Look closely at the serpent constellation slithering through the northern sky, and you might see a galaxy within a galaxy within a galaxy.
This cosmic turducken is known as Hoag’s object, and it has befuddled stargazers since astronomer Arthur Hoag discovered it in 1950.
The object in question is a rare, ring-shaped galaxy measuring some 100,000 light-years across (slightly larger than the Milky Way) and located 600 million light-years from Earth. In a recent image of the oddball object taken by the Hubble Space Telescope and processed by geophysicist Benoit Blanco, a bright ring of billions of blue stars forms a perfect circle around a much smaller and denser sphere of reddish stars. In the dark gap between the two stellar circles, another ring galaxy — much, much farther away from us — peeks out to say hello.