NASA Astronomy Picture of the Day Collection

The Hercules Cluster of Galaxies

These are galaxies of the Hercules Cluster [ http://www.astr.ua.…], an archipelago of island universes [ http://antwrp.gsfc.…] a mere 500 million light-years away [ http://www.faqs.org…section-14.html ]. Also known as Abell 2151, this cluster [ http://www.atlasoft…] is loaded with gas and dust rich, star-forming spiral [ http://antwrp.gsfc.…] galaxies but has relatively few elliptical [ http://antwrp.gsfc.…] galaxies, which lack gas and dust and the associated newborn stars. The colors in this remarkably deep composite [ http://www.astropho…] image clearly show the star forming galaxies with a blue tint and galaxies with older stellar populations with a yellowish cast. The sharp picture spans about 1/2 degree across the cluster center, corresponding to over 4 million light-years at the cluster's estimated distance. In the cosmic vista many galaxies seem to be colliding [ http://antwrp.gsfc.…] or merging [ http://www.astr.ua.…] while others seem distorted [ http://antwrp.gsfc.…] - clear evidence that cluster galaxies [ http://www.seds.org…] commonly interact. In fact, the Hercules Cluster itself may be seen as the result of ongoing mergers of smaller galaxy clusters and is thought to be similar to young [ http://antwrp.gsfc.…] galaxy clusters in the much more distant, early Universe [ http://antwrp.gsfc.…].

Tony Hallas [ http://astrophoto.c…]

Goddard Space Flight Center (GSFC)

Hercules

http://antwrp.gsfc.…

SPD-APOD-ap070719