February 12, 2006, 7:57 PM CT

Most Ambitious Star Survey Ever

An international team of astronomers today announced the first results from the Radial Velocity Experiment, an ambitious all-sky spectroscopic survey aimed at measuring the speed, temperature, surface gravity and composition of up to a million stars passing near the sun. Those first results from the project, known for short as RAVE, confirm that dark matter dominates the total mass of our home galaxy, the Milky Way, team members at The Johns Hopkins University and elsewhere said. The full survey promises to yield a new, detailed understanding of the origins of the galaxy, they said.

The results were released at the American Astronomical Society's 207th meeting in Washington, D.C.

The team is using the "six-degree field" multi-object spectrograph on the 1.2-m UK Schmidt Telescope at the Anglo-Australian Observatory, located at Siding Spring Observatory in New South Wales, Australia. The instrument is capable of obtaining spectroscopic information for as a number of as 150 stars at once, said Rosemary Wyse, a professor in the Henry A. Rowland Department of Physics and Astronomy in Johns Hopkins' Krieger School of Arts and Sciences and a member of the RAVE team.........

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February 11, 2006, 1:53 PM CT

Giant Magellan Telescope

You would not want to play poker with Wendy Freedman. Even her children say so, she admits, and as she sits across the table on a summer morning in Tucson, Arizona, she gives no hint that she has just pushed almost all her chips into the middle of the table.

At this moment, about six miles away, a giant orange oven rotates, spinning up to its target speed of five revolutions per minute, on its way to its programmed temperature of about 2130 degrees Fahrenheit. By then, it will hold a lake of glass, 20 tons of borosilicate.

For another three days the oven will continue to spin, driving that lake of liquid glass into a parabola 330 inches across. Over the next several months, the glass will be slowly cooled and then polished exquisitely, to within.000001 of an inch of the theoretically perfect shape. Add an aluminum coating about 400 atoms thick, and there it will be: a telescope mirror, one of the largest in the world.........

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February 11, 2006, 12:39 AM CT

If Winter Olympic Games Were Held On The Moon

It's only a matter of time. One day, winter Olympics will be held on the moon. The moon's dust-covered slopes are good places to ski. There's plenty of powder, moguls and, best of all, low-gravity. With only 1/6th g holding them down, skiers and snowboarders can do tricks they only dreamed of doing on Earth. How about an octuple-twisting quadruple backflip? Don't worry. Crashes happen in slow-motion, so it won't hurt so much to wipe out.

And there's a perfect spot for the Olympic Village: the crater Plato. Most people don't know it, but Plato of ancient Greece was not only a philosopher, but also an Olympic champion. Twice he won the pankration competition-a grueling mix of boxing and wrestling. A crater named after Plato sounds like a good place for Olympic athletes to stay. The site is flat-bottomed, filled with raw materials for building stadia and habitats, and like Torino, Italy, the site of this year's games, Plato is near the Alps.

That is, the lunar Alps.

The lunar Alps are a range of mountains on the moon named after the Alps of Europe. They are similar to their Earthly counterparts in height, breath and spectacle. Since the modern Olympics began in 1896, most of the winter games have been held in the Alps. Why should the moon be different?........

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February 8, 2006, 10:41 PM CT

First Evidence of Cometary Ice

Comet Tempel 1, which created a flamboyant Fourth of July fireworks display in space last year, is covered with a small amount of water ice. These results, reported by members of NASA's Deep Impact team in an advanced online edition of Science, offer the first definitive evidence of surface ice on any comet.

"We have known for a long time that water ice exists in comets, but this is the first evidence of water ice on comets," said Jessica Sunshine, Deep Impact co-investigator and lead author of the Science article.

A chief scientist with Science Applications International Corporation who holds three Brown University degrees, Sunshine said the discovery offers important insight into the composition of comets - small, Sun-orbiting space travelers that are thought to beleftovers from the formation of the solar system.

"Understanding a comet's water cycle and supply is critical to understanding these bodies as a system and as a possible source that delivered water to Earth," she said. "Add the large organic component in comets and you have two of the key ingredients for life".

The findings help satisfy one of the major goals of the Deep Impact mission: Find out what is on the inside - and outside - of a comet.

To that end, NASA's Jet Propulsion Laboratory teamed with the University of Maryland to slam a space probe into Tempel 1, then analyze materials from the comet's surface and interior. On July 4, 2005, mission members hit their mark when the copper-tipped probe collided with Tempel 1 and created a spectacular extraterrestrial explosion 83 million miles from Earth.........

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February 7, 2006, 10:06 PM CT

Antarctic ice shelf retreats happened before

The retreat of Antarctic ice shelves is not new as per research published this week (24 Feb) in the journal Geology by researchers from Universities of Durham, Edinburgh and British Antarctic Survey (BAS).

A study of George VI Ice Shelf on the Antarctic Peninsula is the first to show that this currently 'healthy' ice shelf experienced an extensive retreat about 9500 years ago, more than anything seen in recent years. The retreat coincided with a shift in ocean currents that occurred after a long period of warmth. Whilst rising air temperatures are thought to bethe primary cause of recent dramatic disintegration of ice shelves like Larsen B, the new study suggests that the ocean may play a more significant role in destroying them than previously thought.

The University of Durham's, Dr Mike Bentley, one of the leaders of the project said,.

'We know that rising air temperatures can break up ice shelves but there has been a suspicion for some time that the role of the ocean may have been underestimated. This is some of the first evidence that a shift in ocean currents can actually destroy ice shelves. In this case it's possible that a preceding warm period may have primed the ice shelf to disintegrate when the ocean currents shifted.'

The researchers analysed sediments from the bottom of a freshwater lake close to the edge of the present George VI Ice Shelf. The results revealed that about 9500 years ago the ice shelf retreated, allowing the sea to flood into the lake. The ice shelf didn't reform until 1500 years later, and has been present ever since.........

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February 3, 2006, 0:09 AM CT

Icy Asteroid in Jupiter's Orbit

A bound pair of icy comets similar to the dirty snowballs circling outside the orbit of Neptune has been found lurking in the shadow of Jupiter.

Astronomers at the University of California, Berkeley, working with colleagues in France and at the Keck Telescope in Hawaii, have calculated the density of a known binary asteroid system that shares Jupiter's orbit, and concluded that Patroclus and its companion probably are composed mostly of water ice covered by a patina of dirt.

Because dirty snowballs are thought to have formed in the outer reaches of the solar system, from which they are occasionally dislodged and end up looping closer to the sun as comets, the team suggests that the asteroid probably formed far from the sun. It most likely was captured in one of Jupiter's Trojan points - two eddies where debris collects in Jupiter's orbit - during a period when the inner solar system was intensely bombarded by comets, around 650 million years after the formation of the solar system.

If confirmed, this could mean that a number of or most of the probably thousands of Jupiter's Trojan asteroids are dirty snowballs that originated much farther from the sun and at the same time as the objects now occupying the Kuiper Belt.

"It's our suspicion that the Trojans are small Kuiper Belt objects," said study leader Franck Marchis, a research astronomer at UC Berkeley.........

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February 2, 2006, 10:41 PM CT

The Big Bang

In physical cosmology, the Big Bang is the scientific theory that the Universe emerged from an enormously dense and hot state about 13.7 billion years ago. The Big Bang is a consequence of the observed Hubble's law velocities of distant galaxies that when taken together with the cosmological principle imply that space is expanding as per the Friedmann-Lemaître model of general relativity. Extrapolated into the past, these observations show that the Universe has expanded from a primeval state, in which all the matter and energy in the Universe was at an immense temperature and density. Physicists do not widely agree on what happened before this, eventhough general relativity predicts a gravitational singularity.

The term Big Bang is used both in a narrow sense to refer to a point in time when the observed expansion of the Universe (Hubble's law) began-calculated to be 13.7 billion (1.37 × 1010) years ago-and in a more general sense to refer to the prevailing cosmological paradigm explaining the origin and expansion of the Universe, as well as the composition of primordial matter through nucleosynthesis as predicted by the Alpher-Bethe-Gamow theory.

One consequence of the Big Bang is that the conditions of today's Universe are different from the conditions in the past or in the future. From this model, George Gamow in 1948 was able to predict, at least qualitatively, the existence of cosmic microwave background radiation (CMB). The CMB was discovered in the 1960s and further validated the Big Bang theory over its chief rival, the steady state theory.........

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January 25, 2006, 9:20 PM CT

Universe will end with a bang, or a whimper

While some pit science against faith, a Vatican astronomer contends that science is, in fact, a very Christian pursuit, but that it alone cannot answer all of life's big questions.

Guy Consolmagno of the Vatican Observatory visited the University of Alberta campus today to speak about the challenges of reconciling the scientific evidence that predicts a gloomy end to the universe with God's love of the world and the immortality of the soul.

Consolmagno explained the evidence for the Big Bang theory, which is generally accepted as the cause of the universe's creation, to a capacity crowd in the Education Building. The theory generally conceptualizes a universe that began, 10-20 billion years ago from a single point of extremely compressed matter and space that expanded outward. The theory also explains present scientific evidence of an expanding universe, which is being pushed apart by 'dark energy' at an ever-quickening pace.

"Not only does the Big Bang give us an idea of the beginning of the universe, but an ultimate fate," said Consolmagno.

It is hard to say precisely what the universe's end will look like, he added, but "either it will end with a bang, or it'll end with a whimper".

What's more, the Laws of Thermodynamics predict a sudden "heat death" of the universe, when all stars have died and an ever-expanding empty universe fills with expanding radiation.........

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January 18, 2006, 7:32 PM CT

Journey Continues

On January 14, 2004, President Bush put NASA on a new course into the cosmos. The Vision for Space Exploration announced that day focused the agency on a bold new mission: landing humans on the moon before the end of the next decade, paving the way for eventual journeys to Mars and beyond.

Two years later, we're well on our way to turning the Vision into reality. We've unveiled the plans for our next generation spacecraft, the Crew Exploration Vehicle, which builds on the best of Apollo and shuttle technology. We've returned the space shuttle fleet to flight and celebrated the fifth anniversary of continuous crew operations on the International Space Station.

Human and robotic explorers will work together to reach future destinations, and NASA spacecraft are already paving the way. Mars rovers Spirit and Opportunity are going strong two years after landing on what was to be a 90-day mission on the red planet. A new mission, the Mars Reconnaissance Orbiter arrives in March. The Cassini-Huygens mission is returning breathtaking images of Saturn and its moons, while space telescopes like Hubble, Spitzer and Chandra probe mysteries far beyond our own solar system.

On January 15, the Stardust spacecraft returns particles from a comet back to Earth. A similar mission, Deep Impact, slammed into a comet on Independence Day and recorded the impact. Later this month, NASA launches its latest planetary explorer, the New Horizons mission to Pluto.........

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January 16, 2006, 10:30 PM CT

Old Stars And Mysterious Cosmic Explosions

Cosmic gamma-ray bursts, the most powerful explosions in the universe, have the extreme brilliance of a billion billion Suns and occur several times a day. But they are not all created equal. For several decades astronomers have known that two types exist--long ones that last for tens or hundreds of seconds, and short bursts, which last a few milliseconds to a second. Intense research over the last decade has shown that long bursts are the death throes of massive stars in distant, young, and vigorously star forming galaxies. The origin of the short gamma-ray bursts, however, has been shrouded in mystery until now. Edo Berger, a Hubble post-doctoral fellow at the Carnegie Observatories, is lead author of the first study that accurately pinpoints a short gamma-ray burst to an old dead galaxy, implicating a population of old neutron stars as the sources of these explosions. The study appears in the December 15, 2005, issue of Nature.

"We had no idea if they explode in nearby galaxies, or the farthest reaches of the universe, or even what kind of object was producing them," stated Berger. "Now, after eluding us for years, we have finally found out what objects are giving rise to these explosions." he added.

Because short gamma-ray bursts are fainter than the long bursts, they have been very difficult to localize until recently, with the advent of NASA's Swift satellite and rapid follow-up by telescopes on the ground. Swift detects and observes gamma-ray bursts in multiple wavelengths and alerts astronomers who quickly point ground-based telescopes to catch the fading afterglow--the dying ember that glows for hours or days after the burst of gamma-rays.........

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