Posted on by Fraser Cain

Satellite Can Tell When Ice is Melting

Resolute Bay seen by the Hyperion instrument aboard Earth Observing-1. Image credit: NASA. Click to enlarge
Spring thaw in the Northern Hemisphere was monitored by a new set of eyes this year — an Earth-orbiting NASA spacecraft carrying a new version of software trained to recognize and distinguish snow, ice, and water from space.

Using this software, the Space Technology 6 Autonomous Sciencecraft Experiment autonomously tracked changes in the cryosphere, the section of Earth that is frozen, and relayed the information and images back to scientists.

The software, developed by engineers at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., controls the Earth Observing-1 spacecraft. NASA’s Goddard Space Flight Center, Greenbelt, Md, manages the satellite. The software has taken more than 1,500 images of frozen lakes in Minnesota, Wisconsin, Quebec, Tibet and the Italian Alps, along with sea ice in Arctic and Antarctic bays.

While other spacecraft only capture images when they receive explicit commands to do so, for the last year Earth Observing-1 has been making its own decisions. Based on general guidelines from scientists, the spacecraft automatically tracks events such as volcano eruptions, floods and ice formation. The most recent software upgrade allows the spacecraft to accurately recognize cryosphere changes such as ice melting.

Previously, scientists spent several months developing software for Earth Observing-1 to detect changes in snow, water and ice. The new software is capable of learning by itself, and it took only a few hours for scientists to train it to recognize cryosphere changes. In fact, the new software has learned to classify the images so well that scientists plan to use it for the remainder of the mission.

“This new software is capable of a rudimentary form of learning, much the way a child learns the names of new objects,” said Dominic Mazzoni, the JPL computer scientist who developed the software. “Instead of programming the software using a complicated series of commands and mathematical equations, scientists play the role of a teacher, repeatedly showing the computer different images and giving feedback until it has correctly learned to tell them apart.”

On Earth Observing-1, the software searches for specific cryospheric events and reprograms the spacecraft to capture additional images of the event.

“The software has exceeded all of our expectations,” said Dr. Steve Chien, JPL principal investigator for the Autonomous Sciencecraft Experiment. “We have demonstrated that a spacecraft can operate autonomously, and the software has taken literally hundreds of images without ground intervention.”

Similar software has been used to distinguish between different types of clouds in images captured by JPL’s Multi-angle Imaging SpectroRadiometer, an instrument on NASA’s Terra spacecraft. Automatically identifying types of clouds from space will help scientists better understand Earth’s global energy balance and predict future climate trends.

Future versions of the software also might be used to track dust storms on Mars, search for ice volcanoes on Jupiter?s moon Europa, and monitor activity on Jupiter’s volcanically active moon Io. NASA’s New Millennium Program developed both the satellite and the software. The program is responsible for testing new technologies in space.

For more information on the Autonomous Sciencecraft Experiment on the Internet, visit: http://ase.jpl.nasa.gov .

For more information on the New Millennium Program on the Internet, visit: http://nmp.jpl.nasa.gov .

For information about the Earth Observing-1 spacecraft on the Internet, visit: http://eo1.gsfc.nasa.gov .

Original Source: NASA News Release

Posted on by Fraser Cain

Planet Found in Triple Star System

Artist’s animation shows the view from a hypothetical moon in orbit around the planet. Image credit: NASA. Click to enlarge
A NASA-funded astronomer has discovered a world where the sun sets over the horizon, followed by a second sun and then a third. The new planet, called HD 188753 Ab, is the first known to reside in a classic triple-star system.

“The sky view from this planet would be spectacular, with an occasional triple sunset,” said Dr. Maciej Konacki (MATCH-ee Konn-ATZ-kee) of the California Institute of Technology, Pasadena, Calif., who found the planet using the Keck I telescope atop Mauna Kea mountain in Hawaii. “Before now, we had no clues about whether planets could form in such gravitationally complex systems.”

The finding, reported in this week’s issue of Nature, suggests that planets are more robust than previously believed.

“This is good news for planets,” said Dr. Shri Kulkarni, who oversees Konacki’s research at Caltech. “Planets may live in all sorts of interesting neighborhoods that, until now, have gone largely unexplored.” Kulkarni is the interdisciplinary scientist for NASA’s planned SIM PlanetQuest mission, which will search for signs of Earth-like worlds.

Systems with multiple stars are widespread throughout the universe, accounting for more than half of all stars. Our Sun’s closest star, Alpha Centauri, is a member of a trio.

“Multiple-star systems have not been popular planet-hunting grounds,” said Konacki. “They are difficult to observe and were believed to be inhospitable to planets.”

The new planet belongs to a common class of extrasolar planets called “hot Jupiters,” which are gas giants that zip closely around their parent stars. In this case, the planet whips every 3.3 days around a star that is circled every 25.7 years by a pirouetting pair of stars locked in a 156-day orbit.

The circus-like trio of stars is a cramped bunch, fitting into the same amount of space as the distance between Saturn and our Sun. Such tight living quarters throw theories of hot Jupiter formation into question. Astronomers had thought that hot Jupiters formed far away from their parent stars, before migrating inward.

“In this close-knit system, there would be no room at the outskirts of the parent star system for a planet to grow,” said Konacki.

Previously, astronomers had identified planets around about 20 binary stars and one set of triple stars. But the stars in those systems had a lot of space between them. Most multiple-star arrangements are crowded together and difficult to study.

Konacki overcame this challenge using a modified version of the radial velocity, or “wobble,” planet-hunting technique. In the traditional wobble method, a planet’s presence is inferred by the gravitational tug, or wobble, it induces in its parent star. The strategy works well for single stars or far-apart binary and triple stars, but could not be applied to close-star systems because the stars’ light blends together.

By developing detailed models of close-star systems, Konacki was able to tease apart the tangled starlight. This allowed him to pinpoint, for the first time, the tug of a planet on a star snuggled next to other stars. Of 20 systems examined so far, HD 188753, located 149 light-years away, was the only one found to harbor a planet.

Hot Jupiters are believed to form out of thick disks, or “doughnuts,” of material that swirl around the outer fringes of young stars. The disk material clumps together to form a solid core, then pulls gas onto it. Eventually, the gas giant drifts inward. The discovery of a world under three suns contradicts this scenario. HD 188753 would have sported a truncated disk in its youth, due to the disruptive presence of its stellar companions. That leaves no room for HD 188753’s planet to form, and raises a host of new questions.

The masses of the three stars in HD 188753 system range from two-thirds to about the same mass as our Sun. The planet is slightly more massive than Jupiter.

For artist’s concepts and other graphics, visit http://planetquest.jpl.nasa.gov/ . For information about NASA and agency programs on the Web, visit http://www.nasa.gov/home/index.html .

Original Source: NASA News Release

Posted on by Fraser Cain

Superwinds Seen in Distant Galaxies

An artist’s impression of a Superwind in a young massive galaxy. Image credit: PPARC/David Hardy. Click to enlarge
A team of astronomers, led by the University of Durham, has discovered the aftermath of a spectacular explosion in a galaxy 11.5 billion light years away. Their observations, reported today (14th July 2005) in the journal Nature provide the most direct evidence yet of a galaxy being almost torn apart by explosions that produce a stream of high-speed material known as “Superwinds”. The observations were made using the 4.2 metre William Herschel Telescope on La Palma in which the UK is a major stakeholder.

Through Superwinds, galaxies are thought to blast a significant part of their gas into intergalactic space at speeds of up to several hundred miles per second. The driving force behind them is the explosion of many massive stars during an intense burst of star formation early in the galaxy’s life, possibly assisted by energy from a super massive black hole growing at its heart.

Superwinds are vital to the theory of galaxy formation for several reasons: firstly, they limit the sizes of galaxies by preventing further star formation – without them theoretical models indicate far more very bright galaxies than are actually seen in the Universe today. Secondly, they carry heavy elements – Star dust – far from their production sites in stars out into intergalactic space, providing raw material for planets and life across the Universe. Whilst the theories predicted Superwinds of this kind existed, previously observed examples were much smaller phenomena in nearby galaxies. These observations provide some of the most direct evidence yet for the existence of large-scale, galaxy-wide superwinds so far back in the history of the Universe.

The discovery of the Superwind was made by observing the gas in the halo of a galaxy (known as “LAB-2”), which at over 300,000 light years across is about three times larger than the disk of our own Milky Way galaxy. The astronomers discovered that light from hot glowing hydrogen gas is dimmed in a very specific way across the entire galaxy.

“We believe that the dimming is caused by a shell of cooled material which has been swept-up from the surroundings by a galaxy-wide Superwind explosion,” said Dr. Richard Wilman of the University of Durham. “Based on the uniformity of the absorption across the galaxy, it appears that the explosion was triggered several hundred million years earlier. This allows time for the gas to cool and to slow down from its high ejection speed, and thus to produce the absorption. As we see it, the shell is probably a few hundred thousand light years in front of its parent galaxy,” added Dr. Wilman.

Astronomers have long been puzzled about why key elements for the formation of planets and ultimately life (such as carbon, oxygen and iron) are so widely distributed throughout the Universe; only 2 billion years after the Big Bang, the remotest regions of intergalactic space have been enriched with them. The Superwind observed in this galaxy shows how such blast waves can travel through space carrying the elements formed deep within galaxies.

Crucial to the discovery and its interpretation was the ability to obtain detailed information on the gas in two-dimensions across the whole galaxy. This was made possible by a technique known as integral field spectroscopy, which is only just reaching maturity on the world’s largest telescopes.

Dr Joris Gerssen, a key member of the Durham team, explains, “Most astronomical spectroscopy is performed by placing a small aperture, or a narrow slit on the target, which for complex, extended sources such as this galaxy gives a rather incomplete picture”.

To overcome this the astronomers used an integral field spectrograph called ‘Sauron’ for a large survey of nearby galaxies, built at the Observatoire de Lyon by a collaboration of French, Dutch and UK astronomers.

Dr Gerssen added,” “Sauron is truly unique and its high efficiency means that it can more than hold its own against instruments on the world’s largest telescopes, some twice the size of the William Herschel Telescope. Nevertheless, the sheer distance of our target galaxy meant that Sauron had to stare at it for over 15 hours in order to make this discovery”.

“Sauron has provided us with the best evidence so far for an extensive outflow from a galaxy undergoing a huge starburst. These measurements are among the first steps towards understanding the physics of galaxy formation.,” commented Prof. Roger Davies, University of Oxford, one of the institutes involved on Sauron,” and we look forward to using similar two-dimensional spectrographs being built for 8m telescopes; these will probe the galaxy formation process to even earlier times.”

To date, observational evidence for Superwinds in young galaxies in the distant Universe has been largely indirect and circumstantial; efforts have focussed on searching for their subtle statistical signatures in large surveys of galaxies and intergalactic gas.

According to Prof. Richard Bower, from the University of Durham’s Institute of Computational Cosmology who initiated the research, “Astronomers have observed high-speed outflows in distant star-forming galaxies for several years, but never before have we been able to gauge their true scale from observations of a single galaxy. By taking advantage of the highly extended emission source of this galaxy, we can see the outflow as a kind of silhouette against the whole galaxy. This suggests that Superwinds are truly galaxy-wide in scale, and that they really are as important as our theories require.”

Original Source: PPARC News Release

Posted on by Fraser Cain

Malfunctioning Fuel Gauge Delays Shuttle

The Space Shuttle sits on the Mobile Launcher Platform (MLP). Image credit: NASA/KSC. Click to enlarge
The launch of NASA’s Space Shuttle Return to Flight mission, STS-114, will take place no earlier than Saturday, July 16 at 2:40 p.m. EDT. Space Shuttle Discovery’s liftoff today from NASA’s Kennedy Space Center, Fla., was postponed at 1:30 p.m. EDT.

During countdown activities, a low-level fuel cut-off sensor located inside the External Tank failed a routine prelaunch check. The sensor protects a Shuttle’s main engines by triggering their shut down in the event fuel runs unexpectedly low. The sensor is one of four inside the liquid hydrogen section of the External Tank.

The External Tank’s liquid oxygen and liquid hydrogen were drained this evening. While the tank was being emptied, engineers monitored and collected data on the liquid hydrogen sensor that failed. They will continue to collect and analyze data overnight.

Space Shuttle Program managers plan a series of meetings tomorrow to discuss the problem and determine the steps necessary to get back into the launch countdown.

The STS-114 crew will remain at Kennedy Space Center for now while engineers work on the problem.

During their 12-day Return to Flight mission to the International Space Station, Discovery’s seven crew members will test new techniques and equipment designed to make Space Shuttles safer. They’ll also deliver supplies and make repairs to the Space Station.

For the latest information about the STS-114 mission, visit:
http://www.nasa.gov/returntoflight

Original Source: NASA News Release

Posted on by Fraser Cain

Cluster Spacecraft Give Each Other Some Room

An artist’s impression of the Cluster quartet. Image credit: ESA. Click to enlarge
The four spacecraft of ESA?s Cluster fleet have reached their greatest distance from each other in the course of their mission to study Earth?s magnetosphere in three dimensions.

This operation, marking the fifth anniversary of Cluster in space, transforms Cluster in the first ?multi-scale? mission ever.
In one of the most complex manoeuvres ever conducted by ESA spacecraft, three of the spacecraft were separated to 10 000 kilometres from each other, with the fourth spacecraft at 1000 kilometres from the third one.

This new fleet formation for Cluster was achieved in two months of operations. The repositioning of the satellites was started by mission controllers at ESA’s European Space Operations Centre (ESOC), in Darmstadt, Germany, on 26 May, and was run until 14 July.

During the course of the mission, the distance between the Cluster satellites had already changed five times, in a range between 100 and 5000 kilometres. Varying the size – but not the shape – of the Cluster ?constellation? had allowed Cluster to examine Earth?s magnetosphere at different scales.

But now this new ?asymmetric? flying formation is allowing the Cluster spacecraft to make measurements of medium- and large-scale phenomena simultaneously, transforming Cluster in the first ever ?multi-scale? mission.

With this, it is possible to study at the same time the link between small-scale kinetic processes of the plasma around Earth and the large-scale morphology of the magnetosphere.

The knowledge gained by Cluster about the magnetosphere ? the natural magnetic shield that surrounds and protects our planet ? has already helped advance our understanding of how the solar wind affects Earth?s natural space environment.

This is also important in our daily life as, for instance, intense solar activity can disrupt terrestrial communication networks, power grids and data lines.

Original Source: ESA Portal

Posted on by Fraser Cain

Will We Find Super Earths?


An extrasolar planet with hypothetical (possible but unproven) water-bearing moons. Image credit: NASA/IPAC/R. Hurt. Click to enlarge
Over the past decade, astronomers using a planet-hunting technique that measures small changes in a star’s speed relative to Earth, have discovered more than 130 extrasolar planets. The first such planets were gas giants, the mass of Jupiter or larger. After several years, the scientists began to detect Saturn-mass planets. And last August, they announced the discovery of a handful of Neptune-mass planets. Could these be super-Earths?

In a recent talk at a symposium on extrasolar planets, Carnegie Institution of Washington astronomer Alan Boss explained the possibilities.

Radial-velocity planet-hunting techniques recently have pushed our discovery capability below the Saturn-mass limit down into what we would call the ice-giant limit.

So we are now able to find planets, close to their host stars, with masses comparable to that of Uranus and Neptune (14 to 17 times the mass of Earth).

In large part this is due to Michel Mayor and his colleagues having a new spectrometer in La Silla, which has unprecedented spectral resolution down to about 1 meter per second or so. And I think Geoff Marcy and Paul Butler’s group are quite close behind that as well.

The interesting question, though, is: What are these things? Are they ice giants that formed several AUs out and migrated in, or are they something else? Unfortunately, we don’t know exactly what their masses are. Even more importantly, we don’t really know what their density is. So they could be 15-Earth-mass rocks, or they could be 15-Earth-mass ice giants.

What we really need to do is to have folks go out and discover another 7 or so. We’ve got 3 so far. If we had 10 altogether, then we’ll have enough that 1 of them, at least, should transit its star and then we’ll be able to get some idea of what its density is.

I think, though, that there’s a good chance that these might actually be a new class of planet altogether: super-Earths. The reason I would argue that is that, at least in 2 of the systems where they’ve been found, these “hot Neptunes” are accompanied by a larger Jupiter-mass planet with a longer-period orbit.

If the lower-mass planets are ice giants that formed far from their stars, unless you have some highly contrived scenario, you wouldn’t imagine them to end up migrating inward, past the larger guys. These systems look more like our own solar system, where you have the low-mass fellows inside of the gas giants.

The planets in a system like our system presumably did not undergo very much migration. So I would claim that perhaps these guys are objects which formed inside the gas giants and only migrated in a little bit, ending up where we can detect them with the short-period spectroscopy surveys.

In support of this idea, there’s some theoretical work from Carnegie’s George Wetherill from almost 10 years ago, now, where he had done some calculations of the accumulation process of rocky planets. He often found there was quite a spread in the masses of what you got out, because accumulation’s a very stochastic process. For the typical parameters he used, at the end of 100 million years or so, he would not only get objects of 1 Earth mass, but also objects ranging up to 3 Earth masses.

Well, at the time, he assumed for his calculations a fairly low surface density at 1 AU, where these planets were forming. Given what we know now, if you want to be able to make a Jupiter at 5 AU using the core-accretion model of planetary formation, you have to crank up the density in the protoplanetary disk by a factor of 7 or so over what Wetherill assumed.

That scales directly with the mass of the planets you’d expect to find as a result. So if you did these calculations over again, assuming this higher initial density, the upper limit on the mass of the inner planets would go from 3 Earth masses, which is what Wetherill got, up to say 21 Earth masses. That is in the range of what we are estimating for these newly discovered hot Neptune-mass objects.

So perhaps what we really are seeing is a new class of objects, super-Earths, rather than ice giants.

Original Source: NASA Astrobiology

Posted on by Fraser Cain

Three Space Telescopes Find a Neutron Star

Artist’s impression of neutron star IGR J16283-4838. Image Credit:NASA/Dana Berry. Click to enlarge
An international team of scientists has uncovered a rare type of neutron star so elusive that it took three satellites to identify it.

The findings, made with ESA?s Integral satellite and two NASA satellites, reveals new insights about star birth and death in our Galaxy. We report this discovery, highlighting the complementary nature of European and US spacecraft, on the day in which ESA?s Integral celebrates 1000 days in orbit.
The neutron star, called IGR J16283-4838, is an ultra-dense ?ember? of an exploded star and was first seen by Integral on 7 April 2005. This neutron star is about 20,000 light years away, in a ?double hiding place?. This means it is deep inside the spiral arm Norma of our Milky Way galaxy, obscured by dust, and then buried in a two-star system enshrouded by dense gas.

?We are always hunting for new sources,? said Simona Soldi, the scientist at the Integral Science Data Centre in Geneva, Switzerland, who first saw the neutron star. ?It is exciting to find something so elusive. How many more sources like this are out there??

Neutron stars are the core remains of ?supernovae?, exploded stars once about ten times as massive as our Sun. They contain about a Sun’s worth of mass compacted into a sphere about 20 kilometres across.

?Our Galaxy?s spiral arms are loaded with neutron stars, black holes and other exotic objects, but the problem is that the spiral arms are too dusty to see through,? said Dr Volker Beckmann at NASA Goddard Spaceflight Centre, lead author of the combined results.

?The right combination of X-ray and gamma-ray telescopes could reveal what is hiding there, and provide new clues about the true star formation rate in our Galaxy,? he added.

Because gamma rays are hard to focus into sharp images, the science team then used the X-ray telescope on Swift to determine a precise location. In mid April 2005, Swift confirmed that the light was ?highly absorbed?, which means the binary system was filled with dense gas from the stellar wind of the companion star.

Later the scientists used the Rossi Explorer to observe the source as it faded away. This observation revealed a familiar light signature, clinching the case for a fading high-mass X-ray binary with a neutron star.

IGR J16283-4838 is the seventh so-called ?highly absorbed?, or hidden neutron star to be identified. Neutron stars, created from fast-burning massive stars, are intrinsically tied to star formation rates. They are also energetic ?beacons? in regions too dusty to study in detail otherwise. As more and more are discovered, new insights about what is happening in the Galaxy’s spiral arms begin to emerge.

IGR J16283-4838 revealed itself with an ?outburst? on or near its surface. Neutron stars such as IGR J16283-4838 are often part of binary systems, orbiting a normal star. Occasionally, gas from the normal star, lured by gravity, crashes onto the surface of the neutron star and releases a great amount of energy. These outbursts can last for weeks before the system returns to dormancy for months or years.

Integral, the Rossi Explorer and Swift all detect X-rays and gamma rays, which are far more energetic than the visible light that our eyes detect. Yet each satellite has different capabilities. Integral has a large field of view, enabling it to scan our Milky Way galaxy for neutron stars and black hole activity.

Swift contains a high-resolution X-ray telescope, which allowed scientists to zoom in on IGR J16283-4838. The Rossi Explorer has a timing spectrometer, a device used to uncover properties of the light source, such as speed and rapid variations in the order of milliseconds.

Original Source: ESA Portal

Posted on by Fraser Cain

Prometheus Shepherding the Rings

Saturn’s shepherd moon Prometheus hovers between the A and F rings. Image credit; NASA/JPL/SSI. Click to enlarge
Saturn’s shepherd moon Prometheus hovers between the A and F rings as if suspended on an invisible thread, while bright clouds drift in Saturn’s atmosphere approximately 130,000 kilometers (81,000 miles) beyond. It is noteworthy that such clouds are visible here in the shadows cast by the rings. Prometheus is 102 kilometers (63 miles) across.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 3, 2005, at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. The image scale is 13 kilometers (8 miles) per pixel. This view was processed to enhance fine details.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org.

Original Source: NASA/JPL/SSI News Release

Posted on by Fraser Cain

Supercomputer Will Study Galaxy Evolution

This view of nearly 10,000 galaxies is the deepest visible-light image of the cosmos. Image credit: Hubble. Click to enlarge
One of the fastest supercomputers in the world and the first ever designed specifically to study the evolution of star clusters and galaxies is now in operation at Rochester Institute of Technology.

The new computer, built by David Merritt, professor of physics in RIT?s College of Science, uses a novel architecture to reach speeds much higher than that of standard supercomputers of comparable size.

Known as gravitySimulator, the computer is designed to solve the ?gravitational N-body problem?. It simulates how a galaxy evolves as the stars move about each other in response to their own gravity. This problem is computationally demanding because there are so many interactions to calculate requiring a tremendous amount of computer time. As a result, standard supercomputers can only carry out such calculations with thousands of stars at a time.

The new computer achieves much greater performance by incorporating special accelerator boards, called GRAPEs or Gravity Pipelines, into a standard Beowulf-like cluster. The gravitySimulator, which is one of only two machines of its kind in the world, achieves a top speed of 4 Teraflops, or four trillion calculations per second, making it one of the 100 fastest computers in the world, and it can handle up to 4 million stars at once. The computer cost over $500,000 to construct and was funded by RIT, the National Science Foundation, and NASA.

Since gravitySimulator was installed in the spring, Merritt and his associates have been using it to study the binary black hole problem- what happens when two galaxies collide and their central, supermassive black holes form a bound pair.

?Eventually the two black holes are expected to merge into a single, larger black hole,? Merritt says. ?But before that happens, they interact with the stars around them, ejecting some and swallowing others. We think we see the imprints of this process in nearby galaxies, but so far no one has carried out simulations with high enough precision to test the theory.?

Merritt and his team will also use gravitySimulator to study the dynamics of the central Milky Way Galaxy in order to understand the origin of our own black hole.

Merritt sees the gravitySimulator as an important example of RIT?s development as a major scientific research institute. ?Our unique combination of in-class instruction, experiential learning and research will be a major asset in the continued development of astrophysics and other research disciplines here at RIT,? Merritt says. ?The gravitySimulator is the perfect example of the cutting edge work we are already doing and will be a major stepping stone for the development of future scientific research.?

Original Source: RIT News Release

Posted on by Fraser Cain

Sloan Digital Sky Survey, Part II

NGC 5919 is a member of a galaxy cluster Abel 2063. Image credit: SDSS. Click to enlarge.
Dr. Richard Kron, director of the Sloan Digital Sky Survey, announced a new undertaking that will complete the largest survey of the universe. This survey will add new partners and undertake new research missions, and will run through summer 2008.

Late last month the funding package for a new, three-year venture called the Sloan Digital Sky Survey II (SDSS-II) was completed, led by the Alfred P. Sloan Foundation of New York City, the National Science Foundation (NSF), the U.S. Department of Energy and the member institutions.

The SDSS has been carrying out a massive survey of the sky using a dedicated 2.5-m telescope at Apache Point Observatory near Sunspot, New Mexico. SDSS-II will complete observations of a huge contiguous region of the Northern skies and will study the structure and origins of the Milky Way Galaxy and the nature of dark energy.

The Sloan Digital Sky Survey is the most ambitious astronomical survey project ever undertaken, already having measured precise brightnesses and positions for hundreds of millions of galaxies, stars and quasars during the last five years. The consortium of more than 300 scientists and engineers at 23 institutions around the world — and hundreds of other scientists working in collaboration — are using these data to address fascinating and fundamental questions about the universe.

The exciting results from the SDSS data to date include the discovery of distant quasars seen when the universe was just 900 million years old; the definitive measurement of the large-scale distribution of galaxies, confirming the role of gravity in growing structures in the universe; and evidence that the Milky Way Galaxy grew by cannibalizing smaller companion galaxies.

“We are very excited with the funding agencies’ decision to support this important mission,” said Kron of the University of Chicago. “The dedicated scientists and engineers of the Sloan Digital Sky Survey have worked tirelessly to open new ways of seeing the Universe.

“We believe the SDSS II discoveries that lie ahead will further scientific discoveries and lay the groundwork for future astronomical exploration. We are sure that the data released to the public will yield discoveries for years to come.”

In the last five years, the SDSS has released data for almost 200 million objects to the public. These data have been used by hundreds of researchers around the world for scientific projects ranging from studies of nearby stars to explorations of the nature of galaxies.

“We are proud of the landmark contributions made by the Sloan Digital Sky Survey to our understanding of the evolution and structure of the universe and enthusiastically support this next phase of research,” said Doron Weber, program director of the Alfred P. Sloan Foundation. “The findings of the Sloan Digital Sky Survey have already produced the most accurate picture of the skies that has ever existed and we expect new discoveries that will continue to transform our knowledge of the universe.”

Eileen D. Friel, Executive Officer of the Division of Astronomical Sciences at the National Science Foundation, said the Sloan Digital Sky Survey “has enabled a remarkable array of scientific results, sometimes in unexpected areas. The completion of the original survey and its extension to address issues in galactic and stellar astronomy promises to strengthen the legacy of the survey and to make it an even more valuable resource for astronomers and educators.”

And Robin Staffin, Associate Director of Science for High Energy Physics in the Department of Energy’s Office of Science, said the agency was “delighted to see the Sloan Digital Sky Survey entering this new phase. SDSS has already contributed a great deal to our understanding of the fundamental structure of the universe, and has helped pioneer the connections between particle physics and cosmology. We expect that great science will come out of SDSS-II over the next few years.”

With the formation of SDSS-II, eight new institutions join the collaboration: American Museum of Natural History in New York City, the University of Basel (Switzerland), Cambridge University (UK), Case Western Reserve University in Cleveland, Ohio, the Joint Institute for Nuclear Astrophysics (University of Notre Dame, Michigan State University, and The University of Chicago), The Kavli Institute for Particle Astrophysics and Cosmology at Stanford, Ohio State University, and the Astrophysical Institute Potsdam (Germany). (A complete list of SDSS-I and SDSS-II partners can be found below).

SDSS-II has three components. The first, called LEGACY, will complete the SDSS survey of the extragalactic universe, obtaining images and distances of nearly a million galaxies and quasars over a continuous swath of sky in the Northern Hemisphere.

The new funding also inaugurates the second part of SDSS-II, the Sloan Extension for Galactic Understanding and Exploration (SEGUE), mapping the structure and stellar makeup of the Milky Way Galaxy, and gathering data on how the Milky Way formed and evolved.

“The SEGUE project will allow us for the first time to get a ‘big picture’ of the structure of our own Milky Way,” explained consortium member Heidi Newberg of Rensselaer Polytechnic Institute. “The mapping of the Milky Way is more than an exercise in cartography. Ages, chemical compositions, and space distribution of stars are major clues to understanding how our own Galaxy formed, and, by example, how galaxies, in general. formed.

“Identifying the oldest stars will help us understand how the elements of the periodic table were formed long ago inside of stars,” Newberg said.

The final piece of SDSS-II includes an intensive study of supernovae, sweeping the sky to find these remnants of gigantic explosions from dying stars. Astronomers can precisely measure the distances of distant supernovae, using them to map the rate of expansion of the universe.

“This study will help to verify and quantify one of the most important discoveries of modern science – the existence of the cosmological dark energy,” explained consortium member Andy Becker of the University of Washington.

Becker explained that the SDSS telescope is uniquely positioned to both discover, and follow up on, a wealth of supernovae at distances at which other surveys have found very few objects. This allows a direct measurement of the effects of dark energy on the geometry of the universe as a whole.

Original Source: SDSS News Release