Dr. Becky, seen in some of the Deep Sky videos, shows off a couple ring galaxies, and goes over some of the proposed hypothesis, some of the yet not generally accepted theories on how they form, and why all those have problems.
At about the 5 minute mark, she forgot to add "thousand" to the number of light years. "Whoops - had a brain typo half way through this video. Hoag's object dimensions should be 17 thousand light years, 75 thousand light years and 125 thousand light years - d'uh."
