Chuck Bednar for redOrbit.com – Your Universe Online
Earlier this month, the Hubble Space Telescope captured an image of NGC 7814, a galaxy also known as the “Little Sombrero,” due to its unique shape. It has a bright central bulge and a bright halo of glowing gas that extends outwards into space.
NGC 7814, also known as UGC 8 or Caldwell 43, is a spiral galaxy located roughly 40 million light-years away in the constellation Pegasus. Its dusty spiral arms are comprised of material that absorbs and blocks light from the galactic center behind it, making them look like they are dark streaks, and Hubble’s new image features a view of the galaxy from its edge.
According to NASA, galaxies can come in many different shapes and sizes, and their orientation relative to us can sometimes make them look even more bizarre than usual. The new photo of the so-called “Little Sombrero” got us thinking: What are some of the most unusual galaxies ever discovered by astronomers? Here are a few of our favorites.
NGC 4594 (Credit: NASA/Hubble Heritage Team)
Of course, you can’t mention the “Little Sombrero” without bringing up its namesake, an unbarred spiral galaxy known as NGC 4594, Messier Object 104 and the Sombrero Galaxy that is located 28 million light-years from Earth in the constellation Virgo.
Both NGC 4594 and NGC 7814 earned their nicknames because their large central bulges and lengthy dust lane make it resemble one of the popular wide-brimmed Mexican hats. The galaxy’s dust lane is actually a symmetrical ring that encloses the bulge, and experts believe the ring may also contain the majority of NGC 4594’s cold molecular gas.
Hoag's Object (Credit: R. Lucas (STScI/AURA), Hubble Heritage Team, NASA)
Discovered in 1950 by astronomer Art Hoag, Hoag’s Object almost looks like it is two separate galaxies – an outer one made up primarily of bright blue stars, and an inner one that resembles a ball comprised mostly of much older, redder stars. Between the two objects is a gap that appears to be almost completely dark, and how this unusual object formed remains unknown.
In July 2001, Hubble obtained an image of the object that captured it in greater detail, and more recently radio waves revealed that it had not accreted a smaller galaxy within the past one billion years. Hoag’s Object is located approximately 600 million light years away near the constellation Serpens (the Snake), and covers a span of about 100,000 light years, according to NASA.
Arp 87 (Credit: NASA/ESA/Hubble Heritage Team (STScI / AURA)
Located about 300 million light-years from Earth in the Leo constellation, Arp 87 is not one but two galaxies (NGC 3808A and NGC 3808B) that are interacting with one another. The formation stretches for more than 75,000 light-years, and the two galaxies are joined together in what the US space agency refers to as “a cosmic bridge of stars, gas, and dust.”
“The bridge is strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity,” NASA added. NGC 3808A, the galaxy on the right, shows several young blue star clusters in the midst of star formation, while the one on the left, NGC 3808B, appears to be surrounded by an unusual polar ring.
Southern Pinwheel Galaxy (Credit: NASA/ESA/the Hubble Heritage Team/STScI/AURA/William Blair, Johns Hopkins University
One of the closest and brightest barred spiral galaxies in the skies, the Southern Pinwheel Galaxy (also known as Messier 83 and NGC 5236) is located approximately 15 million light-years from Earth in the constellation Hydra. It can be viewed using binoculars, and doing so is highly recommended, as astronomers have observed at least a half-dozen supernovae in this formation.
Discovered roughly a quarter of a century ago, the Southern Pinwheel Galaxy boasts a unique, whirlpool-like feature that has a bold color scheme blending pink and purple. The pink color is said to be the result of new stars forming in the system, a process which gives off tremendous amounts of UV radiation that is absorbed by the surrounding gas and dust to create the color.
The Porpoise Galaxy (Credit: NASA/ESA/The Hubble Heritage Team (STSci/AURA))
Finally, we come to the Porpoise Galaxy, which like Arp 87 is actually a combination of two different galaxies. The upper galaxy, NGC 2936, was likely a regular spiral galaxy until a few hundred million years ago, when it ventured too close to the elliptical galaxy beneath it, giving the galactic formation collectively known as Arp 142 its distinctive appearance.
Apr 142 is located about 300 million light years away near the constellation of the Water Snake (Hydra), and in roughly one billion years, the two galaxies are expected to finally merge into one larger entity. Until then, however, astronomy enthusiasts can continue to observe one of the most unique galactic formations in the night sky, complete with its bright blue streams of stars.
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