But this time, this inconvenient truth has nothing to do with our planet or how we’re treating it. According to results that were presented to the American Astronomical Society meeting in Austin, Texas last Tuesday, a spiral galaxy has been confirmed to have a pair of arms that are winding in the opposite direction from most galaxies.
“While the existence of a galaxy with a pair of ‘backward’ arms may seem like an inconvenient truth to many, our latest analysis indicates it is, nonetheless, a reality,” says Drs. Gene Byrd, professor of astronomy at The University of Alabama.
The galaxy known as NGC4622, and sitting 200 million light years away in the constellation Centaurus, was the focus of a 2001 Hubble Telescope image. The team – including Byrd, as well as Ron Buta, from The University of Alabama; Tarsh Freeman, Bevill Community College; and Dr. Sethanne Howard, retired from the U.S. Naval Observatory – used a Fourier component image method to further analyze the photo.
From within the photo, they found evidence of a pair of clockwise spiraling arms, that had hitherto been hidden.
Spiral arm pairs seen within galaxies are traditionally thought to trail; meaning that they wind outward, opposing the direction of the rotation of the disk material. Leading arms however, such as the pair found in NGC4622, oppose this tradition, instead folding outward in the same direction as the rotation of the galaxy’s disc.
“Contrary to conventional wisdom, with both an inner counter-clockwise pair and an outer clockwise pair of spiral arms, NGC4622 must have a pair of leading arms,” Byrd said. “With two pairs of arms winding in opposite directions, one pair must lead and one pair must trail. Which way is which depends on the disk’s rotation. The outer clockwise pair must be the leading pair if the disk turns clockwise. Alternatively, the inner counter clockwise pair must be the leading pair if the disk turns counter clockwise.”
Now things start to get confusing… er.
The team that found the clockwise pair of arms also found several other arms that, in all reality, confuse the hell out of me. Included is an outer clockwise single arm, which was previously hidden by the stronger outer clockwise pair, and a previously indentified inner single counterclockwise arm.
All of this (apparently) confirms that the galaxy must have a single leading arm; and, that the outer clockwise arm muse be the leading arm if the disk turns clockwise, and that the inner counter clockwise arm must be the leading arm if the disk turns counterclockwise.
“Two independent methods now indicate that NGC4622’s arms do indeed behave in a very unusual fashion, with the outer arms winding outward in the same direction the galaxy turns,” said Byrd, referring to a 2002 revelation stating the same thing, but which was highly criticized.
Joshua Hill, a Geek’s-Geek from Melbourne, Australia, Josh is an aspiring author with dreams of publishing his epic fantasy, currently in the works, sometime in the next 5 years. A techie, nerd, sci-fi nut and bookworm.
