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Our Milky Way Galaxy – As You’ve Never Seen It Before

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By Terry Devitt – University of Wisconsin – Madison

With the help of NASA’s Spitzer Space Telescope , astronomers have conducted the most comprehensive structural analysis of our galaxy and have found tantalizing new evidence that the Milky Way is much different from your ordinary spiral galaxy.

The survey using the orbiting infrared telescope provides the fine details of a long central bar feature that distinguishes the Milky Way from more pedestrian spiral galaxies.

“This is the best evidence ever for this long central bar in our galaxy,” says Robert Benjamin, a UW-Madison professor of and a senior author of a paper describing the new work in an upcoming edition of Astrophysical Journal Letters, a leading astronomy journal.

Using the orbiting infrared telescope, the group of astronomers surveyed some 30 million stars in the plane of the galaxy in an effort to build a detailed portrait of the inner regions of the Milky Way. The task, according to Churchwell, is like trying to describe the boundaries of a forest from a vantage point deep within the woods: “This is hard to do from within the galaxy.”

Spitzer’s capabilities, however, helped the astronomers cut through obscuring clouds of interstellar dust to gather infrared starlight from tens of millions of stars at the center of the galaxy. The new survey gives the most detailed picture to date of the inner regions of the Milky Way.

“We’re observing at wavelengths where the galaxy is more transparent, and we’re bringing tens of millions of objects into the equation,” says , the lead author of the new study and a professor of physics at the University of Wisconsin-Whitewater.

The possibility that the Milky Way Galaxy has a long stellar bar through its center has long been considered by astronomers, and such phenomena are not unheard of in galactic taxonomy. They are clearly evident in other galaxies, and it is a structural characteristic that adds definition beyond the swirling arms of typical spiral galaxies.

The new study provides the best estimates for the size and orientation of the bar, which are far different from previous estimates.

It shows a bar, consisting of relatively old and red stars, spanning the center of the galaxy roughly 27,000 light years in length – 7,000 light years longer than previously believed. It also shows that the bar is oriented at about a 45-degree angle relative to a line joining the sun and the center of the galaxy.

Previously, astronomers debated whether a presumed central feature of the galaxy would be a bar structure or a central ellipse – or both. The new research, the Wisconsin astronomers say, clearly shows a bar-like structure.

“To date, this is the best evidence for a long bar in our galaxy,” Benjamin asserts. “It’s hard to argue with this data.”

The Spitzer Space Telescope was lofted into orbit in August of 2003. It consists of a telescope and three science instruments, including the Infrared Array Camera, the primary instrument used for the new survey, known as GLIMPSE for Galactic Legacy Mid-Plane Survey Extraordinaire.

NASA’s (JPL), Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington, D.C. Science operations are conducted at the Spitzer Science Center in Pasadena. JPL is a division of the California Institute of Technology.

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This was such a well written piece that I felt there was no need to rewrite it for Blogcritics. Very nice job Mr Devitt! Many thanks to the University Of Wisconsin-Madison for the high resolution image [photograph, neh?].

Also posted at VERMONT SPACE
( That’s worth looking at, eh?)

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About Bennett Dawson

  • http://victorplenty.blogspot.com Victor Plenty

    Photograph!? Wow! I didn’t know we’d gotten any probes far enough out to take a picture quite like that one!

    Nitpicking over terminology aside, thanks for covering this story. I considered posting on it myself last night, but realized I lack the hosting space to provide suitably large images, and I didn’t want to use bandwidth draining deep links to images on other sites like Wikipedia, NASA, or the University of Wisconsin’s site.

    Glad to see I’m not the only one who thinks the new image of our galaxy’s shape is wicked cool.

  • http://alienboysworld.blogspot.com alienboy

    Yeah, I almost posted on this too, but then I remembered that BlogCritics had a Space Correspondent and didn’t want to cramp their style.

    Isn’t that a fantastic image?! When I saw it yesterday I couldn’t believe the detail. I guess it must be an artistic creation though, not an actual image, given the point of view, lol

  • Bennett

    Ahhhhhhhhhhhh! Okay folks, I’m a’gunna change that word to “image” onacount that Victor busted me on it.

    ;-]

    Funny though, my wife asked me and I described the process and said “of course it’s NOT a photograph, wicked too far to send a spacecraft, eh?”

    The shame, the shame…

    Yeah, it’s really a great image, and it blows my mind that we humans can see with our tools and create this “picture” of our galaxy.

  • Bennett

    Alienboy – No, it is a computer generated image from actual data gathered by the Spitzer Telescope.

    But Fellas! Jump on this stuff if you have the thought! It’s not like I’m getting paid by the word or anything.

    In fact, there are about five other science/space developments that should be brought to BC and I’m finding it hard to devote the time.

    It’s harvest time, still have to work, and the lovely wife is….. yep, she IS. So that complicates things a tad.

    Go men go!

  • Bennett

    Victor – after the education I received from Mr. Cowing, I’m careful to host all images except for NASA images.

    After all, I do pay for those, AND the website. However, if I want to resize them and such, I end up hosting them anyway.

  • Balletshooz

    That new shape is probably caused by the thousands of giant black holes they found at the center of the galaxy using the chandra x-ray telescope.

  • http://victorplenty.blogspot.com Victor Plenty

    Yes, I recall your exchange with Mr. Cowing. His initial approach irked me, but by the end of it I found he’d made a valid point.

    Your point here is valid too, Bennett. NASA is funded by us, and they’ve been accustomed to getting lots of traffic ever since Pathfinder landed on Mars, so I suppose I could always link to their images.

    Now I just have to teach myself how to use images efficiently and aesthetically.

  • Bennett

    Victor – He turned out to be a pretty nice guy. Spoke with him on the phone minutes after that episode concluded, and we got on okay.

    Image use is pretty easy. Email me if you need a pointer or two when you’re putting together a post.

    Regards!

  • gonzo marx

    nice book choice Bennett…

    and excellently informative article, as per usual

    /golfclap

    oh yes..thanks for the new desktop wallpaper “image” as well

    w00t!

    i may actually be in your neck of the woods saturday…

    just a thought

    Excelsior!

  • http://journals.aol.com/vicl04/VictorLana/ Victor Lana

    I think just looking at that amazing depiction of our galaxy and seeing the arrow pointing to where our sun is in the infinite array, well it’s not only mind boggling, but just a real qualifier as to our place in the universe.

  • http://selfaudit.blogspot.com Aaman

    Can I get a version WITHOUT the arrow?:)

  • gonzo marx

    or switch it to say “you are here” ??

    Excelsior!

  • http://selfaudit.blogspot.com Aaman

    I wish we were closer to the galactic core, though – by Orion’s Belt! What I would give to see the light of a thousand suns!

  • Bennett

    Here’s a link to UWM. I looked, and visited the JPL Spitzer site, but it just links back to the UWM site.

    I’d like a version without the arrow as well. The image in this post is the high res version from the UWM site, resized to fit BC’s collumn. The high res image is 3.? meg and could be edited with photoshop or Paintshop to remove the arrow.

    Thanks for the kind works folks! I am as stunned as you. What a great time we live in, eh?

    Bennett

  • http://victorplenty.blogspot.com Victor Plenty

    The arrow seems slightly inaccurate, though. It points at a spot in between two of the spiral arms. I’ve always thought we’re actually inside one of the spiral arms.

    But maybe this is just a counter-intelligence maneuver to keep the aliens from locating us.

  • http://www.seti.org VogonLeaderOne

    Drat! Now we need to re-target those DeathStars – and fill out those forms in quintuplicate!

    Thanks Mr Plenty – you are a useful fifth columnist

  • http://victorplenty.blogspot.com Victor Plenty

    Excellent! You fell for my ploy, and now we’ll finally be rid of that pesky planet over there inside the spiral arm.

  • Dan

    Just for some interesting spatial perspective to highlight our insignificance: If our sun were the size of a basketball, the earth would be about the size of a BB. the distance between them would be about the length of a regulation basketball court. 90+ feet. Pluto, at about 2/100 th’s of an inch in diameter, would be about 2/3rd’s mile from the “basketball”.

    The nearest “basketball” to ours is Alpha Centauri, actually a star system with 3 stars, it would be 4 or 5 thousand miles from our basketball sized sun.

    It’s not very crowded in space.

  • Adam

    wow… we’re so insiginificant… if thats our sun… that tiny little dot in that huge galaxy… and there’s billions of those galaxies… God is huge…