The Milky Way is a barred spiral galaxy

We all grew up being told that the Milky Way was a spiral galaxy, twisting beautiful starry arms through inky space like our photogenic neighbor Andromeda. So it may have come as a surprise to you, as it did to me, to learn that in 2005 the Spitzer Space Telescope confirmed that in fact we live in a barred spiral galaxy instead. This isn’t that strange; apparently up to two-thirds of all spiral galaxies contain a bar.

Even more interesting, our galaxy has four arms (in our current understanding of its structure) and they have each been named. We reside in the Orion arm, a small offshoot between the Carina-Sagittarius and Perseus arms. The main two other arms are Scutum-Crux and Norma.

As a side note, the wikipedia page on barred spiral galaxies includes this rather unfortunate statement:

“Studying the core of the Milky Way, scientists found out that the Milky Way’s bulge was peanut-shaped. This led to the conclusion that all barred spiral galaxies have a peanut shaped bulge.”

I’m guessing that more was involved than simply generalizing from a single example.

Also fun is this list of Ten Things You Don’t Know about the Milky Way Galaxy. I was pleased to discover that I knew all but #8 and #9 — and also pleased that there were two new things to learn.