10,000,000 to 50,000,000 light-years. The Virgo and Hercules clusters are representative of this class.
Read More