NGC 891 looks as the
Milky Way would look like when viewed edge-on (some astronomers have even noted how similar to NGC 891 our galaxy looks as seen from the
Southern Hemisphere) and, in fact, both galaxies are considered very similar in terms of luminosity and size; studies of the dynamics of its molecular
hydrogen have also proven the likely presence of a central
bar. Despite this, recent high-resolution images of its dusty disk show unusual filamentary patterns. These patterns are extending into the
halo of the galaxy, away from its
galactic disk. Scientists presume that supernova explosions caused this interstellar dust to be thrown out of the galactic disk toward the halo. It may also be possible that the light pressure from surrounding stars causes this phenomenon.
Hubble Space Telescope (HST) image of NGC 891. Credit: HST/
NASA/
ESA The galaxy is a member of a small group of galaxies, sometimes called the
NGC 1023 Group. Other galaxies in this group are the NGCs
925,
949,
959,
1003,
1023, and
1058, and the UGCs
1807,
1865 (DDO 19),
2014 (DDO 22),
2023 (DDO 25),
2034 (DDO 24), and
2259. Its outskirts are populated by multiple low-
surface brightness, coherent, and vast substructures, like giant streams that loop around the parent galaxy up to distances of approximately 50 kpc. The bulge and the disk are surrounded by a flat and thick cocoon-like stellar structure. These have vertical and radial distances of up to 15 kpc and 40 kpc, respectively, and are interpreted as the remnant of a
satellite galaxy disrupted and in the process of being absorbed by NGC 891. , 3.24′ view. Credit:
NASA/
STScI/
WikiSky ==In popular culture==