December 5, 2006, 8:51 PM CT

Astronomers Study Shape Of Stellar Candles

Astronomers are reporting remarkable new findings that shed light on a decade-long debate about one kind of supernovae, the explosions that mark a star's final demise: does the star die in a slow burn or with a fast bang" From their observations, the researchers find that the matter ejected by the explosion shows significant peripheral asymmetry but a nearly spherical interior, most likely implying that the explosion finally propagates at supersonic speed.

These results are reported today in Science Express, the online version of the research journal Science, by Lifan Wang, Texas A&M University (USA), and his colleagues Dietrich Baade and Ferdinando Patat from ESO.

"Our results strongly suggest a two-stage explosion process in this type of supernova," comments Wang. "This is an important finding with potential implications in cosmology".

Using observations of 17 supernovae made over more than 10 years with ESO's Very Large Telescope and the McDonald Observatory's Otto Struve Telescope, astronomers inferred the shape and structure of the debris cloud thrown out from Type Ia supernovae. Such supernovae are believed to be the result of the explosion of a small and dense star - a white dwarf - inside a binary system. As its companion continuously spills matter onto the white dwarf, the white dwarf reaches a critical mass, leading to a fatal instability and the supernova. But what sparks the initial explosion, and how the blast travels through the star have long been thorny issues.........

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November 28, 2006, 8:19 PM CT

First ever Gamma Ray Clock

Astronomers using the H.E.S.S. telescopes have discovered the first ever modulated signal from space in Very High Energy Gamma Rays - the most energetic such signal ever observed. Regular signals from space have been known since the 1960s, when the first radio pulsar (nicknamed Little Green Men-1 for its regular nature) was discovered. This is the first time a signal has been seen at such high energies - 100,000 times higher than previously known - and is reported today (24th November) in the Journal Astronomy and Astrophysics.

The signal comes from a system called LS 5039 which was discovered by the H.E.S.S. team in 2005. LS5039 is a binary system formed of a massive blue star (20 times the mass of the Sun) and an unknown object, possibly a black hole. The two objects orbit each other at very short distance, varying between only 1/5 and 2/5 of the separation of the Earth from the Sun, with one orbit completed every four days.

"The way in which the gamma ray signal varies makes LS5039 a unique laboratory for studying particle acceleration near compact objects such as black holes." Explained Dr Paula Chadwick from the University of Durham, a British team member of H.E.S.S.

Different mechanisms can affect the gamma-ray signal that reaches Earth and by seeing how the signal varies, astronomers can learn a great deal about binary systems such as LS 5039 and also the effects that take place near black holes.........

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November 20, 2006, 8:32 PM CT

Fascinating Twin Star Explosions

Researchers using NASA's Swift satellite stumbled upon a rare sight, two supernovas side by side in one galaxy. Large galaxies typically play host to three supernovaccording to century. Galaxy NGC 1316 has had two supernovas in less than five months, and a total of four supernova in 26 years, as far back as the records go. This makes NGC 1316 the most prodigious known producer of supernovas.

The first supernova, still visible on the "right" in the image, was detected on June 19, 2006, and was named SN 2006dd. The second supernova, on the immediate "left" in the image, was detected on November 5 and has been named SN 2006mr. (The central bright spot is the galaxy core, and the bright object to the far left, like an earring, is a foreground star.).

NGC 1316, a massive elliptical galaxy about 80 million light years way, has recently merged with a spiral galaxy. Mergers do indeed spawn supernovas by forcing the creation of new, massive stars, which quickly die and explode. Yet all four supernovas in NGC 1316 appear to be Type Ia, a variety previously not linked to galaxy mergers and massive star formation. Researchers are intrigued and are investigating whether the high supernova rate is a coincidence or a result of the merger. Swift was launched on this date, November 20, in 2004.........

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November 16, 2006, 8:45 PM CT

Origin Of Appalachian Mountains

Geologists have developed a new theory to explain how and when the Appalachian Mountain range was created. Their research redraws the map of the planet from 420 million years ago.

The researchers recently discovered a piece of the Appalachian Mountains in southern Mexico, a location geologists long had assumed was part of the North American Cordillera. The Cordillera is a continuous sequence of mountain ranges that includes the Rocky Mountains. It stretches from Alaska to Mexico and continues into South America.

For the past decade, geologists have collected information from Mexico's Acatlán Complex, a rock outcropping the size of Massachusetts. As they uncovered each new piece of data from the complex, evidence contradicting earlier assumptions about the origins of that part of Mexico emerged.

"It was a story that had the Appalachians written all over it," said Damian Nance, Ohio University professor of geological sciences and lead author of an article detailing the findings, which was reported in the recent issue of Geology. "This will change the way geologists look at Mexico".

It also changes existing theory regarding the creation of the Appalachians, which has radically altered scientists' understanding of the planet's geography, said Nance. Age data, newly unearthed fossils and chemical analysis of the rocks show that the complex is much younger than previously thought. It records a pivotal part of the Appalachian story not preserved elsewhere.........

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November 16, 2006, 4:35 AM CT

Relativistic Pinball Machine

New clues about the origins of cosmic rays, mysterious high-energy particles that bombard the Earth, have been revealed using NASA's Chandra X-ray Observatory. An extraordinarily detailed image of the remains of an exploded star provides crucial insight into the generation of cosmic rays.

For the first time, astronomers have mapped the rate of acceleration of cosmic ray electrons in a supernova remnant. The new map shows that the electrons are being accelerated at close to the theoretically maximum rate. This discovery provides compelling evidence that supernova remnants are key sites for energizing charged particles.

The map was created from an image of Cassiopeia A, a 325-year-old remnant produced by the explosive death of a massive star. The blue, wispy arcs in the image trace the expanding outer shock wave where the acceleration takes place. The other colors in the image show debris from the explosion that has been heated to millions of degrees.

"Scientists have theorized since the 1960s that cosmic rays must be created in the tangle of magnetic fields at the shock, but here we can see this happening directly," said Michael Stage of the University of Massachusetts, Amherst. "Explaining where cosmic rays come from helps us to understand other mysterious phenomena in the high-energy universe".........

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November 10, 2006, 4:52 AM CT

Eye Of A Monster Storm On Saturn

NASA's Cassini spacecraft has seen something never before seen on another planet -- a hurricane-like storm at Saturn's south pole with a well-developed eye, ringed by towering clouds.

The "hurricane" spans a dark area inside a thick, brighter ring of clouds. It is approximately 8,000 kilometers (5,000 miles) across, or two thirds the diameter of Earth.

"It looks like a hurricane, but it doesn't behave like a hurricane," said Dr. Andrew Ingersoll, a member of Cassini's imaging team at the California Institute of Technology, Pasadena. "Whatever it is, we're going to focus on the eye of this storm and find out why it's there".

A movie taken by Cassini's camera over a three-hour period reveals winds around Saturn's south pole blowing clockwise at 550 kilometers (350 miles) per hour. The camera also saw the shadow cast by a ring of towering clouds surrounding the pole, and two spiral arms of clouds extending from the central ring. These ring clouds, 30 to 75 kilometers (20 to 45 miles) above those in the center of the storm, are two to five times taller than the clouds of thunderstorms and hurricanes on Earth.

Eye-wall clouds are a distinguishing feature of hurricanes on Earth. They form where moist air flows inward across the ocean's surface, rising vertically and releasing a heavy rain around an interior circle of descending air that is the eye of the storm itself. Though it is uncertain whether such moist convection is driving Saturn's storm, the dark "eye" at the pole, the eye-wall clouds and the spiral arms together indicate a hurricane-like system.........

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November 6, 2006, 9:10 PM CT

Could You Explain The Origins Of The Universe?

Formative Evaluation of the Large Hadron Collider Communications Project.

PPARC has commissioned research that asked adults, teachers and young people about their interest in, knowledge of and concerns about the Large Hadron Collider (LHC) project. Due to start in late 2007, at CERN, Geneva, it will be one of the largest experiments in the history of science, and will investigate the Origin of the Universe.

Dr Ray Mathias (UK LHC Communications Manager) said "The research, which used focus groups and in-depth interviews, revealed a lot of interest, particularly through links to the Big Bang, spin-offs to the healthcare sector, and human-interest stories, especially those involving British researchers and engineers. These findings will guide how we invest in different outreach activities. The UK is contributing over 300M to the LHC, and we have a responsibility to engage the public in understanding and debating the excitement, implications and costs of the project".........

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November 1, 2006, 8:37 PM CT

Mercury to Transit the Sun

On Nov. 8, 2006, Mercury will pass directly between the sun and the Earth, a transit that will cause the tiny, innermost planet to appear as a small black shadow moving across the bright solar disk.

A special event at Kitt Peak National Observatory near Tucson, Ariz., will offer the public a unique opportunity to view the transit, which is invisible to the naked eye, in real-time through the observatory's specially filtered, 16-inch, public-outreach telescope.

From moments before the transit begins at 2:12 p.m. Eastern time, through its conclusion 5 hours later, anyone with access to the Internet will see the small planet's shadow slowly pass across the sun. A media team from the National Science Foundation-supported Exploratorium in San Francisco will webcast the live event.

Kitt Peak is part of the National Science Foundation (NSF) National Optical Astronomy Observatory.

To watch the event, go to: www.exploratorium.edu/transit.

At the top of every hour, commentary and interviews with Kitt Peak astronomers will provide context to the celestial event. Andrew Potter of NSF's National Solar Observatory (NSO) will share how the world's largest solar telescope--Kitt Peak's McMath-Pierce Solar Telescope--is allowing him to make special observations of Mercury's thin atmosphere against the backdrop of the sun and its known spectral signature.........

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November 1, 2006, 8:13 PM CT

First Sunrise on Hinode's instruments

The Hinode (formerly Solar-B) satellite, a joint Japan/NASA/PPARC mission launched on 22nd September 2006, reported its first observations of the Sun with its suite of scientific instruments on 31st October 2006.

The satellite was renamed 'Hinode' which is Japanese for Sunrise, which is most appropriate since Hinode will watch at close hand massively explosive solar flares erupting from the Sun's surface and rising into interstellar space.

High resolution image of the Sun taken by the X-ray Telescope on Hinode.

Credit: JAXAHinode has three instruments: the Solar Optical Telescope (SOT), the X-Ray Telescope (XRT), and the EUV Imaging Spectrometer (EIS) which has been led by University College London's Mullard Space Science Laboratory (MSSL).

"Waiting for the first data from an instrument that has taken years to design and build is always a heart-stopping moment," said Prof Len Culhane, EIS Principal Investigator, "We create incredibly sensitive detectors such as EIS, then strap them to a rocket and hurl them into space under extremely challenging conditions. Finding out that it survived and is working correctly is a huge relief because the options are very limited if it is not".

Image showing convection cells that are the locations of concentration of the magnetic field.........

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October 31, 2006, 6:53 PM CT

Snake on a Galactic Plane!

Something scary appears to be slithering across the plane of our Milky Way galaxy in this new Halloween image from NASA's Spitzer Space Telescope. The snake-like object is actually the core of a thick, sooty cloud large enough to swallow dozens of solar systems. In fact, astronomers say its "belly" may be harboring beastly stars in the process of forming.

"The snake is an ideal place to hunt for massive forming stars as they have not had time to heat up and destroy the cloud they are born in," said Dr. Sean Carey, also known as "Dr. Scarey," of NASA's Spitzer Science Center. Dr. Scarey, who is leading the new research, was also principal investigator of a prior Halloween image from Spitzer, showing a 'great galactic ghoul'.

Spitzer was able to spot the sinuous cloud using its heat-seeking infrared vision. The object is hiding in the dusty plane of our Milky Way galaxy, invisible to optical telescopes. Because its heat, or infrared light, can sneak through the dust, it first showed up in infrared images from past missions. The cloud is so thick with dust that if you were to somehow transport yourself into the middle of it, you would see nothing but black, not even a star in the sky. Now, that's spooky!.

Spitzer's new view of the snake provides the best look at what lurks inside. The yellow and orange spots located on and around it are massive stars just beginning to take shape. The bright red spot located on its belly is a monstrous stellar embryo, with about 20 to 50 times the mass of our sun.........

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