Archive for August, 2012

Hubble Spotted A Supernova In NGC 5806

August 31, 2012 1 comment

A new image from the NASA/ESA Hubble Space Telescope shows NGC 5806, a spiral galaxy in the constellation Virgo (the Virgin). It lies around 80 million light years from Earth. Also visible in this image is a supernova explosion called SN 2004dg.

The exposures that are combined into this image were carried out in early 2005 in order to help pinpoint the location of the supernova, which exploded in 2004. The afterglow from this outburst of light, caused by a giant star exploding at the end of its life, can be seen as a faint yellowish dot near the bottom of the galaxy.

NGC 5806 was chosen to be one of a number of galaxies in a study into supernovae because Hubble’s archive already contained high resolution imagery of the galaxy, collected before the star had exploded. Since supernovae are both relatively rare, and impossible to predict with any accuracy, the existence of such before-and-after images is precious for astronomers who study these violent events.

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Solor Storms Can Destabilize Power Grids At Midlatitudes

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The Sun is capable of disrupting electrical systems on Earth in a variety of ways, from solar flares and coronal mass ejections to proton storms. Typically, it is only objects far above the Earth’s surface, or systems at high altitudes at polar latitudes, that are considered at risk except during the most powerful storms. Notable recent examples include solar activity during March 1989 and October 2003 (the “Halloween Storms”), which knocked out power in Quebec, Canada, and Sweden, respectively. Research by Marshall et al., however, finds that even a moderate event can have destructive effects far from the typical regions of concern.

At 1:20 UT on 6 November 2001, a high-density pocket of solar wind, 18 nanoPascals above the background pressure, sped past the Solar and Heliospheric Observatory (SOHO) satellite, which was orbiting 197 Earth radii above the Earth toward the Sun. In half an hour, this high-pressure wave traveled more than a million kilometers (620,000 miles) to the Earth’s magnetopause. The high-pressure pulse induced currents both in the magnetopause and in power lines across New Zealand, causing alarms to be tripped and a transformer to fail catastrophically. Extending from 35 degrees South to 46 degrees South, New Zealand is typically considered outside the region susceptible to such solar activity. A Northern Hemisphere equivalent would be a zone extending from Maine to North Carolina. The authors find currents of up to 27.4 amperes in transformer earth lines that were supposed to be neutral. For comparison, the Halloween Storms 2 years later caused peak currents of 23.4 amperes and no serious damage, though the authors suggest that this may have been due to damage prevention measures implemented following the 2001 event.

Source: Space Weather

Major Astronomy Meeting Draws To A Close

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The XXVIIIth General Assembly of the International Astronomical Union (IAU) ends today in Beijing, China. One of the largest astronomy meetings ever held, it saw a pot pourri of frontline astronomy topics being presented. The General Assembly resulted in the redefinition of the astronomical unit, and the meeting played an essential role in establishing a number of science- and technology-related collaborations throughout the world. The IAU also acquired a new divisional structure that fits better with the current astronomy landscape, focusing on education, outreach and development.

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Walls Of Lunar Crater May Hold Patchy Ice, LRO Radar Finds

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NASA’s Lunar Reconnaissance Orbiter has been studying the moon since June 2009. Credit: NASA

Small patches of ice could make up at most five to ten percent of material in walls of Shackleton crater.

Scientists using the Mini-RF radar on NASA’s Lunar Reconnaissance Orbiter (LRO) have estimated the maximum amount of ice likely to be found inside a permanently shadowed lunar crater located near the moon’s South Pole. As much as five to ten percent of material, by weight, could be patchy ice, according to the team of researchers led by Bradley Thomson at Boston University’s Center for Remote Sensing, in Mass.

“These terrific results from the Mini-RF team contribute to the evolving story of water on the moon,” says LRO’s deputy project scientist, John Keller of NASA’s Goddard Space Flight Center in Greenbelt, Md. “Several of the instruments on LRO have made unique contributions to this story, but only the radar penetrates beneath the surface to look for signatures of blocky ice deposits.”

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NASA’S SOFIA To Embark On New Cycle Of Science Observations

August 31, 2012 1 comment

Cabin View In Flight

The Stratospheric Observatory for Infrared Astronomy, or SOFIA, a joint program between NASA and the German Aerospace Center DLR, is set to begin its first full cycle of science flights starting in November 2012 and extending through December 2013. SOFIA’s Science Mission Operations Director Erick Young today announced the list of researchers who have been awarded time to study the universe with this unique infrared observatory.

SOFIA is a heavily modified 747SP aircraft that carries a telescope with an effective diameter of 100 inches (2.5 meters) to altitudes above 39,000 feet (12 km), beyond the obscuring layer of water vapor in Earth’s atmosphere.

In announcing the observing time awards, Young noted, “More than 1,000 hours of observing time were requested, five times the amount available, evidence of SOFIA’s desirability to astronomers. The approved projects make good use of the observatory’s capabilities to study objects ranging from Earth’s solar system neighbors to galaxies hundreds of millions of light years away.”

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Los Alamos Provides HOPE For Radiation Belt Storm Probes

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Los Alamos National Laboratory expertise in radiation detection and shielding is poised to help a national team of scientists better understand a mysterious region that can create hazardous space weather near our home planet.

The Helium Oxygen Proton Electron (HOPE) analyzer is one of a suite of instruments that was successfully launched today as part of the Radiation Belt Storm Probe mission—an effort by NASA and the Johns Hopkins University’s Applied Physics Laboratory to gain insight into the Sun’s influence on Earth and near-Earth space by studying our planet’s radiation belt.

“Today we are boldly going where no spacecraft ever wants to go,” said plasma physicist Geoffrey Reeves of Los Alamos National Laboratory’s Intelligence and Space Research Division. “We know we’re going into the riskiest of environments, so we’ve taken the greatest steps ensure the satellites can complete their mission.”

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NASA’s Dawn Prepares For Trek Toward Dwarf Planet

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This image of NASA’s Dawn spacecraft and the giant asteroid Vesta is an artist’s concept. Image credit: NASA/JPL-Caltech

NASA’s Dawn spacecraft is on track to become the first probe to orbit and study two distant solar system destinations, to help scientists answer questions about the formation of our solar system. The spacecraft is scheduled to leave the giant asteroid Vesta on Sept. 4 PDT (Sept. 5 EDT) to start its two-and-a-half-year journey to the dwarf planet Ceres.

Dawn began its 3-billion-mile (5-billion kilometer) odyssey to explore the two most massive objects in the main asteroid belt in 2007. Dawn arrived at Vesta in July 2011 and will reach Ceres in early 2015.

To make its escape from Vesta, the spacecraft will spiral away as gently as it arrived, using a special, hyper-efficient system called ion propulsion. Dawn’s ion propulsion system uses electricity to ionize xenon to generate thrust. The 12-inch-wide ion thrusters provide less power than conventional engines, but can maintain thrust for months at a time.

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