Jan 11, 2011
Space Oddity
Image Credit: NASA, ESA, W. Keel (University of Alabama) and the Galaxy Zoo Team
In this image taken by the Hubble Space Telescope, an unusual, ghostly green blob of gas appears to float near a neighboring spiral galaxy. The bizarre object, dubbed Hanny's Voorwerp (Hanny's Object in Dutch), is the only visible part of a 300,000-light-year-long streamer of gas stretching around the galaxy, called IC 2947. The greenish Voorwerp is visible because a beam of light from the galaxy's core illuminated it. This beam came from a quasar--a bright, energetic object powered by a black hole. The quasar may have turned off about 200,000 years ago. This Hubble view uncovers a pocket of star clusters, the yellowish-orange area at the tip of Hanny's Voorwerp. The star clusters are confined to an area that is a few thousand light- years wide. The youngest stars are a couple of million years old. The Voorwerp is the size of our Milky Way galaxy, and its bright green color is from glowing oxygen. An interaction between IC 2947 and another galaxy about a billion years ago may have created Hanny's Voorwerp and fueled the quasar. The Hubble image shows that IC 2947 has been disturbed, with complex dust patches, warped spiral arms, and regions of star formation around its core. These features suggest the aftermath of a galaxy merger. The bright spots in the central part of the galaxy are star-forming regions. The small, pinkish object to the lower right of IC 2397 is an edge-on spiral galaxy in the background. The image was made by combining data from the Advanced Camera for Surveys and the Wide Field Camera 3. The ACS exposures were taken April 12, 2010; the WFC3 data, April 4, 2010. Image Credit: NASA, ESA, W. Keel (University of Alabama) and the Galaxy Zoo Team
Jan 13, 2011
Princess Rhea and Her Ladies in Waiting
Image credit: NASA/JPL/SSI
Princess Rhea and Her Entourage
NASA's Cassini spacecraft captured this image showing Saturn's icy moon Rhea taking center stage, with cameo appearances by Saturn's rings and three clearly visible moons. In this image, Dione appears just above Rhea. Tethys is the larger circle toward the upper left and Epimetheus is the smaller dot to the left of Rhea. Prometheus is to the left of Dione, but barely distinguishable as a speck embedded in the rings. This wide-angle image was taken on Jan. 11, 2011 from a distance of approximately 60,000 kilometers away (37,000 miles).
Jan 14, 2011
Henize 2-10, a Dwarf Starburst Galaxy

The combined observations from multiple telescopes of Henize 2-10, a dwarf starburst galaxy located about 30 million light years from Earth, has provided astronomers with a detailed new look at how galaxy and black hole formation may have occurred in the early Universe. This image shows optical data from the Hubble Space Telescope in red, green and blue, X-ray data from NASA's Chandra X-ray Observatory in purple, and radio data from the National Radio Astronomy Observatory's Very Large Array in yellow. A compact X-ray source at the center of the galaxy coincides with a radio source, giving evidence for an actively growing super massive black hole with a mass of about one million times that of the sun.
Stars are forming in Henize 2-10 at a prodigious rate, giving the star clusters in this galaxy their blue appearance. This combination of a burst of star formation and a massive black hole is analogous to conditions in the early Universe. Since Henize 2-10 does not contain a significant bulge of stars in its center, these results show that super massive black hole growth may precede the growth of bulges in galaxies. This differs from the relatively nearby Universe where the growth of galaxy bulges and super massive black holes appears to occur in parallel.
A paper describing these results was published online in Nature on January 9th, 2011 by Amy Reines and Gregory Sivakoff of the University of Virginia, Kelsey Johnson of the University of Virginia and the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia and Crystal Brogan also of NRAO in Virgina.
Credits: X-ray (NASA/CXC/Virginia/A.Reines et al); Radio (NRAO/AUI/NSF); Optical (NASA/STScI)
A Torrent of Star Formation
Credits: NASA/CXC/Wesleyan Univ./R. Kilgard et al
A new Chandra X-ray Observatory image of Messier 82, or M82, shows the result of star formation on overdrive. M82 is located about 12 million light years from Earth and is the nearest place to us where the conditions are similar to those when the Universe was much younger with lots of stars forming. M82 is a so-called starburst galaxy, where stars are forming at rates that are tens or even hundreds of times higher than in a normal galaxy.