NASA: Hubble Sees Spiral in Andromeda

The Andromeda constellation is one of the 88 modern constellations and should not be confused with our neighboring Andromeda Galaxy.  The Andromeda constellation is home to the pictured galaxy known as NGC 7640.

Many different classifications are used to identify galaxies by shape and structure — NGC 7640 is a barred spiral type.  These are recognizable by their spiral arms, which fan out not from a circular core, but from an elongated bar cutting through the galaxy’s center. Our home galaxy, the Milky Way, is also a barred spiral galaxy.  NGC 7640 might not look much like a spiral in this image, but this is due to the orientation of the galaxy with respect to Earth — or to Hubble, which acted as photographer in this case!  We often do not see galaxies face on, which can make features such as spiral arms less obvious.

There is evidence that NGC 7640 has experienced some kind of interaction in its past. Galaxies contain vast amounts of mass, and therefore affect one another via gravity.  Sometimes these interactions can be mild, and sometimes hugely dramatic, with two or more colliding and merging into a new, bigger galaxy.  Understanding the history of a galaxy, and what interactions it has experienced, helps astronomers to improve their understanding of how galaxies — and the stars within them — form.

Image credit: ESA/Hubble & NASA

Text credit: European Space Agency

- NASA:  Hubble Sees Spiral in Andromeda


The stunning gorgeosity is obvious but it's a bit carny to use a diffraction grate for the image.  That or something similar is why the stars have little lines shooting out of them.  Usually photographers only pull a diffraction grate from the kit bag for weddings and even then it's reluctant.

There's no need to editorialize anything and I'll go back to "Roots" with this one.

Behold the only thing greater than yourself

- Kunta Kinte