Hubble spots gigantic elliptical galaxy, 100 million light-years from Earth

NASA today released a new picture of NGC 474, a gigantic elliptical galaxy that lies some 100 million light-years away from Earth. Captured by the NASA/ESA Hubble Space Telescope, the image shows the central region of the galaxy, which spans about 250,000 light-years across – that's 2.5 times larger than our home galaxy Milky Way.

The image uses data from Hubble's Advanced Camera for Surveys (ACS). The telescope's Wide Field and Planetary Camera 2 and Wide Field Camera 3 provided additional gap-filling data.

In this Hubble image of NGC 474, the blue color represents visible blue light while orange represents near-infrared light.

NGC 474 hosts a series of complex layered shells, the cause of which is currently unknown. Astronomers theorize that the spectacular tidal shells may be the after-effects of the giant galaxy absorbing one or more smaller galaxies. Just like a pebble creates ripples on a pond when dropped into the water, the absorbed galaxy creates waves that form the shells.

According to NASA, about 10% of elliptical galaxies have shell structures, but unlike the majority of elliptical galaxies, which are associated with galaxy clusters, shelled ellipticals usually lie in relatively empty space. It may be that they've cannibalized their neighbours.