Galaxy Groups and Clusters

Most galaxies exist in groups. Some groups are small, like our own Local Group, with three large galaxies and around two dozen tiny ones. Other groups are huge like the Virgo Cluster with 1300 confirmed members. Galaxies are farther organized into superclusters with vast stretches of empty space in between. The reason for this organization is not understood.

Back Up to Deep Space	Stephan's Quintet Regular Size Large Size Full Size Caption Credit: NASA/ESA/Hubble SM4 ERO Team	Perseus Cluster Regular Size Large Size Full Size Caption Credit: Cxielo Astrophotos
Two Spirals and a Dwarf Regular Size Full Size Caption Credit: NASA/ESA/M. Livio (STScI)/Hubble Heritage Team (STScI/AURA)	Markarian's Chain Regular Size Full Size Caption Credit: Lynn van Rooijen	Gravitational Lensing Regular Size Full Size Caption Credit: Andrew Fruchter (STScI) et al./WFPC2/HST/NASA
Ten Thousand Galaxies Regular Size Large Size Full Size Caption Credit: NASA/ESA/S. Beckwith (STScI)/HUDF Team

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