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Starless Cloud Cores Reveal Why Some Stars Are Bigger Than Others

December 20, 2013 Leave a comment

Credit: Bill Saxton & Alexandra Angelich (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO)

Credit: Bill Saxton & Alexandra Angelich (NRAO/AUI/NSF); ALMA (ESO/NAOJ/NRAO)

Massive stars – those at least 8 times the mass of our Sun – present an intriguing mystery: how do they grow so large when the vast majority of stars in the Milky Way are considerably smaller?

To find the answer, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to survey the cores of some of the darkest, coldest, and densest clouds in our Galaxy to search for the telltale signs of star formation.

To find the answer, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to survey the cores of some of the darkest, coldest, and densest clouds in our Galaxy to search for the telltale signs of star formation.

Since these cloud cores are so massive and dense, gravity should have already overwhelmed their supporting gas pressure, allowing them to collapse to form new, Sun-mass stars. If a star had not yet begun to shine, that would be a hint that something extra was supporting the cloud.

“A starless core would indicate that some force was balancing out the pull of gravity, regulating star formation, and allowing vast amounts of material to accumulate in a scaled-up version of the way our own Sun formed,” remarked Jonathan Tan, an astrophysicist at the University of Florida, Gainesville, and lead author of a paper published today in the Astrophysical Journal. “This suggests that massive stars and Sun-like stars follow a universal mechanism for star formation. The only difference is the size of their parent clouds.”

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Liftoff For Europe’s Billion-Star Surveyor

December 19, 2013 1 comment

Copyright ESA–S. Corvaja, 2013

Copyright ESA–S. Corvaja, 2013

19 December 2013 ESA PR 44-2013: ESA’s Gaia mission blasted off this morning on a Soyuz rocket from Europe’s Spaceport in Kourou, French Guiana, on its exciting mission to study a billion suns.

Gaia is destined to create the most accurate map yet of the Milky Way. By making accurate measurements of the positions and motions of 1% of the total population of roughly 100 billion stars, it will answer questions about the origin and evolution of our home Galaxy.

The Soyuz launcher, operated by Arianespace, lifted off at 09:12 GMT (10:12 CET). About ten minutes later, after separation of the first three stages, the Fregat upper stage ignited, delivering Gaia into a temporary parking orbit at an altitude of 175 km.

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Beatles Legend, Antiwar Author Among Those Honored By Newly Named Mercury Craters

December 19, 2013 Leave a comment

The International Astronomical Union (IAU) — the arbiter of planetary and satellite nomenclature since its inception in 1919 — recently approved a proposal from the MESSENGER Science Team to assign names to 10 impact craters on Mercury. In keeping with the established naming theme for craters on Mercury, all of the newly designated features are named after “deceased artists, musicians, painters, and authors who have made outstanding or fundamental contributions to their field and have been recognized as art historically significant figures for more than 50 years.”

Ten newly named craters join 114 other craters named since the MESSENGER spacecraft’s first Mercury flyby in January 2008. More information about the names of features on Mercury and the other objects in the Solar System can be found at the U.S. Geological Survey’s planetary nomenclature web site.

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NASA’s Asteroid Hunter Spacecraft Returns First Images After Reactivation

December 19, 2013 Leave a comment

Image credit: NASA/JPL-Caltech

Image credit: NASA/JPL-Caltech

NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE), a spacecraft that made the most comprehensive survey to date of asteroids and comets, has returned its first set of test images in preparation for a renewed mission.

NEOWISE discovered more than 34,000 asteroids and characterized 158,000 throughout the solar system during its prime mission in 2010 and early 2011. It was reactivated in September following 31 months in hibernation, to assist NASA’s efforts to identify the population of potentially hazardous near-Earth objects (NEOs). NEOWISE also can assist in characterizing previously detected asteroids that could be considered potential targets for future exploration missions.

“NEOWISE not only gives us a better understanding of the asteroids and comets we study directly, but it will help us refine our concepts and mission operation plans for future, space-based near-Earth object cataloging missions,” said Amy Mainzer, principal investigator for NEOWISE at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “The spacecraft is in excellent health, and the new images look just as good as they were before hibernation. Over the next weeks and months we will be gearing up our ground-based data processing and expect to get back into the asteroid hunting business, and acquire our first previously undiscovered space rock, in the next few months.”

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ESA’s Billion Star Surveyor: UCL’s Contribution

December 18, 2013 Leave a comment

On Thursday 19 December at 09:12 GMT, a satellite designed to unlock the secrets of the birth and evolution of the Milky Way Galaxy will be launched by the European Space Agency.

UCL’s Mullard Space Science Laboratory has played a major part in the satellite – named Gaia – for 12 years, developing the instrument that will measure the speed, temperature, size and age of over a billion stars in our galaxy.

Gaia’s mission is to slowly scan the sky, rotating every six hours, and survey the whole sky some hundred times in its six year mission. It has two extraordinarily stable telescopes, each focussing on the same huge array of 106 electronic detectors, the biggest ever either launched into orbit or on any Earth-based telescope.

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Was Einstein right? Scientists To Image Event Horizon Of Black Hole

December 18, 2013 Leave a comment

The European Research Council (ERC) has awarded 14 Million Euros to a team of European astrophysicists to construct the first accurate image of a black hole. The team will test the predictions of current theories of gravity, including Einstein’s theory of General Relativity, The funding is provided in the form of a Synergy Grant, the largest and most competitive type of grant of the ERC.

The team led by three principal investigators, Heino Falcke, Radboud University Nijmegen, Michael Kramer, Max-Planck-Institut für Radioastronomie, and Luciano Rezzolla, Goethe University in Frankfurt, hopes to measure the shadow cast by the event horizon of the black hole in the center of the Milky Way, find new radiopulsars near this black hole, and combine these measurements with advanced computer simulations of the behaviour of light and matter around black holes as predicted by theories of gravity. They will combine several telescopes around the globe to peer into the heart of our own Galaxy, which hosts a mysterious radio source, called Sagittarius A* and which is considered to be the central supermassive black hole.

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U-M Space Weather Model Picked To Improve US Warning System

December 18, 2013 Leave a comment

A University of Michigan space weather model beat out four other contenders for a spot in the national Space Weather Prediction Center’s forecasting toolbox.

It is the first time that computer models based on a firm understanding of physics have overtaken simpler, statistics-based models to predict magnetic disturbances due to space weather. The new model can also give information about where the effects of a geomagnetic storm will be weaker or stronger around Earth.

Space weather forecasts are important for protecting satellites, predicting when GPS signals become unreliable, and in the worst case, preventing far-reaching and long-term electrical power outages.

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