Monthly Archives: June 2013

astronomy, astronomy news, galaxies, galaxy interactions, galaxy shapes

Galaxy in the Shape of a Hummingbird

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Could the Cosmos Get Any More Fascinating???

A long time ago, back when I was in graduate school, I used to collect those “newspapers” you see at the checkout counters in stores. You know the ones I mean—the ones with screaming headlines about alien babies and mutant animals and UFOs. Since I worked on a Hubble Space Telescope instrument team, I was particularly interested in seeing headlines about it. There were two stories that really made me laugh. The first was headlined “Astronomers Discover Galaxy in Shape of Fetus!!!!!!” and the other was “Hubble Space Telescope Takes Image of Heaven!!!!!”

This interacting galaxy duo is collectively called Arp 142. The pair contains the disturbed, star-forming spiral galaxy NGC 2936, along with its elliptical companion, NGC 2937 at lower left. Courtesy NASA/ESA Hubble Space Telescope/Hubble Heritage Team (STScI/AURA).

Of course, the image of heaven was an HST image of the Orion Nebula, which is a research heaven for people who are studying starbirth regions. But, there was no galaxy fetus out there. The editors of that story had found a press release about how astronomers had detected a faint rhythmic radio signal from a region in a distant galaxy, probably from a supernova or something. Somehow that got transmogrified into a baby galaxy headlined on a pulp rag.

There ARE lots of interestingly shaped galaxies out there, and this week Hubble Space Telescope astronomers released an image of and story about a distant galaxy that looks similar to a hovering hummingbird, sitting close to another elliptical galaxy. It’s called Arp 142, and it’s a snapshot of galaxies interacting. The whole dance of these two galaxies takes millions and millions of years, so we only get to see freeze-frame images like this one.

So, what’s going on here?  Let’s deconstruct the scene.  The “hummingbird” shape galaxy was a spiral galaxy before it began interacting with the elliptical just below it. The gravitational pull between the two galaxies warps the spiral and that affects the orbits of its stars and nebulae. Essentially, it warps the spiral, resulting in the shape you see here.  You can also see interstellar gas being pulled out of the spiral almost like a giant string of taffy.

The whole process compresses the gas and dust in the galaxy, which triggers star formation. You can see blobs of blue throughout the galaxy—those are starburst knots caused as the gravitational dance continues on.  The reddish dust  lanes used to be inside the galaxy. Now they’re being thrown out and compressed into the dark veins you see silhouetted against the bright starlight.

The companion elliptical, NGC 2937, is a puffball of stars with little gas or dust present. The stars contained within the galaxy are mostly old, as evidenced by their reddish color. There are no blue stars that would be evidence of recent star formation. While the orbits of this elliptical’s stars may be altered by the encounter, it’s not apparent that the gravitational pull by its neighboring galaxy is having much of an effect.

Above the pair, an unrelated, lone, bluish galaxy, inconsistently cataloged as UGC 5130, appears to be an elongated irregular or an edge-on spiral. Located 230 million light-years away, this galaxy is much closer to us than the colliding pair, and therefore is not interacting with them. It happens to lie along the same line of sight to foreground Milky Way stars caught in the image.

Now, I find this to be a MUCH more satisfying story than the kinds of things you read in the supermarket rags. Nothing their editors can dream up is anywhere NEAR as fascinating as what the actual cosmos is revealing to us through the watchful eye of the Hubble Space Telescope!

 

astronomy, Astronomy outreach, astronomy-related products, communicating astronomy

Take a Crash Course in Astronomy

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My New Book is Out!

Did you ever take an astronomy course in school? The most commonly taken classes in college are usually called something like “Astronomy 101” and they’re designed to teach the rudiments of this amazing science. The courses give students an idea of the “jargon” of astronomy, the principles of things like planetary orbits, a general look at how stars work, the evolution of galaxies, and so forth. The finer details—that is, the astrophysics and cosmic chemistry of how stars work, etc. —are typically studied in higher-level courses that require more background in physics, and are usually taken by astronomy majors. But, if all you want to know is the general story of how things in the cosmos work, then Astronomy 101 is the perfect class to take. I helped teach some of these courses when I worked at the university during grad school, usually in the planetarium (a perfect place to do it!).

Astronomy 101 on my bookshelf. Put on on yours, too! Image by Carolyn Collins Petersen.
Astronomy 101 on my bookshelf. Put on on yours, too! Image copyright 2013 Carolyn Collins Petersen.

You don’t actually have to take a class to learn about astronomy. There are many fine places online to learn it, or you can buy a book and study at your leisure. As it just so happens, I’ve just written a book called—wait for it— Astronomy 101. It’s available at fine bookstores (both online and in bricks-and-mortar establishments) everywhere. I noted today that my most favorite independent book store, Denver’s Tattered Cover (yes, they ship anywhere!) has it on the shelves. Powell’s also has it, for those of you who patronize that fine store). Astronomy 101 is also on Amazon.  The publisher is Adams Media, and I’m sure they’re working to get it in as many bookstores as possible.

If you’re teaching Astronomy 101 (or similar beginning course), this could be a useful (and affordable) addition to your students’ reading list.

When the editors at Adams came to me with the idea last year, they wanted a book that you could pick up and read a thousand words on a topic in astronomy and space science. They knew that readers see terms like “warp drive” and “black holes”. Readers hear about famous scientists like Edwin P. Hubble, Vera Rubin, Mike Brown, Copernicus, Galileo, and many others, but don’t always have the time to want to read textbooks to learn about these things.

So, my editors wanted me to give a fine first taste of astronomy.  They already had the title picked out, Astronomy 101, to let readers know the level of reading, and they had a subtitle picked out: “A Crash Course in the Science of Space”. And, the other subtitle “From the Sun and Moon to Wormholes and Warp Drive, Key Theories, Discoveries, and Facts about the Universe” tells the rest of what this book is about.

Those were the guiding principles I used to write the book. And, even with that guidance, it was tough. That’s because there’s SO MUCH to tell you about in astronomy and space science! I’ve been writing this blog since 2002 and I’ve never run out of things to write about!  So, figuring out what to write about, how much tell about it, and what I could leave out, was the hard part.

The fun part was simply writing down all the ideas I’ve had over the years about astronomy, the things I’ve learned in a lifetime of study and research and reading, and conceiving of a coherent way to introduce readers to the whys, wherefores, and personalities involved in doing astronomy.

I also had a fine group of readers—my astronomy posse—who sat in the background reading  each topic as I finished it. They patiently pointed out new findings, suggested rewrites in various places, and red-circled errors.  To them I owe a huge debt of gratitude—they are the experts in their fields and they were willing to help me tell the story of the science they love.

That’s the story behind Astronomy 101: A Crash Course in the Science of Space. I’m pleased that it’s finally out there, and I’d love it if you’d buy a copy. Review it online somewhere. Let me know what you think!  And, above all, come along with me as I explore the cosmos!