[Over the past few weeks, I've collected a metric ton of cool pictures to post, but somehow have never gotten around to actually posting them. Sometimes I was too busy, sometimes too lazy, sometimes they just fell by the wayside... but I decided my computer's desktop was getting cluttered, and I'll never clean it up without some sort of incentive. I've therefore made a pact with myself to post one of the pictures with an abbreviated description every day until they're gone, thus cleaning up my desktop, showing you neat and/or beautiful pictures, and making me feel better about my work habits. Enjoy.]
IC 342 is a relatively close by face-on spiral galaxy. At 10 million light years distant, it should actually be easily visible in binoculars and would be renowned for its incredible beauty except for one small problem: we have to peer through the thick dust choking our own galaxy to see it. It’s like sitting in a smoky room and trying to see something out the window on the far side of it. Your view is obscured.
But infrared light passes through dust quite easily, so when you turn an IR telescope — like NASA’s Spitzer Space Telescope — toward IC 342, what you get is spidery magic!
[Click to embiggen.]
Holy wow! What you’re seeing is the dust in IC 342 glowing where stars are being born; giant gas clouds are star birth factories, and are shrouded in dust. The stars’ light warms the dust up and it glows. The vast complex of nebulae trace out the spiral arms, looking like a web knit by an astronomically-minded spider.
I’ve written about IC 342 twice before. Once was when the NOAO released a gorgeous image of it taken by my friend Travis Rector. Seriously, click that link. The image is spectacular.
The other time was last year when WISE, another infrared observatory, took a look at IC 342. The view is pretty similar, as you might expect — the parts of the infrared spectrum making up both images are nearly the same — but Spitzer’s mirror is twice the size of the one in WISE, so the resolution is somewhat better.
Still, the more the merrier! IC 342 is a dramatic example of a nearby face-on spiral, and there aren’t too many of those around. Even though our own Milky Way galaxy has photobombed it into relative obscurity, the prying eyes of science are pretty good at seeing through all that.
The Wide-field Infrared Survey Explorer was turned off a few months ago, but the science it did lives on. NASA just released a gallery of nine spiral galaxy images taken by WISE, and they’re lovely:
[Click to galactinate.]
Several of my favorite big, grand design spirals are there, like M51, M81, and M83. Note that since WISE only sees infrared light, these are false color images; the colors used are blue for 3.4 micron IR light, cyan for 4.6 microns, green for 12 microns, and red for 22 microns. The reddest light a human eye can see is very roughly 0.75 microns, to give you a comparison. In the images, star-forming regions are yellowish and/or pink, dust (in the form of long-chain organic molecules called polycyclic aromatic hydrocarbons) is green, and old stars are blue.
While looking over the images, I actually recognized the name of the one in the lower right: IC 342 (here’s a full-res WISE shot of it). This is part of a small group of galaxies near our Milky Way that is heavily obscured by dust in our galaxy. Read More