Universe Sandbox

General Category => Astronomy & Science => Topic started by: Arata on November 16, 2009, 02:36:26 PM

Title: What if the Milky Way is a RING galaxy?
Post by: Arata on November 16, 2009, 02:36:26 PM

I was wondering, What if our galaxy isn't a full spiral, but has a ring of stars orbiting it's center, and we are outside of that ring, which is why we see a lot of dust? ???
I'm just wondering, since we never have been out of the galaxy to see what it really looks like.
I just want to know. I mean sure, there could be distortion on the edges of our galaxy that makes a ring like formation, but what if the ENTIRE galaxy is a ring?

Title: Re: What if the Milky Way is a RING galaxy?
Post by: Chaotic Cow on November 16, 2009, 05:58:16 PM

Can you show me what you mean?

Title: Re: What if the Milky Way is a RING galaxy?
Post by: Arata on November 16, 2009, 08:05:19 PM

Here's an image I made to show you what I mean (yellow dot indicates Sun's position.):

Title: Re: What if the Milky Way is a RING galaxy?
Post by: Dan Dixon on November 16, 2009, 10:52:05 PM

Quote from: Arata on November 16, 2009, 02:36:26 PM

What if our galaxy isn't a full spiral, but has a ring of stars orbiting it's center...

Nice image. Well done.

It's interesting idea, but scientists are quite certain that our galaxy is a barred spiral galaxy.
http://en.wikipedia.org/wiki/Milky_Way#Spiral_arms

"Observations presented in 2008 by Robert Benjamin of the University of Wisconsin-Whitewater suggest that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum-Centaurus arm."

Here is information about the image that is used in Universe Sandbox to depict our galaxy:
http://www.spitzer.caltech.edu/Media/releases/ssc2008-10/ssc2008-10b.shtml

Title: Re: What if the Milky Way is a RING galaxy?
Post by: Chaotic Cow on November 17, 2009, 06:22:10 AM

So they think we are in a Spiral Bar Center Galaxy with 2 Major Arms and a few minor arms.

Title: Re: What if the Milky Way is a RING galaxy?
Post by: witold on November 17, 2009, 11:09:32 AM

We have spiral-ringed galaxy

Title: Re: What if the Milky Way is a RING galaxy?
Post by: Arata on November 17, 2009, 03:14:01 PM

I would like to know how the know our galaxy is a BARRED spiral.

Title: Re: What if the Milky Way is a RING galaxy?
Post by: atomic7732 on November 17, 2009, 03:36:49 PM

Because the way they tell distance of stars (parallax) and where they are placed they can make a virtual image of distances and... Tah dah!

I was gonna say: "How do you tell distance of a virtual sound?"
Edit: Although that ones kind of... more complicated...

Title: Re: What if the Milky Way is a RING galaxy?
Post by: Dan Dixon on November 17, 2009, 07:43:55 PM

Quote from: Arata on November 17, 2009, 03:14:01 PM

I would like to know how the know our galaxy is a BARRED spiral.

That is a really great question. It's a good strategy to ask how we know something and not just believe it because someone told you that's they way it is.

Similar to what NeutronStar said, scientists are able to determine the distance of the stars in our galaxy using various techniques (including parallax) are able to plot out those distances to see that our galaxy has 2 main arms and a barred center.

The short answer is from observation. If the galaxy was a ring, like how you depicted it, the data would look very different.

These sites answers your question specifically:
http://www.astronomycafe.net/qadir/q2213.html (uses an outdated image of our galaxy showing four main arms)
http://curious.astro.cornell.edu/question.php?number=622

Title: Re: What if the Milky Way is a RING galaxy?
Post by: monmarfori on November 18, 2009, 02:43:03 PM

Spirals are not ringed. only polar ring galaxies and ring galaxies.