Why is the Milky Way a bared galaxy?

[Imax]

Why is the Milky Way a barred galaxy?

http://en.wikipedia.org/wiki/Barred_spiral_galaxy

http://upload.wikimedia.org/wikipedia/commons/8/89/236084main_MilkyWay-full-annotated.jpg

 

[Chalnoth]

Why is the Milky Way a barred galaxy?

http://en.wikipedia.org/wiki/Barred_spiral_galaxy

http://upload.wikimedia.org/wikipedia/commons/8/89/236084main_MilkyWay-full-annotated.jpg

That Wikipedia article is probably about as good as you're going to get as an explanation.

 

[Imax]

Where’s Sagittarius A*

http://en.wikipedia.org/wiki/Sagittarius_A*

in this animation:

http://upload.wikimedia.org/wikipedia/commons/8/89/236084main_MilkyWay-full-annotated.jpg

 

[TheTechNoir]

One thing I do know for sure is that it is expected that after colliding with Andromeda it will become an elliptical galaxy. I think the same is true, or at least believed to be true for most if not all spiral or spiral barred galaxies after enough collisions with similar sized/mass galaxies.

This leads me to believe that it has to do with the age of a galaxy, or more precisely how many merges it has had in it's life time. I am not certain of this part but it is my educated guess based upon this that most if not all galaxies start off as spiral galaxies and ours is just younger in that regard. I wouldn't post a response with a guess normally but I did give factual information as well, and am just giving my guess to continue the chain of logic. I'm going to research that now though. As for the barred aspect, I haven't a clue.

 

[Imax]

Barred galaxy = merger of 2 galaxies?

 

[Radrook]

Barred galaxy = merger of 2 galaxies?

Excerpt:


The bars are mostly stars (usually), unlike spiral arms (which have lots of gas and dust besides stars). The formation and evolution of bars is an active area of research in astronomy today; they seem to form from close encounters of the galaxy kind (galaxy near-collisions), funnel gas into the central bulge (where the super-massive black holes there snack on it), and are sustained by the same density waves which keep the arms alive.
http://www.universetoday.com/40300/barred-spiral-galaxy/