If you look carefully at about one o'clock, you can see a galaxy which lies far in the distance. The picture was taken using the hubble space telescope. N.A.S.A
Hoag's Object is often referred to as a peculiar galaxy rather than Elliptical or Spiral.
It is not unique, there are others, an example of another ring galaxy is the Cartwheel Galaxy. Hoag's Object remains as one of the more perfect circular ring galaxies out there.
The outer ring has hot Blue giant stars whilst the inner ring has older Red Giant Stars.
Hoag thought it might be an optical illusion caused gravitational lensing but when more advanced telescopes were used, it was shown not to be the case.
There are a number of theories as to why the galaxy looks the way it does. A common theme between the different versions is that it was caused by a collision of two galaxies. Instead of creating a tail such as that in the Tadpole Galaxy, it has created the effect that we see. Medium
Hoag's Object Facts, Picture, Map & How to Find - Universe Guide
Hoag's Object: A Ring Galaxy
September 26, 2018