Hubble spots spiral galaxy that shouldn’t exist

Astronomers using the Hubble Space Telescope have discovered the oldest known spiral galaxy, a 10.7-billion-year-old anomaly that by all rights shouldn’t exist. The galaxy was present in the early universe, about 3 billion years after the Big Bang, at a time when galaxies were still forming and normally looked clumpy and irregular. “The vast majority of old galaxies look like train wrecks,” said UCLA astronomer Alice E. Shapley, one of the discoverers of the unusual spiral galaxy. “Our first thought was, why is this one so different, and so beautiful?”

A team headed by astronomer David R. Law of the University of Toronto, a former graduate student at UCLA, used the Hubble to observe more than 300 distant galaxies and study their properties. One of the galaxies, named BX442, appeared unusual, and the team used the W. M. Keck Observatory in Hawaii to study it further. At first, the astronomers thought that it was an illusion of a spiral galaxy caused by the accidental alignment of two galaxies in the images. But studies of spectra from more than 3,600 locations in and around the galaxy revealed that it is, indeed, a rotating spiral galaxy, they reported in the journal Nature.

In fact, it is a so-called grand design spiral galaxy, which has prominent, well-formed spiral arms. “The fact that this galaxy exists is astounding,” Law said. “Current wisdom holds that such grand design spiral galaxies didn’t exist at such an early time in the history of the universe.”

The reason this one does exist may be the companion dwarf galaxy that appears to be merging with it. Computer simulations by co-author Charlotte Christensen of the University of Arizona suggest that such a merger could produce the spiral pattern observed. The calculations also suggest, however, that the merger would be rapid and that the spiral would disappear after a relatively brief 100 million years. Apparently, astronomers just happen to be looking at BX442 at the right time.


Copyright © 2012, Los Angeles Times

Hubble snaps view of dazzling celestial ‘snow angel’

Just in time for the holidays, the Hubble Space Telescope has snapped a spectacular view of a star-forming region in our Milky Way galaxy that looks like a snow angel in deep space.

This region, called Sharples 2-106 (or S106 for short) is located nearly 2,000 light-years away in the direction of the constellation of Cygnus (The Swan). The nebula is found in a relatively isolated part of the Milky Way, researchers said.

The S106 nebula measures several light-years across, and contains vast clouds of gas that resemble outstretched wings amidst an hourglass shape. The light from the glowing gas is colored blue in this image. A video and photo of the “snow angel” based on Hubble’s observations reveal a spectacular view of the cosmic sight.

Hubble’s view captures furious activity in the nebula, with ridges and ripples of super-hot gas mixing with the cooler interstellar medium. A massive young star, called Infrared Source 4 or IRS 4, is responsible for this turbulence, scientists said.

Radiation from IRS 4 makes the lobes of gas glow bright blue in the image, as they stretch outward from the central star. Luminous red veins also appear throughout the nebula creating intricate patterns.

A ring of dust and gas around the star squeezes the expanding nebula into its apparent hourglass shape. Faint light from the central star reflects off tiny dust particles, making the surrounding environment glow, and revealing darker filaments of dust beneath the blue dust clouds, the researchers said.

Astronomers have studied S106 and found several hundred brown dwarfs, which are cool, failed stars. When the nebula is viewed in infrared wavelengths, more than 600 of these misfit stars appear, scientists said.

Brown dwarfs weigh less than a tenth of our sun, and because of this low mass, they are unable to trigger enough energy through nuclear fusion. These cosmic objects encompass the S106 nebula in a small cluster, the researchers said.

S106 was the 106th object to be cataloged by astronomer Stewart Sharpless in the 1950s, the researchers said.

The newly released image was taken by Hubble in February. The composite picture was created by stitching together two images taken in infrared light.

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