Hoag's Galaxy: PGC 54559

Click on image for larger version.

Perhaps this object should have been placed with the other Planetary Nebulae found in our galaxy? You would not be the first person to make the suggestion. In 1950 when astronomer Art Hoag noticed this galaxy on a survey of plates, he remarked that it first seemed like a planetary nebula- but the size of the nucleus and brightness of the ring strongly suggested otherwise. 50 years later a much better understanding of this object came to pass when astronomers used the Hubble Space Telescope to peer more intensively (and with wonderous resolution) at Hoag's Galaxy. At 600 million light years away, not even a 2.5m space telescope can resolve many of the features of this galaxy that would help conclusively unravel the mystery of this galactic ring. Today, favored explanations describe this galaxy as being the interaction and later accretion of material from another galactic interloper. The special circumstances necessary to create a relatively long-lived ring of starforming material around an older elliptical galaxy makes this an extremely rare object. Perhaps the most important idea to take away from the image on the left is that no longer do astronomers think that galaxies are formed in quiescence and isolation- instead galaxies regularily interact strongly and it is this dynamical property of the universe which leads to the morphological spectrum of galaxies we observe. For more information please visit the following link about Hoag's Galaxy and others of its type. Be certain to note the incredible "fractal" nature of the universe in the HST image. There is a ring galaxy in the background- seen through the ring of this weird wonder.

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Updated: 04/01/2004