Image of the Day: Mysterious Ring Galaxy 600-Million Light-Years Distant

 

The mystery is: Is this one galaxy or two? This question came to light in 1950 when astronomer Art Hoag discovered this odd extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older. Between the two is a gap that appears almost completely dark. How the object formed remains unknown. Possibilities include a galaxy collision billions of years ago and the gravitational affect of a central bar that has since vanished. Hoag's Object spans about 100,000 light years and lies about 600 million light years away toward the constellation of the Snake (Serpens). Coincidentally, visible in the gap (at about one o'clock) is yet another ring galaxy that likely lies far in the distance. Fascinating!

Image Credit: R. Lucas (STScI/AURA), Hubble Heritage Team, NASA

Comments

[Mike W.]

Wonder if dark matter is spacing out the gap?

[Bas van Gaalen]

@mike: if that would be the case, we wouldn't be able to see through and see the other more distant ring galaxy.

[Leon Elam]

This is so strange it makes me wonder if there are "reflections" involved, or some other event similar to optical effects.
I wonder if it's possible to look through a giant black hole, and see other universes on the other side? Maybe the image of the little ring galaxy is a "twin" of the large one, in another universe with the image being reflected, or drawn through?

[wildthang]

It is called a galaxy dog!!

[jay]

Why is it that both rings happen to be pointing our way so we can see them? Seems unlikely for that to happen. Are they more spherical, and we just see the edges better because the angle shows more stars in that plane?