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domenica 28 giugno 2009

Mars Rover Yielding New Clues While Lodged In Martian Soil

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ScienceDaily (June 28, 2009) — NASA's Mars rover Spirit, lodged in Martian soil that is causing traction trouble, is taking advantage of the situation by learning more about the Red Planet's environmental history.
In April, Spirit entered an area composed of three or more layers of soil with differing pastel hues hiding beneath a darker sand blanket. Scientists dubbed the site "Troy." Spirit's rotating wheels dug themselves more than hub deep at the site. The rover team has spent weeks studying Spirit's situation and preparing a simulation of this Martian driving dilemma to test escape maneuvers using an engineering test rover at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
A rock seen beneath Spirit in images from the camera on the end of the rover's arm may be touching Spirit's belly. Scientists believe it appears to be a loose rock not bearing the rover's weight. While Spirit awaits extraction instructions, the rover is keeping busy examining Troy, which is next to a low plateau called Home Plate, approximately 3.2 kilometers (2 miles) southeast of where Spirit landed in January 2004.
"By serendipity, Troy is one of the most interesting places Spirit has been," said Ray Arvidson of Washington University in St. Louis. Arvidson is deputy principal investigator for the science payloads on Spirit and its twin rover, Opportunity. "We are able here to study each layer, each different color of the interesting soils exposed by the wheels."
One of the rover's wheels tore into the site, exposing colored sandy materials and a miniature cliff of cemented sands. Some disturbed material cascaded down, evidence of the looseness that will be a challenge for getting Spirit out. But at the edge of the disturbed patch, the soil is cohesive enough to hold its shape as a steep cross-section.
Spirit has been using tools on its robotic arm to examine tan, yellow, white and dark-red sandy soil at Troy. Stretched-color images from the panoramic camera show the tints best.
"The layers have basaltic sand, sulfate-rich sand and areas with the addition of silica-rich materials, possibly sorted by wind and cemented by the action of thin films of water. We're still at a stage of multiple working hypotheses," said Arvidson. "This may be evidence of much more recent processes than the formation of Home Plate...or is Home Plate being slowly stripped back by wind, and we happened to stir up a deposit from billions of years ago before the wind got to it?"
Team members from NASA's Johnson Space Center in Houston feel initial readings suggest that iron is mostly present in an oxidized form as ferric sulfate and that some of the differences in tints at Troy observed by the panoramic camera may come from differences in the hydration states of iron sulfates.
While extraction plans for the rover are developed and tested during the coming weeks, the team plans to have Spirit further analyze the soil from different depths. This research benefits from having time and power. In April and May, winds blew away most of the dust that had accumulated on Spirit's solar panels.
"The exceptional amount of power available from cleaning of Spirit's solar arrays by the wind enables full use of all of the rover's science instruments," said Richard Moddis of the Johnson team. "If your rover is going to get bogged down, it's nice to have it be at a location so scientifically interesting."
The rover team has developed a soil mix for testing purposes that has physical properties similar to those of the soil under Spirit at Troy. This soil recipe combines diatomaceous earth, powdered clay and play sand. A crew is shaping a few tons of that mix this week into contours matching Troy's. The test rover will be commanded through various combinations of maneuvers during the next few weeks to validate the safest way to proceed on Mars.
Spirit's right-front wheel has been immobile for more than three years, magnifying the challenge. While acknowledging a possibility that Spirit might not be able to leave Troy, the rover team remains optimistic. Diagnostic tests on Spirit in early June provided encouragement that the left-middle wheel remains useable despite an earlier stall.
"With the improved power situation, we have the time to explore all the possibilities to get Spirit out," said JPL's John Callas, project manager for Spirit and Opportunity. "We are optimistic. The last time Spirit spun its wheels, it was still making progress. The ground testing will help us avoid doing things that could make Spirit's situation worse."
Images and further information about Spirit and Opportunity are available at: http://marsrovers.jpl.nasa.gov and http://www.nasa.gov/rovers .
Adapted from materials provided by NASA/Jet Propulsion Laboratory.

venerdì 19 giugno 2009

Mystery Of The Missing Sunspots Solved?

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ScienceDaily (June 19, 2009) — The sun is in the pits of a century-class solar minimum, and sunspots have been puzzlingly scarce for more than two years. Now, for the first time, solar physicists might understand why.
At an American Astronomical Society press conference in Boulder, Colorado, researchers announced that a jet stream deep inside the sun is migrating slower than usual through the star's interior, giving rise to the current lack of sunspots.
Rachel Howe and Frank Hill of the National Solar Observatory (NSO) in Tucson, Arizona, used a technique called helioseismology to detect and track the jet stream down to depths of 7,000 km below the surface of the sun. The sun generates new jet streams near its poles every 11 years, they explained. The streams migrate slowly from the poles to the equator and when a jet stream reaches the critical latitude of 22 degrees, new-cycle sunspots begin to appear.
Howe and Hill found that the stream associated with the next solar cycle has moved sluggishly, taking three years to cover a 10 degree range in latitude compared to only two years for the previous solar cycle.
The jet stream is now, finally, reaching the critical latitude, heralding a return of solar activity in the months and years ahead.
"It is exciting to see", says Hill, "that just as this sluggish stream reaches the usual active latitude of 22 degrees, a year late, we finally begin to see new groups of sunspots emerging."
The current solar minimum has been so long and deep, it prompted some scientists to speculate that the sun might enter a long period with no sunspot activity at all, akin to the Maunder Minimum of the 17th century. This new result dispells those concerns. The sun's internal magnetic dynamo is still operating, and the sunspot cycle is not "broken."
Because it flows beneath the surface of the sun, the jet stream is not directly visible. Hill and Howe tracked its hidden motions via helioseismology. Shifting masses inside the sun send pressure waves rippling through the stellar interior. So-called "p modes" (p for pressure) bounce around the interior and cause the sun to ring like an enormous bell. By studying the vibrations of the sun's surface, it is possible to figure out what is happening inside. Similar techniques are used by geologists to map the interior of our planet.
In this case, researchers combined data from GONG and SOHO. GONG, short for "Global Oscillation Network Group," is an NSO-led network of telescopes that measures solar vibrations from various locations around Earth. SOHO, the Solar and Heliospheric Observatory, makes similar measurements from space.
"This is an important discovery," says Dean Pesnell of NASA's Goddard Space Flight Center. "It shows how flows inside the sun are tied to the creation of sunspots and how jet streams can affect the timing of the solar cycle."
There is, however, much more to learn.
"We still don't understand exactly how jet streams trigger sunspot production," says Pesnell. "Nor do we fully understand how the jet streams themselves are generated."
To solve these mysteries, and others, NASA plans to launch the Solar Dynamics Observatory (SDO) later this year. SDO is equipped with sophisticated helioseismology sensors that will allow it to probe the solar interior better than ever before.
"The Helioseismic and Magnetic Imager (HMI) on SDO will improve our understanding of these jet streams and other internal flows by providing full disk images at ever-increasing depths in the sun," says Pesnell.
Continued tracking and study of solar jet streams could help researchers do something unprecedented--accurately predict the unfolding of future solar cycles.
Adapted from materials provided by http://science.nasa.gov/. Original article written by Dr. Tony Phillips.

Definitive Evidence For Ancient Lake On Mars

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ScienceDaily (June 18, 2009) — A University of Colorado at Boulder research team has discovered the first definitive evidence of shorelines on Mars, an indication of a deep, ancient lake there and a finding with implications for the discovery of past life on the Red Planet.
Estimated to be more than 3 billion years old, the lake appears to have covered as much as 80 square miles and was up to 1,500 feet deep -- roughly the equivalent of Lake Champlain bordering the United States and Canada, said CU-Boulder Research Associate Gaetano Di Achille, who led the study. The shoreline evidence, found along a broad delta, included a series of alternating ridges and troughs thought to be surviving remnants of beach deposits.
"This is the first unambiguous evidence of shorelines on the surface of Mars," said Di Achille. "The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."
A paper on the subject by Di Achille, CU-Boulder Assistant Professor Brian Hynek and CU-Boulder Research Associate Mindi Searls, all of the Laboratory for Atmospheric and Space Physics, has been published online in Geophysical Research Letters, a publication of the American Geophysical Union.
Images used for the study were taken by a high-powered camera known as the High Resolution Imaging Science Experiment, or HiRISE. Riding on NASA's Mars Reconnaissance Orbiter, HiRISE can resolve features on the surface down to one meter in size from its orbit 200 miles above Mars.
An analysis of the HiRISE images indicate that water carved a 30-mile-long canyon that opened up into a valley, depositing sediment that formed a large delta. This delta and others surrounding the basin imply the existence of a large, long-lived lake, said Hynek, also an assistant professor in CU-Boulder's geological sciences department. The lake bed is located within a much larger valley known as the Shalbatana Vallis.
"Finding shorelines is a Holy Grail of sorts to us," said Hynek.
In addition, the evidence shows the lake existed during a time when Mars is generally believed to have been cold and dry, which is at odds with current theories proposed by many planetary scientists, he said. "Not only does this research prove there was a long-lived lake system on Mars, but we can see that the lake formed after the warm, wet period is thought to have dissipated."
Planetary scientists think the oldest surfaces on Mars formed during the wet and warm Noachan epoch from about 4.1 billion to 3.7 billion years ago that featured a bombardment of large meteors and extensive flooding. The newly discovered lake is believed to have formed during the Hesperian epoch and postdates the end of the warm and wet period on Mars by 300 million years, according to the study.
The deltas adjacent to the lake are of high interest to planetary scientists because deltas on Earth rapidly bury organic carbon and other biomarkers of life, according to Hynek. Most astrobiologists believe any present indications of life on Mars will be discovered in the form of subterranean microorganisms.
But in the past, lakes on Mars would have provided cozy surface habitats rich in nutrients for such microbes, Hynek said.
The retreat of the lake apparently was rapid enough to prevent the formation of additional, lower shorelines, said Di Achille. The lake probably either evaporated or froze over with the ice slowly turning to water vapor and disappearing during a period of abrupt climate change, according to the study.
Di Achille said the newly discovered pristine lake bed and delta deposits would be would be a prime target for a future landing mission to Mars in search of evidence of past life.
"On Earth, deltas and lakes are excellent collectors and preservers of signs of past life," said Di Achille. "If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past."
Adapted from materials provided by University of Colorado at Boulder.

Lunar Reconnaissance Orbiter: NASA Returns To The Moon With First Lunar Launch In A Decade

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ScienceDaily (June 19, 2009) — NASA's Lunar Reconnaissance Orbiter launched at 5:32 p.m. EDT Thursday aboard an Atlas V rocket from Cape Canaveral Air Force Station in Florida. The satellite will relay more information about the lunar environment than any other previous mission to the moon.
The orbiter, known as LRO, separated from the Atlas V rocket carrying it and a companion mission, the Lunar Crater Observation and Sensing Satellite, or LCROSS, and immediately began powering up the components necessary to control the spacecraft. The flight operations team established communication with LRO and commanded the successful deployment of the solar array at 7:40 p.m. The operations team continues to check out the spacecraft subsystems and prepare for the first mid-course correction maneuver. NASA scientists expect to establish communications with LCROSS about four hours after launch, at approximately 9:30 p.m.
"This is a very important day for NASA," said Doug Cooke, associate administrator for NASA's Exploration Systems Mission Directorate in Washington, which designed and developed both the LRO and LCROSS missions. "We look forward to an extraordinary period of discovery at the moon and the information LRO will give us for future exploration missions."
The spacecraft will be placed in low polar orbit about 31 miles, or 50 kilometers, above the moon for a one year primary mission. LRO's instruments will help scientists compile high resolution three-dimensional maps of the lunar surface and also survey it at many spectral wavelengths. The satellite will explore the moon's deepest craters, exploring permanently sunlit and shadowed regions, and provide understanding of the effects of lunar radiation on humans.
"Our job is to perform reconnaissance of the moon's surface using a suite of seven powerful instruments," said Craig Tooley, LRO project manager at NASA's Goddard Space Flight Center in Greenbelt, Md. "NASA will use the data LRO collects to design the vehicles and systems for returning humans to the moon and selecting the landing sites that will be their destinations."
High resolution imagery from LRO's camera will help identify landing sites for future explorers and characterize the moon's topography and composition. The hydrogen concentrations at the moon's poles will be mapped in detail, pinpointing the locations of possible water ice. A miniaturized radar system will image the poles and test communication capabilities.
"During the 60 day commissioning period, we will turn on spacecraft components and science instruments," explained Cathy Peddie, LRO deputy project manager at Goddard. "All instruments will be turned on within two weeks of launch, and we should start seeing the moon in new and greater detail within the next month."
"We learned much about the moon from the Apollo program, but now it is time to return to the moon for intensive study, and we will do just that with LRO," said Richard Vondrak, LRO project scientist at Goddard.
All LRO initial data sets will be deposited in the Planetary Data System, a publicly accessible repository of planetary science information, within six months of launch.
Goddard built and manages LRO. LRO is a NASA mission with international participation from the Institute for Space Research in Moscow. Russia provides the neutron detector aboard the spacecraft.
The LRO mission is providing updates via @LRO_NASA on Twitter. To follow, visit:
http://www.twitter.com/lro_nasa
For more information about the LRO mission, visit:
http://www.nasa.gov/lro
Adapted from materials provided by NASA.

venerdì 12 giugno 2009

Baby Stars Finally Found In Jumbled Galactic Center


ScienceDaily (June 12, 2009) — Astronomers have at last uncovered newborn stars at the frenzied center of our Milky Way galaxy. The discovery was made using the infrared vision of NASA's Spitzer Space Telescope.
The heart of our spiral galaxy is cluttered with stars, dust and gas, and at its very center, a supermassive black hole. Conditions there are harsh, with fierce stellar winds, powerful shock waves and other factors that make it difficult for stars to form. Astronomers have known that stars can form in this chaotic place, but they're baffled as to how this occurs. Confounding the problem is all the dust standing between us and the center of our galaxy. Until now, nobody had been able to definitively locate any baby stars.
"These stars are like needles in a haystack," said Solange Ramirez, the principal investigator of the research program at NASA's Exoplanet Science Institute at the California Institute of Technology, Pasadena. "There's no way to find them using optical light, because dust gets in the way. We needed Spitzer's infrared instruments to cut through the dust and narrow in on the objects."
The team plans to look for additional baby stars in the future, and ultimately to piece together what types of conditions allow stars to form in such an inhospitable environment as our galaxy's core.
"By studying individual stars in the galactic center, we can better understand how stars are formed in different interstellar environments," said Deokkeun An of the Infrared Processing and Analysis Center at Caltech, lead author of a paper submitted for publication in the Astrophysical Journal. "The Milky Way galaxy is just one of more than hundreds of billions of galaxies in the visible universe. However, our galaxy is so special because we can take a closer look at its individual stellar components." An started working on this program while a graduate student at Ohio State University, Columbus, under the leadership of Ohio State astronomer Kris Sellgren, the co-investigator on the project.
The core of the Milky Way is a mysterious place about 600 light-years across (light would take 600 years to travel from one end to the other). While this is just a fraction of the size of the entire Milky Way, which is about 100,000 light-years across, the core is stuffed with 10 percent of all the gas in the galaxy -- and loads and loads of stars.
Before now, there were only a few clues that stars can form in the galaxy's core. Astronomers had found clusters of massive adolescent stars, in addition to clouds of charged gas -- a sign that new stars are beginning to ignite and ionize surrounding gas. Past attempts had been unsuccessful in finding newborn stars, or as astronomers call them, young stellar objects.
Ramirez and colleagues began their search by scanning large Spitzer mosaics of our galactic center. They narrowed in on more than 100 candidates, but needed more detailed data to confirm the stars' identities. Young stellar objects, when viewed from far away, can look a lot like much older stars. Both types of stars are very dusty, and the dust lying between us and them obscures the view even further.
To sort through the confusion, the astronomers looked at their candidate stars with Spitzer's spectrograph – an instrument that breaks light apart to reveal its rainbow-like array of infrared colors. Molecules around stars leave imprints in their light, which the spectrograph can detect.
The results revealed three stars with clear signs of youth, for example, certain warm, dense gases. These youthful features are found in other places in the galaxy where stars are being formed.
"It is amazing to me that we have found these stars," said Ramirez. "The galactic center is a very interesting place. It has young stars, old stars, black holes, everything. We started mining a catalog of about 1 million sources and managed to find three young stars -- stars that will help reveal the secrets at the core of the Milky Way."
The young stellar objects are all less than about 1 million years old. They are embedded in cocoons of gas and dust, which will eventually flatten to disks that, according to theory, later lump together to form planets.
Other collaborators include Richard Arendt of NASA's Goddard Space Flight Center, Greenbelt, Md.; A. C. Adwin Boogert of NASA's Herschel Science Center, Caltech in Pasadena; Mathias Schultheis of the Besancon Observatory in France; Susan Stolovy of NASA's Spitzer Science Center, Caltech in Pasadena; Angela Cotera of SETI Institute, Mountain View, Calif.; and Thomas Robitaille and Howard Smith of Harvard Smithsonian Center for Astrophysics, Cambridge, Mass.
Adapted from materials provided by NASA/Jet Propulsion Laboratory.

mercoledì 17 ottobre 2007

Mars Express: Hummocky And Shallow Maunder Crater


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Science Daily — The High Resolution Stereo Camera (HRSC) on ESA’s Mars Express orbiter has obtained pictures of the Noachis Terra region on Mars, in particular, the striking Maunder crater.
Maunder crater lies at 50° South and 2° East, approximately in the center of Noachis Terra.
The impact crater, named after the british astronomer Edward W. Maunder (1851-1928), is located halfway between Argyre Planitia and Hellas Planitia on the southern Highlands of Mars.
With a diameter of 90 kilometres and a depth of barely 900 metres, the crater is not one of the largest impact craters on Mars at present, but it used to be much deeper. It has since been filled partially with large amounts of material.
The west of the crater experienced a major slope failure, during which a large landslide transported loose material eastward, to the inner parts of the crater. The edges of the crater rim that collapsed exhibit gullies which might be associated with the mass transport of the material.
The transition zone from the western rim of the crater to the rather smooth crater floor on the eastern edge shows hummocky terrain. Such terrain exhibits small, irregularly-shaped hills and valleys. The hummocky terrain in the Maunder crater was formed by deposition of landslide debris.
In the east, the crater floor is bounded by a trough, approximately 700 metres deep. The trough may be associated with a landslide on the western edge of the crater. Some gullies can be seen on the upper edge of the trough which is possible evidence for water seepage.
The small, 500 to 2500-metre long, dark features on the crater floor are eye-catching. These features are called Barchan dunes, one of the most abundant dune forms in arid environments. Dunes of this kind are also found on Earth, for example in the West-African Namib desert.
The colour scenes have been derived from the three HRSC-colour channels and the nadir channels. The perspective views have been calculated from the digital terrain model derived from the HRSC stereo channels. The anaglyph image was calculated from the nadir channels and two stereo channels, stereoscopic glasses are required for viewing. The 3-D (anaglyph) picture has been put together from several individual 3-D images of different scenes, enhancing the view over larger areas.
Note: This story has been adapted from material provided by European Space Agency.

Fausto Intilla

lunedì 15 ottobre 2007

Long-lost, Dangerous Asteroid Is Found Again


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Science Daily — Echoing the re-discovery of America by the Spanish long after an earlier Viking reconnaissance, astronomers have learned that a recently observed asteroid - one that could potentially hit the Earth - was actually first observed nearly a half-century ago. Researchers at the Minor Planet Center of the Smithsonian Astrophysical Observatory in Cambridge, MA have confirmed work by SETI Institute astronomer Peter Jenniskens that the recently discovered asteroid 2007 RR9 is in fact the long-lost object 6344 P-L.
6344 P-L was last seen in 1960, and ever since has had the peculiar distinction of being the only Potentially Hazardous Asteroid without a formal designation. "The object was long recognized to be dangerous, but we didn't know where it was," says Jenniskens. "Now it is no longer just out there."
A designation as Potentially Hazardous means that 2007 RR9 is one of 886 (not 887) known asteroids bigger than 150 m (500 ft) in diameter that come to within 0.05 astronomical units of Earth's orbit (roughly 7,480,000 km or 4,650,000 miles). The size is estimated on the basis of the object's observed brightness and an assumed reflectance of 13 percent.
Jenniskens believes that this object may not, in fact, be an asteroid. "This is a now-dormant comet nucleus, a fragment of a bigger object that, after breaking up in the not-so-distant past, may have caused the gamma Piscid shower of slow meteors (IAU #236) that is active in mid-October and early November," he says. 2007 RR9 moves in a 4.70-year orbit, nearly all the way out to the distance of Jupiter. Because of this elongated orbit, it has a Tisserand parameter of T = 2.94, which defines it dynamically as a Jupiter Family Comet (T = 2.0 - 3.0), not an asteroid (T > 3.0).
So far, this object has not yet been seen to be even weakly active, but the now dormant comet is still moving closer to the Sun. It is sliding rapidly toward visibility in the southern hemisphere, and is expected to brighten to magnitude +18.5 in mid-October. According to Gareth V. Williams of the Minor Planet Center, it will pass Earth around November 6 at 0.07 AU, when the minor planet is at high latitudes in southern skies.
The original designation of P-L stands for "Palomar-Leiden," the juxtaposition of two observatory names that reflect what was a very fruitful collaboration by the trio of pioneer asteroid searchers Tom Gehrels of the University of Arizona, and Ingrid van Houten-Groeneveld and her husband Cornelis Johannes van Houten. Gehrels made a sky survey using the 48-inch Schmidt Telescope at the famed Palomar Observatory, long before modern asteroid reconnaisances, and shipped the photographic plates to the van Houtens at Leiden Observatory in the Netherlands. There, Ingrid discovered 6344 P-L on four plates taken on September 24-28, 1960. The trio are jointly credited with several thousand asteroid discoveries, but only 6344 P-L is a potential danger to Earth.
Peter Jenniskens is a meteor astronomer with the SETI Institute and author of "Meteor Showers and their Parent Comets" published by Cambridge University Press (2006). He is also credited with the identification of the parent body of the Quadrantid meteor shower. As it happens, he graduated from Leiden Observatory in 1992, before joining the SETI Institute.
Note: This story has been adapted from material provided by SETI Institute.

Fausto Intilla

sabato 13 ottobre 2007

Search For Extraterrestrial Intelligence: Allen Telescope Array Begins Scientific Observations


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Science Daily — The University of California, Berkeley and the SETI Institute have announced that the first 42 radio dishes of the Allen Telescope Array (ATA) have been activated and collecting scientific data from the far reaches of the universe. This is the first phase of a planned 350 radio dishes that will advance the capabilities of radio astronomy research. Paul G. Allen, Microsoft co-founder and philanthropist whose foundation donated seed money that started the project in 2001, joined representatives of UC Berkeley and the SETI Institute to launch the array.
“This is a great day for the science of radio astronomy and the study of the cosmos,” said Leo Blitz, UC Berkeley professor of astronomy and director of the university’s Radio Astronomy Laboratory, which is building the ATA with the SETI Institute. “Thanks to a unique intersection between the best in science, advanced, innovative technology and bold philanthropy, many secrets of the universe are a little closer to being revealed.”
"This project represents a potential breakthrough in building large arrays of radio telescopes that are extremely cost effective,” said Paul G. Allen, primary funder of the ATA. “As now deployed and with plenty of room for growth in the future, the telescope can fulfill a multitude of uses, including broad radio sky surveys and the search for evidence of extraterrestrial technology. I’m pleased to be able to contribute to such an important advancement and help build on the work this new telescope will do in the future. My hat is off to the team that worked so hard these last seven years to accomplish this significant milestone.”
Every object in space emits radio waves that can be collected and studied. From observation of these signals, radio astronomers can create a picture of astronomical bodies and events at great distances, revealing detail not discernable by telescopes operating at other wavelengths. The ATA will acquire data in a new way, imaging a large piece of the sky at once. What sets the ATA apart from earlier radio telescopes is its ability to collect and, analyze more information about celestial objects, and do this simultaneously for several projects. In addition, observational surveys can be made with greater speed than any previous or existing radio device.
“For SETI, the ATA’s technical capabilities exponentially increase our ability to search for intelligent signals, and may lead to the discovery of thinking beings elsewhere in the universe,” said astronomer Seth Shostak of the SETI Institute in Mountain View, Calif. “It is the first major telescope in the world built specifically for undertaking a search for extraterrestrial intelligence.”
The ATA opens the doors to a new era of scientific progress. The telescope’s potential discoveries include a better understanding of exploding stars (supernovas), black holes, and new, exotic astronomical objects that are predicted but not yet observed. It will also provide expanded search capabilities to determine if intelligent civilizations have evolved around other stars. The ATA is the first panchromatic, wide-angle, snapshot, radio camera ever built. It is the most effective tool to create radio images of a vast area of the sky ever placed in the hands of researchers.
Located in an arid valley near the town of Hat Creek, just north of Lassen Volcanic National Park in northern California, the new array is already collecting important data. The first test images, released today from data gathered by the 42 ATA telescopes, include a radio map of the nearby Andromeda Galaxy (M31) and the Triangulum Galaxy (M33).
Beyond its speed and ability to both garner and analyze data, the ATA is also the first centimeter wavelength radio telescope with the ability to multi-task. While making innovative observations for radio astronomy, it can simultaneously interrogate solar-type stars for artificially produced signals that would reveal the presence of extraterrestrial intelligence.
This new capability increases many-fold the time astronomers can devote to large-scale surveys of the stars, as well as expanding the radio frequency band over which they can search. For SETI, in particular, this means that over the next two-dozen-years, the ATA will get a thousand times more data than has been accumulated in the past 45 years.
The ATA uses mass-produced, 20-foot diameter radio dishes and commercial telecommunications technologies combined with an innovative receiver design, and state-of-the-art digital signal processing technology. Working together, these small dishes create a telescope with a wide field of view ideally suited to rapidly surveying the sky. The layout of the 42 dishes was created by a computer model and is optimized to provide high quality radio imagery of the sky. The ATA can also filter out noise from man-made interference that in many radio telescopes would render much of the data unusable. The array can be easily upgraded as new advances in computer or telecommunications technology become available.
The total cost of the project to date, including research, development and construction costs for the array and the necessary radio astronomy and SETI signal detectors, is $50 million. The first phase of this project was funded through generous grants from the Paul G. Allen Family Foundation totaling $25 million. UC Berkeley, the SETI Institute, the National Science Foundation, Xilinx, Nathan Myhrvold, Greg Papadopoulos, and other corporations and individual donors contributed additional funding. Both UC Berkeley and the SETI Institute are engaging in additional fundraising efforts to complete the full 350-dish array.
The full 350-dish array, when completed in approximately three years, will have unprecedented research capabilities. Capitalizing on constant advancements in computer technology, the ATA will be manufactured at a fraction of the cost of traditional instruments. The ATA team is prepared to install more dishes as additional funding is secured.
Note: This story has been adapted from material provided by SETI Institute.

Fausto Intilla

giovedì 11 ottobre 2007

New Isotope Molecule May Add To Venus' Greenhouse Effect


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Science Daily — Planetary scientists on both sides of the Atlantic have tracked down a rare molecule in the atmospheres of both Mars and Venus. The molecule, an exotic form of carbon dioxide, could affect the way the greenhouse mechanism works on Venus.
The discovery is being announced at the annual meeting of the American Astronomical Society's Division of Planetary Sciences in Orlando, Florida. Its presence could affect the way the greenhouse mechanism works on Venus. The mystery began back in April 2006, soon after ESA's Venus Express arrived at the second planet in the Solar System.
A European team including members from France, Belgium and Russia lead by Jean-Loup Bertaux, Service d'Aeronomie du CNRS, France and Ann-Carine Vandaele, Institut d'Aeronomie Spatiale de Belgique, were using their Infrared Atmospheric Spectrometer (SOIR) instrument to measure solar occultations.
To do this, the instrument watches the Sun set behind Venus, allowing the scientists to study the way specific wavelengths of light are absorbed by the planet's atmosphere. These wavelengths and the level of absorption then give away the identity and amount of gases in the atmosphere.
The team saw an unidentified signature at 3.3 micrometres in the mid-infrared region of the spectrum. "It was conspicuous and systematic, increasing with depth in the atmosphere during the occultation, so we knew it was real," says Bertaux.
The team kept their discovery confidential as they attempted to identify the molecule responsible. They thought at first that it must be an organic molecule. These molecules contain carbon and hydrogen. However, none of the known organic molecules fitted well with the observations.
Then, in December 2006, Mike Mumma of NASA's Goddard Space Flight Center, Maryland, enquired whether the SOIR team was seeing anything special on Venus at 3.3 microns. He had discovered an unidentified spectral signature at that wavelength using telescopes on Hawaii pointing at Mars. The two teams compared the absorption signatures: they were identical.
This was a big clue. Both the atmospheres of Mars and Venus are composed of 95% carbon dioxide, although Venus's atmosphere is much thicker than the one at Mars. The American team suggested that the signature could be coming from an isotope of carbon dioxide, where one oxygen atom is 'normal', with eight protons and eight neutrons, while the other has eight protons and ten neutrons. Such an isotope makes up about 1% of carbon dioxide on Earth; the rest contains two normal oxygen atoms.
However, no one had previously seen the molecule absorb at 3.3 micrometres. An investigation by three independent groups, one led by Mumma in America; Sergei Tashkun and Valery Perevalov at Tomsk State University, Russia; and Richard Dahoo at Service d'Aéronomie du CNRS, France, all came to the same conclusion. The signature could be caused by a rare transition only possible in the isotope.
The different weights of the oxygen atoms allow the molecule to alter its vibration in two ways simultaneously, whereas normal molecules can only change one state at a time.
This rare transition allows it to absorb even more energy and so contribute even more to the greenhouse effect on Venus. On Earth, however, there is 250 000 times less carbon dioxide so its additional contribution to our greenhouse effect will be small.
Note: This story has been adapted from material provided by European Space Agency.

Fausto Intilla

Dusty Winds Bursting Out Of Black Holes May Have Seeded Planets, Life


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Science Daily — The hit song that proclaimed, "All we are is dust in the wind," may have some cosmic truth to it. New findings from NASA's Spitzer Space Telescope suggest that space dust -- the same stuff that makes up living creatures and planets -- was manufactured in large quantities in the winds of black holes that populated our early universe.
The findings are a significant new clue in an unsolved mystery: where did all the dust in the young universe originate?
"We were surprised to find what appears to be freshly made dust entrained in the winds that blow away from supermassive black holes," said Ciska Markwick-Kemper of the University of Manchester, U.K. Markwick-Kemper is lead author of a new paper appearing in an upcoming issue of the Astrophysical Journal Letters. "This could explain where the dust came from that was needed to make the first generations of stars in the early universe."
Space dust is essential to the formation of planets, stars, galaxies and even life as we know it. The dust in our corner of the universe was piped out by dying stars that were once a lot like our sun. But, when the universe was less than a tenth of its present age of 13.7 billion years, sun-like stars hadn't been around long enough to die and make dust. So, what produced the precious substance back when the universe was just a toddler?
Theorists have long-postulated that short-lived, massive exploding stars, or supernovae, might be the source of this mysterious dust, while others have proposed that a type of energetic, growing supermassive black hole, called a quasar, could be a contributing factor. A quasar consists of a supermassive black hole surrounded by a dusty doughnut-shaped cloud that feeds it. Theoretically, dust could form in the outer portion of the winds that slowly blow away from this doughnut cloud.
"Quasars are like the Cookie Monster," said co-author Sarah Gallagher of the University of California at Los Angeles, who is currently a visiting astronomer at the University of Western Ontario, Canada. "They are messy eaters, and they can consume less matter than they spit out in the form of winds."
Nobody has found conclusive proof that either quasar winds or supernovae can create enough dust to explain what is observed in the early universe. Markwick-Kemper and her team decided to test the former theory and investigate a quasar, called PG2112+059, located in the center of a galaxy about 8 billion light-years way. Although this particular quasar is not located in the early universe, because it is closer, it is an easier target for addressing the question of whether quasars can make dust. The team used Spitzer's infrared spectrograph instrument to split apart infrared light from the quasar and look for signs of various minerals.
They found a mix of the ingredients that make up glass, sand, marble and even rubies and sapphires. While the mineral constituting glass was expected, the minerals for sand, marble and rubies were a surprise. Why? These minerals are not typically detected floating around galaxies, suggesting they could have been freshly formed in the winds rushing away from the quasar.
For instance, the ingredient that makes up sand, crystalline silicate, doesn't survive for long free-floating in space. Radiation from stars zaps the minerals back to an amorphous, glass-like state. The presence of crystalline silicate therefore suggests something -- possibly the quasars winds -- is churning out the newly made substance.
Markwick-Kemper and her team say the case of the missing dust is not firmly shut. They hope to study more quasars for further evidence of their dust-making abilities. Also, according to the astronomers, quasars may not be the only source of dust in the early universe. "Supernovae might have been more important for creating dust in some environments, while quasars were more important in others," said Markwick-Kemper. "For now, we are very excited to have identified the different species of dust in a quasar billions of light-years away."
Other authors of this paper include Dean Hines of the Space Science Institute, Boulder, Colo., and Jeroen Bouwman of the Max Planck Institute for Astronomy, Heidelberg, Germany. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. Spitzer's infrared spectrograph was built by Cornell University, Ithaca, N.Y. Its development was led by Jim Houck of Cornell.
Note: This story has been adapted from material provided by NASA/Spitzer Space Telescope.

Fausto Intilla

lunedì 8 ottobre 2007

Multiwavelength Images Of Distant Universe Now Available On Google Sky


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Science Daily — A massive project to map a distant region of the Universe in multiple wavelengths--from x-rays through ultraviolet, visible, infrared, and radio waves--is currently releasing its data to both fellow scientists and the general public. It is the first data release from the AEGIS survey and the first release of multiwavelength data to take advantage of the capabilities of Google Sky, a new feature of Google Earth.
AEGIS--the All-wavelength Extended Groth Strip International Survey--combines the efforts of nearly 100 researchers from around the world observing the same small region of sky in all available wavelengths of the electromagnetic spectrum. The target area, called the Extended Groth Strip, covers an area the width of four full moons that is a hop, skip and jump from the end of the Big Dipper's handle. The AEGIS region has now been surveyed more intensively and with more telescopes than any other region of the sky.
"We are still sorting through this treasure trove to discover the many gems of information it contains," said Sandra Faber, University Professor and chair of astronomy and astrophysics at the University of California, Santa Cruz. Faber worked with Jeffrey Newman of the University of Pittsburgh, Shui Kwok of the W. M. Keck Observatory in Hawaii, UCSC graduate student Genevieve Graves, and many other members of the AEGIS team to coordinate the data release through Google Sky.
"We are looking back to a time when the universe was more than half its current age and when galaxies were forming most of their stars," says Professor Kirpal Nandra, from the Department of Physics and who is leading the project from Imperial College London. He added: "With the X-ray images we are looking at black holes, which are at the centre of galaxies, to try to work out how the growth of black holes is linked to the growth of the galaxy itself."
"It is clear that serving astronomical data through Google Sky is going to revolutionize the way astronomers communicate, both among themselves and with the public," Faber said. "AEGIS is proud and pleased to be the pathfinder dataset for Google Sky's new multiwavelength capabilities."
Color images from four different satellite telescopes, as well as numerous data catalogs, from x-ray to radio wavelengths, giving brightnesses and distances of tens of thousands of galaxies are now available. Google Earth's new Sky feature provides a fast and powerful access tool for astronomical data similar to what the popular Google Earth software has provided for terrestrial data.
"AEGIS images projected onto the celestial sphere show how it would look with infrared, ultraviolet, or x-ray eyes," Faber said. "Some galaxies look brighter at certain wavelengths than others, which carries important information about their composition and the processes occurring within them."
The rapid browsing abilities of Google Sky provide a new way to compare many views of a single galaxy or a set of galaxies instantly. For researchers, it is a powerful tool for exploring AEGIS's massive data sets. The AEGIS collaboration is also making all of its data available on its website, so that researchers can download it directly.
Of the four color images in the first AEGIS data release, the most detailed is a visible-light image stitched together from 63 separate pointings of the Hubble Space Telescope. This image forms the base map in Google Sky. Stretching twice the width of the full Moon, it is the largest unbroken color mosaic ever made with Hubble and contains images of approximately 50,000 faraway galaxies. Light has traveled for more than 10 billion years from the most distant ones, giving us pictures of them as they looked long ago, more than three-quarters of the way back to the Big Bang. The exquisite detail of the Hubble images shows infant and adolescent galaxies as they began to form.
The second image shows the same galaxies through the ultraviolet eyes of NASA's Galaxy Evolution Explorer (GALEX) satellite. Ultraviolet wavelengths are shorter and bluer than those of visible light. Massive, hot young stars that are just forming produce ultraviolet light in abundance. Brightness in the GALEX image therefore provides a measure of the rate at which each galaxy is forming stars. Galaxies that contain relatively few hot, young stars or that are obscured by either their own dust or diffuse gas along our line of sight will appear redder in the GALEX image.
The third view is a mosaic of images taken with the Infrared Array Camera on NASA's Spitzer Space Telescope, the last mission in NASA's Great Observatory series. Near-infrared brightness is closely related to the total number of stars in a galaxy, while the colors of a galaxy as seen through infrared eyes reveal information on both its contents (stars and dust) and its distance from us.
The fourth image was produced with data from NASA's Chandra X-ray Observatory. In the objects seen by Chandra, highly energetic x-ray radiation has been produced when gas is spiralling into a supermassive black hole, like those believed to lie at the center of almost every galaxy. Many of the x-ray-emitting objects lie buried within otherwise normal-looking galaxies. In the x-ray images, the bluest objects are the ones most obscured by gas within their host galaxies.
In the objects seen by Chandra, X-ray radiation has been produced when gas is spiralling into a super massive black hole, like those believed to lie at the centre of almost every galaxy. Many of the X-ray emitting objects lie buried within otherwise normal-looking galaxies. In these X-ray images, the bluest objects are the ones most obscured by gas within their host galaxies, according to researchers at Imperial College in London.
In combination, these images simultaneously measure the sizes and shapes of galaxies, their current rates of star formation, the total number of stars each galaxy has already formed, and the rate at which a black hole at its center is actively accreting matter. All of this information provides separate clues to help scientists understand the evolution of galaxies over the past 10 billion years.
These images from space-based telescopes are tied together by the spectra of nearly 15,000 AEGIS galaxies taken with the Keck II Telescope in Hawaii as part of the DEEP2 Galaxy Redshift Survey, led by Faber and Marc Davis of UC Berkeley. Among other information, these spectra enable astronomers to determine distances to these objects, which is crucial for distinguishing small galaxies in the foreground from giant galaxies that appear faint because they are so far away. Once they have determined the distance to a galaxy, astronomers know how far back in time light left it. The most distant galaxies in the AEGIS survey are seen as they looked only a few billion years after the Big Bang.
With the Sky feature in Google Earth, users can pan and zoom around all of these pictures of the sky to select individual galaxies for closer inspection. By adjusting the transparency of each image, the user can focus on only one of the AEGIS images at a time, or look at a combination (e.g., the GALEX image superimposed on Hubble). Clicking on galaxies in AEGIS catalogs brings up their distances and intrinsic properties. A further mouse click links the user to the Keck spectrum and additional information being used for AEGIS science studies.
This first data release from AEGIS is only the first step. Later releases will feature images taken at far-infrared and radio wavelengths. A master catalog is being prepared that combines information from all of AEGIS's many views of the sky. As future images are prepared, they and the growing data catalogs will all be linked through Google Sky.
The AEGIS web site gives more information about the survey, science results to date, and links to additional images and data that can be downloaded. The many windows on the universe provided by AEGIS have already produced a variety of new results on the evolution of galaxies, and many more new findings from the AEGIS team will appear soon, according to Newman.
"With this public release of both interactive images and the underlying data catalogs, the full astronomical community will now be able to take advantage of this powerful new dataset," he said.
The AEGIS teams that contributed images and data for this release include the Hubble team led by Marc Davis of UC Berkeley; the Chandra team lead by Kirpal Nandra of Imperial College, London; the Spitzer team led by Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics; and the GALEX team led by Chris Martin of the California Institute of Technology. Funding for the AEGIS collaboration was provided by the National Science Foundation and NASA.
Images are available at: http://earth.google.com/gallery/index.html
Note: This story has been adapted from material provided by University of California, Santa Cruz.

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giovedì 4 ottobre 2007

Earth-like Planet Forming In Nearby Star System, Astronomers Believe


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Science Daily — An Earth-like planet is likely forming 424 light-years away in a star system called HD 113766, say astronomers using NASA's Spitzer Space Telescope.
Scientists have discovered a huge belt of warm dust – enough to build a Mars-size planet or larger – swirling around a distant star that is just slightly more massive than our sun.
The dust belt, which they suspect is clumping together into planets, is located in the middle of the system's terrestrial habitable zone. This is the region around a star where liquid water could exist on any rocky planets that might form. Earth is located in the middle of our sun's terrestrial habitable zone.
At approximately 10 million years old, the star is also at just the right age for forming rocky planets.
"The timing for this system to be building an Earth is very good," says Dr. Carey Lisse, of the Johns Hopkins University Applied Physics Laboratory, Laurel, Md. "If the system was too young, its planet-forming disk would be full of gas, and it would be making gas-giant planets like Jupiter instead. If the system was too old, then dust aggregation or clumping would have already occurred and all the system's rocky planets would have already formed."
According to Lisse, the conditions for forming an Earth-like planet are more than just being in the right place at the right time and around the right star – it's also about the right mix of dusty materials.
Using Spitzer's infrared spectrometer instrument, he determined that the material in HD 113766 is more processed than the snowball-like stuff that makes up infant solar systems and comets, which are considered cosmic "refrigerators" because they contain pristine ingredients from the early solar system. However, it is also not as processed as the stuff found in mature planets and the largest asteroids. This means the dust belt must be in a transitional phase, when rocky planets are just beginning to form.
How do scientists know the material is more processed than that of comets? From missions like NASA's Deep Impact – in which an 820-pound impactor spacecraft collided with comet Tempel 1 – scientists know that early star systems contain a lot of fragile organic material. That material includes polycyclic aromatic hydrocarbons (carbon-based molecules found on charred barbeque grills and automobile exhaust on Earth), water ice, and carbonates (chalk). Lisse says that HD 113766 does not contain any water ice, carbonates or fragile organic materials.
From meteorite studies on Earth, scientists also have a good idea of what makes up asteroids – the more processed rocky leftovers of planet formation. These studies tell us that metals began separating from rocks in Earth's early days, when the planet's body was completely molten. During this time, almost all the heavy metals fell to Earth's center in a process called "differentiation." Lisse says that, unlike planets and asteroids, the metals in HD 113766 have not totally separated from the rocky material, suggesting that rocky planets have not yet formed.
"The material mix in this belt is most reminiscent of the stuff found in lava flows on Earth. I thought of Mauna Kea material when I first saw the dust composition in this system – it contains raw rock and is abundant in iron sulfides, which are similar to fool's gold," says Lisse, referring to a well-known Hawaiian volcano.
"It is fantastic to think we are able to detect the process of terrestrial planet formation. Stay tuned — I expect lots more fireworks as the planet in HD113766 grows," he adds.
Lisse's article, Circumstellar Dust Created by Terrestrial Planet Formation in HD 113766, will be published in an upcoming issue of Astrophysical Journal. He will also present his findings at the upcoming meeting of the American Astronomical Society Division for Planetary Sciences in Orlando, Fla. Lisse's research was funded through a Johns Hopkins Applied Physics Laboratory Stuart S. Janney Fellowship and a Spitzer Space Telescope guest observer grant.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.
The University of Maryland is responsible for overall Deep Impact mission science, and project management is handled by JPL.
Note: This story has been adapted from material provided by Johns Hopkins University.

Fausto Intilla

venerdì 28 settembre 2007

Mysterious Energy Burst Stuns Astronomers


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Science Daily — In a shock finding, astronomers using CSIRO’s Parkes telescope have detected a huge burst of radio energy from the distant universe that could open up a new field in astrophysics.
The research team, led by Assistant Professor Duncan Lorimer of West Virginia University, reported its discovery in the journal Science Express.
The radio burst appears to have originated at least one-and-a-half billion light-years [500 Mpc] away but was startlingly strong.
“Normally the kind of cosmic activity we’re looking for at this distance would be very faint but this was so bright that it saturated the equipment,” said Professor Matthew Bailes of Swinburne University in Melbourne.
The burst was so bright that at the time it was first recorded it was dismissed as man-made radio interference. It put out a huge amount of power (10exp33 Joules), equivalent to a large (2000MW) power station running for two billion billion years.
“The burst may have been produced by an exotic event such as the collision of two neutron stars or be the last gasp of a black hole as it evaporates completely,” Professor Lorimer said.
The burst lasted just five milliseconds.
It was found by David Narkevik, an undergraduate at the West Virginia University, when he re-analysed data taken with the Parkes telescope six years ago.
Although they’ve found only one burst, the astronomers can estimate how often they occur.
“We’d expect to see a few bursts over the whole sky every day,” said Dr John Reynolds, Officer in Charge at CSIRO’s Parkes Observatory.
“A new telescope being built in Western Australia will be ideal for finding more of these rare, transient events.
”The Australian SKA Pathfinder, which is going to be built by 2012, will have a very wide field of view—be able to see a very large piece of sky—which is exactly what you want for this kind of work,” he said.
Meanwhile, the researchers will comb archived data from the Parkes telescope for more radio bursts.
The discovery of the radio burst is similar to the discovery of gamma-ray bursts in the 1970s, when military satellites revealed flashes of gamma-rays appearing all over the sky. One kind—the so-called long-period bursts—was eventually identified as the explosion (supernova) of a massive star with the associated formation of a black hole.
Note: This story has been adapted from a news release issued by CSIRO Australia.

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mercoledì 26 settembre 2007

NASA Spacecraft Is A 'Go' For Asteroid Belt


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Science Daily — Launch and flight teams are in final preparations for the planned Sept. 27 liftoff from Pad 17-B at Cape Canaveral Air Force Station, Fla., of NASA's Dawn mission. The Dawn spacecraft will venture into the heart of the asteroid belt, where it will document in exceptional detail the mammoth rocky asteroid Vesta, and then, the even bigger icy dwarf planet Ceres.
"If you live in the Bahamas this is one time you can tell your neighbor, with a straight face, that Dawn will rise in the west," said Dawn Project Manager Keyur Patel of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Weather permitting, we are go for launch Thursday morning -- a little after dawn."
Dawn's Sept. 27 launch window is 7:20 to 7:49 a.m. Eastern Daylight Time (4:20 to 4:49 a.m. Pacific Daylight Time). At the moment of liftoff, the Delta II's first-stage main engine along with six of its nine solid-fuel boosters will ignite. The remaining three solids are ignited in flight following the burnout of the first six. The first-stage main engine will burn for 4.4 minutes. The second stage will deposit Dawn in a 185-kilometer-high (100- nautical-mile) circular parking orbit in just under nine minutes. At about 56 minutes after launch, the rocket's third and final stage will ignite for approximately 87 seconds. When the third stage burns out, actuators and push-off springs on the launch vehicle will separate the spacecraft from the third stage.
"After separation, the spacecraft will go through an automatic activating sequence, including stabilizing the spacecraft, activating flight systems and deploying Dawn's two massive solar arrays," said Patel. "Then and only then will the spacecraft energize its transmitter and contact Earth. We expect acquisition of signal to occur anywhere from one-and-a-half hours to three-and-a-half hours after launch."
The Dawn mission will explore Vesta, and later Ceres, because these two asteroid belt behemoths have been witness to so much of our solar system's history.
"Visiting both Vesta and Ceres enables a study in extraterrestrial contrasts," said Dawn Principal Investigator Christopher Russell of the University of California, Los Angeles. "One is rocky and is representative of the building blocks that constructed the planets of the inner solar system. The other may very well be icy and represents the outer planets. Yet, these two very diverse bodies reside in essentially the same neighborhood. It is one of the mysteries Dawn hopes to solve."
Using the same spacecraft to reconnoiter two different celestial targets makes more than fiscal sense. It makes scientific sense. By utilizing the same set of instruments at two separate destinations, scientists can more accurately formulate comparisons and contrasts. Dawn's science instrument suite will measure mass, shape, surface topography and tectonic history, elemental and mineral composition, as well as seek out water-bearing minerals. In addition, the Dawn spacecraft itself and the way it orbits both Vesta and Ceres will be used to measure the celestial bodies' gravity fields.
"Understanding conditions that lead to the formation of planets is a goal of NASA's mission of exploration," said David Lindstrom, Dawn program scientist at NASA Headquarters, Washington. "The science returned from Vesta and Ceres could unlock many of the mysteries of the formation of the rocky planets including Earth."
Before all this celestial mystery unlocking can occur, Dawn has to reach the asteroid belt and its first target – Vesta. This is a four-year process that begins with launch and continues with the firing of three of the most efficient engines in NASA's space motor inventory - ion propulsion engines. Employing a complex commingling of solar-derived electric power and xenon gas, these frugal powerhouses must fire for months at a time to propel as well as steer Dawn. Over their eight-year, almost 4-billion-mile lifetime, these three ion propulsion engines will fire cumulatively for about 50,000 hours (over five years) - a record for spacecraft.
The Dawn mission to asteroid Vesta and dwarf planet Ceres is managed by JPL, for NASA's Science Mission Directorate, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. The University of California, Los Angeles, is responsible for overall Dawn mission science. Other scientific partners include: Los Alamos National Laboratory, New Mexico; Max Planck Institute for Solar System Research, Katlenburg, Germany; and Italian National Institute of Astrophysics, Rome. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft.
Note: This story has been adapted from a news release issued by NASA/ Jet Propulsion Laboratory.

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martedì 18 settembre 2007

Life On Mars 'Pregnancy Test' Successfully Launched


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Science Daily — Key components of a new approach to discover life on Mars were successfully launched into space Friday as part of a twelve-day, low-Earth orbit experiment to assess their survivability in the space radiation environment--a prelude future journeys to Mars.
The new approach is based on technology similar to that used in pregnancy test kits. The so-called immunoassays are embodied in the "Life Marker Chip" (LMC) experiment, which has the potential to detect trace levels of biomarkers in the Martian environment. Biomarkers are molecular fingerprints that indicate if life currently is, or ever was, present on Mars.
The LMC experiment has been proposed for the European Space Agency's ExoMars rover mission, which is planned for launch in 2013. The LMC experiment is in the development phase and is led by an international consortium with researchers including Andrew Steele, a staff member of Carnegie's Geophysical Laboratory in the United States, and scientists from the United Kingdom, The Netherlands, and Germany.
For the current mission, the consortium developed a tiny component, measuring only 1.5 inches x 1.6 inches x .5 inch ( 3.8 cm x 4.1 cm x 1.3 cm) and housing over 2000 samples, to test that the key molecular components to be used in the LMC technology can survive the rigors of space.
The experiment was launched from Baikonur Cosmodrome in Kazakhstan as part of the European Space Agency's BIOPAN-6 experiment platform. The LMC components will experience both weightlessness and the harsh space radiation environment while orbiting the Earth 180 times at an altitude of up to 190 miles (308 km) during the 11.8 day mission.
The BIOPAN-6 platform is mounted on the outside of an un-manned Russian FOTON spacecraft. Once in space the BIOPAN-6 platform will open to expose its contents directly to the space environment, testing both their resistance to space radiation and the space vacuum, before closing and returning to Earth on September 25th. The LMC components will then be taken back to laboratories in the United Kingdom and the United States to analyze the effect of the space flight.
The lead members of the consortium involved in the current mission are Deutsches Zentrum für Luft- und Raumfahrt (DLR) (Germany), Cranfield University (UK), Carnegie Institution of Washington (USA) and University of Leicester (UK).
Dr. Andrew Steele from the Carnegie Institution of Washington (USA) and one of the initial experiment proposers said, "in the USA we are currently flying related technology and components within the protected environment of the International Space Station (ISS) but this will be the first time that these types of materials will have flown unprotected in space in a manner similar to a flight to Mars."
Dr. Lutz Richter of DLR (Germany) and the principal investigator for the current experiment said, "This experiment is the culmination of a number of years of hard work and ground based tests to prove the viability of the LMC technology."
Dr. David Cullen, from Cranfield University (UK) and who leads the scientific input into the current experiment, said, "this will be our first space experiment to demonstrate our belief that immunoassay technology will have an important future role in space exploration and the search for life elsewhere in the Solar System."
Dr. Mark Sims from the University of Leicester (UK) and who heads the overall LMC project said, "this mission will be an important stepping stone in our ultimate goal of putting a LMC experiment on the surface of Mars and using it to search for evidence of Life."
A number of other people, organizations and companies have contributed to the experiment and these include Haptogen Ltd. (Aberdeen, UK), Oklahoma State University (USA), LioniX BV (Enschede, NL), Technische Universität München (Germany) and Dr Jan Toporski, formally of Christian-Albrechts-Universität zu Kiel (Germany).
*This release was adapted from a release by Cranfield Health, Cranfield University, Silsoe, Bedfordshire MK45 4DT, United Kingdom.
Note: This story has been adapted from a news release issued by Carnegie Institution.

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venerdì 14 settembre 2007

Japan's KAGUYA Spacecraft Blasts Off To Explore The Moon


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Science Daily — Japan has successfully launched a new unmanned spacecraft to explore the Moon -- the largest lunar mission since the Apollo program.
Mitsubishi Heavy Industries, Ltd. and the Japan Aerospace Exploration Agency (JAXA) announced the launch of the Lunar Orbit Explorer "KAGUYA" (SELENE) by the H-IIA Launch Vehicle No. 13 (H-IIA F13) at 10:31:01 a.m. on September 14, 2007 (Japan Standard Time, JST) from the Tanegashima Space Center. The launch vehicle flew smoothly, and, at about 45 minutes and 34 seconds after liftoff, the separation of the KAGUYA was confirmed.
The mission of the SELenological and ENgineering Explorer "KAGUYA" (SELENE), Japan’s first large lunar explorer, is being keenly anticipated by many countries.
The major objectives of the mission are to understand the Moon’s origin and evolution, and to observe the moon in various ways in order to utilize it in the future. The lunar missions that have been conducted so far have gathered a large amount of information on the Moon, but the mysteries of its origin and evolution have been left unsolved.
KAGUYA will investigate the entire moon in order to obtain information on its elemental and mineralogical composition, its geography, its surface and sub-surface structure, the remnant of its magnetic field, and its gravity field. The results are expected to lead to a better overall understanding of the Moon’s evolution.
At the same time, the observation equipment installed on the orbiting satellite will observe plasma, the electromagnetic field and high-energy particles. The data obtained in this way will be of great scientific importance for exploring the possibility of using the moon for human endeavors.
KAGUYA’s configuration and mission
KAGUYA consists of the Main Orbiter and two small satellites (Relay Satellite and VRAD Satellite). The Main Orbiter will reach the vicinity of the Moon. Once it has reached the Moon, it will be placed into a peripolar orbit at an altitude of 100 km. The Relay Satellite will be placed in an elliptic orbit at an apogee of 2400 km, and will relay communications between the Main Orbiter and the ground station. The VRAD Satellite will play a significant role in measuring the gravitational field around the Moon. The Main Orbiter will be employed for about one year and will observe the entire Moon.
Note: This story has been adapted from a news release issued by Japan Aerospace Exploration Agency.

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giovedì 13 settembre 2007

Opportunity Takes A Dip Into Victoria Crater


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Science Daily — NASA's Mars Exploration Rover Opportunity entered Victoria Crater for the first time September 11, 2007. It radioed home information via a relay by NASA's Mars Odyssey orbiter, reporting its activities for the day.
Opportunity drove far enough in -- about four meters (13 feet) -- to get all six wheels past the crater rim. Then it backed uphill for about three meters (10 feet). The driving commands for the day included a precaution for the rover to stop driving if its wheels were slipping more than 40 percent. Slippage exceeded that amount on the last step of the drive, so Opportunity stopped with its front pair of wheels still inside the crater.
"We will do a full assessment of what we learned from the drive today and use that information to plan Opportunity's descent into the crater," said John Callas, rover project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Once Opportunity begins its extended exploration inside the crater, the rover will investigate layered rocks exposed on the interior slope.
NASA's Mars Exploration Rover Opportunity entered Victoria Crater during the rover's 1,291st Martian day, or sol, (Sept. 11, 2007). The rover team commanded Opportunity to drive just far enough into the crater to get all six wheels onto the inner slope, and then to back out again and assess how much the wheels slipped on the slope.
The driving commands for the day included a precaution for the rover to stop driving if the wheels were slipping more than 40 percent. Slippage exceeded that amount on the last step of the drive, so Opportunity stopped with its front pair of wheels still inside the crater. The rover team planned to assess results of the drive, then start Opportunity on an extended exploration inside the crater.
Note: This story has been adapted from a news release issued by NASA, Jet Propulsion Laboratory.

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mercoledì 12 settembre 2007

Mars-Bound Phoenix Returns First Photo From Trip


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Science Daily — A camera flying aboard The University of Arizona-led Phoenix Mars Lander took its first picture during cruise and sent it back to Earth on Sept. 6. The lander's Robotic Arm Camera took the photo looking into the Robotic Arm's scoop. Both instruments are encased in a protection biobarrier, to ensure no Earth organisms are carried to Mars.
"It is a nice, clean picture with good sharp focus. One of these days it will be filled with Martian dirt," said Peter Smith, Phoenix principal investigator at the UA. "We have special pride in this, as it is a UA-German product."
The Robotic Arm Camera took an image of the Robotic Arm scoop using its red LED (Light-Emitting Diode) lamp. Human eyes see this image only in shades of gray, so the picture has been enhanced in false color to better represent what the camera sees.
Images from the Robotic Arm Camera, one of five imaging instruments on the lander, will be the only pictures taken and returned to Earth until Phoenix approaches and lands on Mars on May 25, 2008. Additional images will be taken by the Robotic Arm Camera later in the cruise stage.
The Robotic Arm Camera check was one of a series of instrument tests being completed as Phoenix cruises toward the red planet. Phoenix was about 57 million miles from Earth when the image was sent back. It is traveling at 76,000 miles per hour in relation to the sun.
On Mars, the Robotic Arm will dig trenches, scoop up soil and water-ice samples and deliver them to several instruments on the lander's deck for chemical and geological analysis.
The Robotic Arm Camera, built by the UA and Max Planck Institute, is attached to the Robotic Arm just above the scoop and will provide close-up, full-color images of the Martian surface, prospective soil and water-ice samples, samples collected in the scoop before delivery to the lander's science deck, and of the floor and side walls of the trenches. Phoenix's Robotic Arm was provided by the Jet Propulsion Laboratory, and the arm's scoop was manufactured by Honeybee Robotics of New York.
Phoenix launched from Cape Canaveral Air Force Station, Fla., on Aug. 4. It will fly to a site farther north than any previous Mars landing.
The solar-powered lander will robotically dig to underground ice and will run laboratory tests assessing whether the site could have ever been hospitable to microbial life. The instruments will also look for clues about the history of the water in the ice. They will monitor arctic weather as northern Mars' summer progresses toward fall, until solar energy fades and the mission ends. The Phoenix mission is led by Peter Smith of The University of Arizona, Tucson, with project management at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and development partnership at Lockheed Martin, Denver. International contributions are provided by the Canadian Space Agency; the University of Neuchatel, Switzerland; the Universities of Copenhagen and Aarhus, Denmark; the Max Planck Institute, Germany; and the Finnish Meteorological Institute.
Note: This story has been adapted from a news release issued by National Aeronautics And Space Administration.
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martedì 11 settembre 2007

What Is Dark Energy? 'Beyond Einstein' Program Aims To Investigate


Source:

Science Daily — NASA and the U.S. Department of Energy should pursue the Joint Dark Energy Mission (JDEM) as the first mission in the "Beyond Einstein" program, according to a new report from the National Research Council.
Beyond Einstein is NASA's research roadmap for five proposed mission areas to study the most compelling questions at the intersection of physics and astronomy.
The committee that wrote the report added that another proposed mission to detect gravitational waves using the Laser Interferometer Space Antenna (LISA) should eventually become the flagship mission of Beyond Einstein, given that it is likely to provide an entirely new way to observe the universe. However, LISA needs more testing before a launch can be planned, whereas the Joint Dark Energy Mission is ready now for a competitive selection of mission concept proposals.
Prompted by Congress and the Office of Science and Technology Policy, NASA and DOE asked the committee to assess the five proposed mission areas and recommend one for first development and launch. NASA's Beyond Einstein program, set to begin in 2009, is comprised of two astronomical observatories, Constellation-X and LISA, as well as a series of probes: the Inflation Probe (IP), the Black Hole Finder Probe (BHFP), and JDEM.
"All of the mission areas in the Beyond Einstein program have the potential to fundamentally alter our understanding of the universe," said committee co-chair Charles F. Kennel, distinguished professor and director of the Environment and Sustainability Initiative at the University of California, San Diego. "But JDEM will provide direct insight into a key Beyond Einstein science question, and is the most technically feasible option for immediate development."
Of particular interest to researchers is whether the acceleration of the expansion of the universe varies over time. So far, three specific mission plans have been studied in this area: the Supernova Acceleration Probe (SNAP), the Dark Energy Space Telescope (DESTINY), and the Advanced Dark Energy Physics Telescope (ADEPT), but the eventual JDEM could be any one of the three or be based on a different option altogether.
The committee found that the underlying technology for a dark energy mission is, for the most part, in the prototype phase, and will require less development than most of the other missions. The potential gains for JDEM also outweigh its scientific risks, such as the possibility that the mission may not provide substantial insight beyond that provided by telescopes on the ground. The report recommends that NASA and DOE proceed immediately with a competition for mission proposals that will investigate the nature of dark energy with high precision.
The committee also recommended that NASA invest additional Beyond Einstein funds in technology development of the LISA program. LISA, which is funded through a partnership between NASA and the European Space Agency (ESA), is designed to detect gravitational waves arising from, among other phenomena, the merging of black holes.
The committee found that LISA will open up new ways of observing the universe, but must await results from ESA's "LISA Pathfinder" mission first. Scheduled for launch in 2009, LISA Pathfinder will test many of the new technologies required for the LISA program. Yet, some critical technologies, such as extended use of micro-Newton thruster technology, will not be tested. The report recommends that the development of these technologies should be a high priority for the Beyond Einstein program.
The report indicates that the three elements of Beyond Einstein that are not being recommended for immediate implementation are still important endeavors that should receive continued support. The committee found that because the Constellation-X mission is a general-purpose x-ray observatory capable of broad contributions to astrophysics, it should be funded and assessed in a broader context than the Beyond Einstein program.
The Black Hole Finder Probe and Inflation Probe missions will also make important scientific contributions; however, because of scope and technical readiness issues, they fell behind JDEM and LISA. The committee recommended that Constellation-X, Black Hole Finder Probe, and Inflation Probe receive continued support to prepare them for the next decadal survey of astronomy and astrophysics.
The study was sponsored by the U.S. Department of Energy and NASA. The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies.
Note: This story has been adapted from a news release issued by The National Academies.

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