The Endless Waltz

If there was a time signature for this waltz it would be written in 3,000,000,000/4 or something along those lines.  That’s 3 billion beats per measure and a quarter note is one beat for my musically un-inclined friends.  Ninety million light years away in the pair of galaxies called Arp 271 a long, slow dance has begun between two similar spiral galaxies, NGC 5426 and NGC 5427.  Both are spiral galaxies located in the constellation Virgo.  The two galaxies began interacting likely a several million years ago and the evidence of their intertwining is now readily visible in this beautiful image from the Mt. Lemon Sky Center in Arizona.  The gravity between the interacting galaxies has begun to pull some of the outer stars towards the center creating a bridge of stars.  The bright pink colored gas inside the galaxies are massive molecular clouds which have been energized by the extra gravitation pull and have begun igniting new stars and will cause others to explode in supernovae.

Little is currently known about the fate of these two waltzing galaxies yet.  It all depends on how fast they’re travelling through the cosmos.  At a higher speed they’ll smash right into each other and rip themselves apart.  Once scattered about, gravity will eventually pull the remains back together again.  Or, if they’re not travelling all that fast they’ll kind of do-si-do around each other, until they ultimately merge into one massive new galaxy.  Either way the dance will take millions and millions of years to complete.  The study of colliding galaxies is an intriguing topic because it gives us insight as to what will happen in a couple billion years when our own galaxy will collide with our nearest neighbor, the Andromeda galaxy.

Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona