Image Credit: BlackBird II Observatory

Meet NGC 891: a picturesque galaxy found about 30 million light-years from Earth in the Andromeda constellation. Even from this edge-on point of view, we can clearly tell that it's spiral in nature. In fact, it would probably resemble our galaxy (minus a central bar, which may or may not be present in this galaxy) if we were looking at it from a much more distant vantage point. Both are also roughly the same size (about 100,000 light-years across).

That aside,NGC 891 is quite remarkable. It has a large central bulge and a thin galactic disk, with interstellar dust so prevalent, a number of star forming regions have been rendered invisible at optical wavelengths (it also significantly diminishes the galaxy's overall brightness). We can, however, still see the pinkish light emanating from H II regions: places where ultraviolet radiation from young stars has excited the gas surrounding them, causing it to glow brilliantly.

A closer look (Credit: Adam Block, Mt. Lemmon SkyCenter, U. Arizona)

In addition to the lanes of dust in the galaxy's central region, NGC 891 has long lines of it that span hundreds of light-years above and below; astronomers believe this material was ejected from the disk toward the halo by a combination of star formation activity and supernovae explosions.

(See a larger image here.)


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