> Many of the details of the galaxy remain a mystery, foremost of which is how it formed. So-called "classic" ring galaxies are generally formed by the collision of a small galaxy with a larger disk-shaped galaxy. [...] However, there is no sign of any second galaxy that would have acted as the "bullet", and the likely older core of Hoag's Object has a very low velocity relative to the ring, making the typical formation hypothesis quite unlikely. [...]
> A few other galaxies share the primary characteristics of Hoag's Object, including a bright detached ring of stars, but their centers are elongated or barred, and they may exhibit some spiral structure. While none match Hoag's Object in symmetry, this handful of galaxies are known to some as Hoag-type galaxies.
I offer no hypothesis of my own (not least because this is outside my field), but it does seem odd to me as well. Is it possible that our mechanical intuition fails at such a large scale?
"We don't."
Astronomy is more comfortable nowadays. It can be done from anywhere.
(i know the article mentions others, so this might not hold up to a full cataloging of our night sky)
