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. (more…)

[Bonus points to any middle-aged readers who recognize the title^*.]

I still get a thrill every time I see a particularly beautiful image of an astronomical object. But there are some that transcend that beauty, adding a dimension of what-the-what? that makes them just that much cooler.

Like, say, this amazing image of the core of the nearby galaxy M51, taken using Hubble:

[Click to enwhirlpoolenate, or grab the high-res 2 Mb version.]

That is not the swirling drain of despair and fear leading into the mouth of hell. Just to be clear.

What it actually shows is the dust in the inner region of M51, clearly tracing the spiral arms of this magnificent galaxy. The image is false-color, and where it’s brighter there’s more dust (or the dust is being lit up more brightly by nearby stars). You can see the dust is clumpy, too, showing where there are clusters of stars illuminating the dust. Astronomers expected the dust distribution to be somewhat clumpier, but the galaxy had a different idea. It may be smoother due to a close pass by a companion galaxy (well off-screen in this close up shot — we’re seeing the inner 18,000 or so light years here) which disturbed it and prevented dust clouds from getting too big.

How this image was made is interesting, too. Above is a side-by-side shot of the same region. (more…)

One of the closest and most spectacular galaxies in the sky is M51, the Whirlpool. A grand design face-on spiral with a small, irregular companion, it’s so bright and big that it’s a favorite target for amateurs. So you just know when you point Hubble at it, what you get is nothing short of jaw-dropping heart-aching beauty.

Voila:

[Click to galactify.]

This image, using the Hubble Advanced Camera for Surveys, was originally released in 2005, but was recently reprocessed by the phenomenal astrophotographer Robert Gendler. And yeah, you absolutely want to click that link to see the work Robert has done. He’s incredible.

I could go on and on about the galaxy, the glorious spiral arms, the red glow of nebular star birth factories, the odd companion that apparently has drawn out that long tidal tail of stars from the spiral, and so on… but you’ve read that stuff here before.

Instead, while looking this image up, I found the behind-the-scenes story on how they observed it that I think will interest you, my BABloggees. Extra cool is the page showing the galaxy observations in different colors, and you can see just what a big spiral looks like when you use different filters:

You can see the ACS field of view, and the final version on the left. The different observations are listed (each frame is clickable to embiggen on that page, which lets you explore the galaxy on your own). The filters are labeled on the top of each image: B (blue), V (visual, or really yellow), I (near-infrared), and Hα + [NII], the reddish light given off by hot hydrogen clouds laced with nitrogen. That last bit is where stars are being born, and traces the spiral arms very well. The I-band shows very warm dust as well as stars, so it looks smoother since all that stuff is rather smoothly distributed in the galaxy. The B-band has hot stars in it, so again shows where stars are being born; blue stars don’t live very long, and can barely escape their gas cloud nurseries before blowing up as supernovae.

When you put these all together you get the majesty of a spiral galaxy, a city of stars much like our own Milky Way. I’ve seen M51 myself with binoculars and through countless telescopes at star parties, and while it doesn’t look as glorious as it does here — of course — just knowing what’s going on in the galaxy and what it really does look like through the big guns is enough to thrill. It may look blurry and fuzzy through a small telescope, but our brains are big enough to encompass all those light years, and to understand what it is we’re seeing.

Image Credit: NASA, Hubble Heritage Team, (STScI/AURA), ESA, S. Beckwith (STScI). Additional Processing: Robert Gendler