Astronomers puzzle over square galaxy

By Alan Boyle

We have the Hexagon on Saturn, the Red Rectangle nebula ? and now there's a square-shaped galaxy for astronomers to deal with.

"It's one of those things that just makes you smile because it shouldn't exist, or rather, you don't expect it to exist," Alister Graham, a professor at Australia's Swinburne University of Technology, said this week in a news release. "It's a little like the precarious Leaning Tower of Pisa, or the discovery of some exotic new species which at first glance appears to defy the laws of nature."

And yet, there it is: LEDA 074886, a square-looking dwarf galaxy that's part of the NGC 1407 Group of more than 250 galaxies in the constellation Eridanus, 70 million light-years away. The "emerald-cut galaxy" was spotted in a wide-field image taken using Japan's Subaru Telescope, and discussed in a research paper to be published in The Astrophysical Journal.

Most galaxies are either spheroidal, disk-shaped or irregular and lumpy, Graham noted. LEDA 074886 seems to have four rounded corners. Graham and his colleagues suspect that the galaxy is actually shaped like a shallow cylinder or an inflated disk, seen somewhat side-on. That would fit with observations from the Keck Telescope, which picked up the signs of a rapidly spinning, thin disk embedded in the galaxy's center.

"One possibility is that the galaxy may have formed out of the collision of two spiral galaxies," said Swinburne Professor Duncan Forbes, one of the study's co-authors. "While the pre-existing stars from the initial galaxies were strewn to large orbits, creating the emerald-cut shape, the gas sank to the midplane, where it condensed to form new stars and the disk that we have observed."

Studying the dynamics behind the square-looking shape could provide insights for modeling the development and interaction of other galaxies in collision, the researchers said.

"Curiously, if the orientation was just right, when our own disk-shaped galaxy collides with the disk-shaped Andromeda galaxy, about 3 billion years from now, we may find ourselves the inhabitants of a square-looking galaxy," Graham said. Maybe Huey Lewis was right: It's hip to be square.

Where in the Cosmos?
Three Cosmic Log correspondents were definitely hip to the square-shaped galaxy: The Subaru Telescope's view of the galaxy served as this week's "Where in the Cosmos" picture puzzle on the Cosmic Log Facebook page, and it took Paul Burley, Karl J. Martin and Charles Britten less than three minutes to come up with the answer.

The fact that Paul provided the geometrical answer first is particularly fitting, because he's the author of a book about cosmic geometry titled "The Sacred Sphere: Exploring Sacred Concepts and Cosmic Consciousness Through Universal Symbolism."

"I've found that a very specific spherical geometry may be expressed at all scales, from subatomic to universal, including the untold number of circular sacred symbols that all cultures throughout time and location have used to express relationships between each other, Earth, Cosmos and Creator," he told me in an email.

Sounds like Paul would enjoy "The New Universe and the Human Future," a book by Nancy Ellen Abrams and Joel Primack about new perspectives in cultural cosmology. I'll be sending him a copy, along with a pair of 3-D glasses and other goodies. Karl and Charles will be getting 3-D glasses as well. Click the "Like" button on the Cosmic Log Facebook page, and get ready for the next "Where in the Cosmos" contest in a week.

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In addition to Graham and Forbes, authors of "LEDA 074886: A Remarkable Rectangular-Looking Galaxy" include Lee Spitler, Thorsten Lisker, Ben Moore and Joachim Janz.

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding Cosmic Log's Google+ page to your circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.

Source: http://cosmiclog.msnbc.msn.com/_news/2012/03/23/10834579-astronomers-puzzle-over-square-galaxy

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