|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.
|L R G B color production was used to create this image.||
Minimum credit line: Adam Block/NOAO/AURA/NSF
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