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Solar Storms Could ‘Sandblast’ the Moon

December 6, 2011 Leave a comment

Credit: NASA/SDO

Credit: NASA/SDO

Solar storms and associated Coronal Mass Ejections (CMEs) can significantly erode the lunar surface according to a new set of computer simulations by NASA scientists. In addition to removing a surprisingly large amount of material from the lunar surface, this could be a major method of atmospheric loss for planets like Mars that are unprotected by a global magnetic field.

The research is being led by Rosemary Killen at NASA’s Goddard Space Flight Center, Greenbelt, Md., as part of the Dynamic Response of the Environment At the Moon (DREAM) team within the NASA Lunar Science Institute.

CMEs are basically an intense gust of the normal solar wind, a diffuse stream of electrically conductive gas called plasma that’s blown outward from the surface of the Sun into space. A strong CME may contain around a billion tons of plasma moving at up to a million miles per hour in a cloud many times the size of Earth.

Full Story: http://www.nasa.gov/topics/solarsystem/features/dream-cme.html

Milky Way’s Magnetic Fields Mapped with Highest Precision

December 6, 2011 Leave a comment

With a unique new all-sky map, scientists at MPA have made significant progress toward measuring the magnetic field structure of the Milky Way in unprecedented detail. Specifically, the map is of a quantity known as Faraday depth, which among other things, depends strongly on the magnetic fields along a particular line of sight. To produce the map, data were combined from more than 41,000 individual measurements using a novel image reconstruction technique. The work was a collaboration between scientists at the Max Planck Institute for Astrophysics (MPA), who are specialists in the new discipline of information field theory, and a large international team of radio astronomers. The new map not only reveals the structure of the galactic magnetic field on large scales, but also small-scale features that provide information about turbulence in the galactic gas.

All galaxies are permeated by magnetic fields, including our own Milky Way galaxy. Despite intensive research, the origin of galactic magnetic fields is still unknown. One assumes, however, that they are built up by dynamo processes in which mechanical energy is converted into magnetic energy. Similar processes occur in the interior of the earth, the sun, and – in the broadest sense – in the gadgets that power bicycle lights through peddling. By revealing the magnetic field structure throughout the Milky Way, the new map provides important insights into the machinery of galactic dynamos.

Full Story: http://www.mpa-garching.mpg.de/mpa/institute/news_archives/news1112_fara/news1112_fara-en.html

Massive Stars Are Born as Giants

December 6, 2011 Leave a comment

Astronomers from the University of Amsterdam have shown that forming massive stars are much bigger than grown-up massive stars. Their observations confirm the theory that, at the conclusion of the formation process, a massive star further contracts until it has reached a stable equilibrium. The results are published as a Letter in Astronomy & Astrophysics.

For many years it has been a challenge to obtain a clear spectrum of a massive star still in the process of formation. The reason being that forming stars are deeply embedded inside their parental clouds that obscure their birthplaces from view. Recently, a spectrum has been obtained of the young star B275 in the Omega Nebula (M17) with the new, powerful spectrograph X-shooter on ESO’s Very Large Telescope in Chile. This has resulted in the first firm spectral classification of a massive star on its way to the main sequence. The spectrum indicates that B275 is about three times as large as a normal main-sequence star about 7 times more massive than our Sun. This is in good agreement with the predictions of current star formation models.

Full Story: http://astronews.us/2011-12-06-1836.html

Hubble Racks Up 10,000 Science Papers

December 6, 2011 Leave a comment

NASA’s Hubble Space Telescope has passed another milestone in its 21 years of exploration: the 10,000th refereed science paper has been published. This makes Hubble one of the most prolific astronomical endeavors in history.

For the past 21 years thousands of astronomers around the world in over 35 countries have been engaged in Hubble research. Outside of the United States, the top five nations publishing the most Hubble findings are the United Kingdom, Germany, Italy, France, and Spain.

The papers are based on Hubble observations that cover nearly every frontier in astronomy. The five top referenced science papers are, in order: the search for distant supernovae used to characterize dark energy; the precise measurement of the universe’s rate of expansion; the apparent link between galaxy mass and central black hole mass; early galaxy formation in the Hubble Deep Field; and the evolutionary models for low-mass stars and brown dwarfs.

Full Story: http://hubblesite.org/newscenter/archive/releases/2011/40/image/a/

New Sub-mm Camera Reveals Dark Side of Universe

December 6, 2011 Leave a comment

A new camera that will revolutionise the field of submillimetre astronomy has been unveiled on the James Clerk Maxwell Telescope (JCMT) in Hawaii SCUBA-2 is far more sensitive and powerful than previous instruments and can map areas of the sky hundreds of times faster.

SCUBA-2 will provide unprecedented information on the early life of stars – normally obscured by the remains of the very dust and gas cloud that collapsed under its own gravity to form the star.

“When you look up at the stars, you only see the light they are emitting in the visible part of the spectrum. Many galaxies, including our own Milky Way, contain huge amounts of cold dust that absorbs visible light and these dusty regions just look black when seen through an optical telescope. The absorbed energy is then re-radiated by the dust at longer, submillimetre, wavelengths”, explains Professor Gary Davis, Director of the JCMT. “SCUBA-2 has been designed to detect extremely low energy radiation in the submillimetre region of the spectrum. To do this, the instrument itself needs to be even colder. The detectors inside SCUBA-2 have to be cooled to only 0.1 degree above absolute zero [–273.05°C], making the interior of SCUBA-2 colder than anything in the Universe that we know of!”

Full Story: http://www.stfc.ac.uk/News%20and%20Events/38072.aspx

New NASA Dawn Visuals Show Vesta’s ‘Color Palette’

December 6, 2011 Leave a comment

Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Vesta appears in a splendid rainbow-colored palette in new images obtained by NASA’s Dawn spacecraft. The colors, assigned by scientists to show different rock or mineral types, reveal Vesta to be a world of many varied, well-separated layers and ingredients. Vesta is unique among asteroids visited by spacecraft to date in having such wide variation, supporting the notion that it is transitional between the terrestrial planets — like Earth, Mercury, Mars and Venus — and its asteroid siblings.

In images from Dawn’s framing camera, the colors reveal differences in the rock composition associated with material ejected by impacts and geologic processes, such as slumping, that have modified the asteroid’s surface. Images from the visible and infrared mapping spectrometer reveal that the surface materials contain the iron-bearing mineral pyroxene and are a mixture of rapidly cooled surface rocks and a deeper layer that cooled more slowly. The relative amounts of the different materials mimic the topographic variations derived from stereo camera images, indicating a layered structure that has been excavated by impacts. The rugged surface of Vesta is prone to slumping of debris on steep slopes.

Full Story: http://www.jpl.nasa.gov/news/news.cfm?release=2011-375

Watch the Dawn Eclipse of the Moon, Dec. 10, 2011

December 6, 2011 Leave a comment

Credit: Sky & Telescope photo by Richard Tresch Fienberg

Credit: Sky & Telescope photo by Richard Tresch Fienberg

If you’re anywhere in central or western North America, mark your calendar to get up before dawn this Saturday, December 10, 2011. That morning the full Moon goes through its last total eclipse until 2014.

The farther west you are in the U.S. or Canada, the better you’ll be set up for the show. If you’re in the Pacific time zone you can watch the Moon slip into Earth’s shadow completely, while the Moon is sinking low in the west-northwestern sky and dawn is brightening. In the Pacific Northwest and westernmost Canada, you can even see the Moon start to emerge from our planet’s shadow after the total eclipse is over — until moonset and sunrise end the show.

From roughly Arizona to the Dakotas, the Moon sets while it’s still totally eclipsed — though horizon obstructions and the brightening dawn may end your view somewhat before then.

Full Story: http://www.skyandtelescope.com/about/pressreleases/Watch-the-Dawn-Eclipse-of-the-Moon-Decnbsp10nbsp-2011-134917183.html