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A new ruler available to measure the universe

LAWRENCE BERKELEY NATIONAL LABORATORY NEWS RELEASE
Posted: May 22, 2006

A team of astronomers led by Nikhil Padmanabhan and David Schlegel has published the largest three-dimensional map of the universe ever constructed, a wedge-shaped slice of the cosmos that spans a tenth of the northern sky, encompasses 600,000 uniquely luminous red galaxies, and extends 5.6 billion light-years deep into space, equivalent to 40 percent of the way back in time to the Big Bang.



A schematic view of the new SDSS three-dimensional map,
which includes regular galaxies (black points) and luminous red
galaxies (red points) and extends 5.6 billion light-years, 40
percent of the distance to the edge of the visible universe. Credit:
LBNL
 


Schlegel is a Divisional Fellow in the Physics Division of Lawrence Berkeley National Laboratory, and Padmanabhan will join the Lab's Physics Division as a Chamberlain Fellow and Hubble Fellow in September; presently he is at Princeton University. They and their coauthors are members of the Sloan Digital Sky Survey (SDSS), and have previously produced smaller 3-D maps by using the SDSS telescope in New Mexico to painstakingly collect the spectra of individual galaxies and calculate their distances by measuring their redshifts.

"What's new about this map is that it's the largest ever," says Padmanabhan, "and it doesn't depend on individual spectra."

The principal motive for creating large-scale 3-D maps is to understand how matter is distributed in the universe, says Padmanabhan. "The brightest galaxies are like lighthouses -- where the light is, is where the matter is."

Schlegel says that "because this map covers much larger distances than previous maps, it allows us to measure structures as big as a billion light-years across."

A natural ruler in space


The variations in galactic distribution that constitute visible large-scale structures are directly descended from variations in the temperature of the cosmic microwave background, reflecting oscillations in the dense early universe that have been measured to great accuracy by balloon-borne experiments and the WMAP satellite.

The result is a natural "ruler" formed by the regular variations (sometimes called "baryon oscillations," with baryons as shorthand for ordinary matter), which repeat at intervals of some 450 million light-years.

"Unfortunately it's an inconveniently sized ruler," says Schlegel. "We had to sample a huge volume of the universe just to fit the ruler inside."

Says Padmanabhan, "Although the universe is 13.7 billion years old, that really isn't a whole lot of time when you're measuring with a ruler that's marked only every 450 million light-years."

The distribution of galaxies reveals many things, but one of the most important is a measure of the mysterious dark energy that accounts for some three-fourths of the universe's density. (Dark matter accounts for roughly another 20 percent, while less than 5 percent is ordinary matter of the kind that makes visible galaxies.)

"Dark energy is just the term we use for our observation that the expansion of the universe is accelerating," Padmanabhan remarks. "By looking at where density variations were at the time of the cosmic microwave background" -- only about 300,000 years after the Big Bang -- "and seeing how they evolve into a map that covers the last 5.6 billion years, we can see if our estimates of dark energy are correct."

The new map shows that the large-scale structures are indeed distributed the way current ideas about the accelerating expansion of the universe would suggest. The map's assumed distribution of dark matter, which although invisible is affected by gravity just like ordinary matter, also conforms to current understanding.

Dead, red galaxies

What made the big new 3-D map possible were the Sloan Digital Sky Survey's wide-field telescope, which covers a three-degree field of view (the full moon is about half a degree), plus the choice of a particular kind of galactic "lighthouse," or distance marker: luminous red galaxies.

"These are dead, red galaxies, some of the oldest in the universe -- in which all the fast-burning stars have long ago burned out and only old red stars are left," says Schlegel. "Not only are these the reddest galaxies, they're also the brightest, visible at great distances."

The Sloan Digital Sky Survey astronomers worked with colleagues on the Australian Two-Degree Field team to average the color and redshift of a sample of 10,000 red luminous galaxies, relating galaxy color to distance. They then applied these measurements to 600,000 such galaxies to plot their map.

Padmanabhan concedes that "there's statistical uncertainty in applying a brightness-distance relation derived from 10,000 red luminous galaxies to all 600,000 without measuring them individually. The game we play is, we have so many that the averages still give us very useful information about their distribution. And without having to measure their spectra, we can look much deeper into space."

Schlegel agrees that the researchers are far from achieving the precision they want. "But we have shown that such measurements are possible, and we have established the starting point for a standard ruler of the evolving universe."

He says "the next step is to design a precision experiment, perhaps based on modifications to the SDSS telescope. We are working with engineers here at Berkeley Lab to redesign the telescope to do what we want to do."

"The Clustering of Luminous Red Galaxies in the Sloan Digital Sky Survey Imaging Data," by Nikhil Padmanabhan, David J. Schlegel, Uros Seljak, Alexey Makarov, Neta A. Bahcall, Michael R. Blanton, Jonathan Brinkmann, Daniel J. Eisenstein, Douglas P. Finkbeiner, James E. Gunn, David W. Hogg, Zeljko Ivezic', Gillian R. Knapp, Jon Loveday, Robert H. Lupton, Robert C. Nichol, Donald P. Schneider, Michael A. Strauss, Max Tegmark, and Donald G. York, will appear in the Monthly Notices of the Royal Astronomical Society

SOURCE: SPACEFLIGHTNOW.COM


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Underwater Hotel

Currently under construction in Dubai, Hydropolis is the world's
first underwater luxury hotel. It will include three elements: the
land station, where guests will be welcomed, the connecting tunnel,
which will transport people by train to the main area of the hotel,
and the 220 suites within the submarine leisure complex.

This will be a hotel where those who do not dive - or do not even
swim - can experience the tranquillity and inspiration of the
underwater world.




In order to enter this surreal space, visitors will begin at the
 land station. This 120m woven, semicircular cylinder will arch over
a multi-storey building.






The upper storeys of the land station house a variety of facilities,
including a cosmetic surgical clinic, a marine biological research
laboratory and conference facilities.




The world of science fiction becoming reality.





SOURCE: http://www.alltraveltips.com/underwaterhotel.html



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Crunch time for Planet Pluto  
By Nicola Cook
BBC Horizon  



Pluto moves from 30 to 50 times the Sun-Earth distance over its 248-
year orbit. It has two moons in addition to Charon (the smaller
object pictured here). The gravity on Pluto is about 6% of Earth's;
the surface temperature -233C.



 
At its conference this August, the International Astronomical Union (IAU) will make a decision that could see Pluto lose its status as a planet.

For the first time, the organisation will be officially defining the word "planet", and it is causing much debate in the world of astronomy.

There is only one thing that everyone seems to agree on: there are no longer nine planets in the Solar System.

Matters were brought to a head by the discovery in January of last year of a potential 10th planet, temporarily named 2003 UB313.

Professor Mike Brown and his team at the California Institute of Technology have already discovered several large objects on the edge of the Solar System, but 2003 UB313 is special because it is bigger than Pluto.

The question now facing the IAU is whether to make this new discovery a planet.

Pressing issue

Co-discoverer Dr Chad Trujillo thinks the solution is pretty straightforward.

"The logically consistent thing would be to either have 2003 UB313 a planet, and Pluto be a planet; or have neither be a planet," he told the BBC's Horizon programme.

But Pluto is already an unusual planet. It is made predominantly of ice, and is smaller even than the Earth's Moon.

 



In 1992, Professor Dave Jewitt and Dr Jane Lu at the University of Hawaii discovered a new collection of objects beyond Neptune called the Kuiper Belt. Some suggest Pluto should no longer be considered a planet, but a Kuiper Belt Object.

As Professor Jewitt says: "We always say we found plus one Kuiper Belt, and minus one planet. And the one we lost, of course, is Pluto."

There are many astronomers who agree with Dave Jewitt and would opt for an eight-planet Solar System, with neither Pluto or 2003 UB313 making the grade; but a number of astronomers are arguing for a more specific definition of a planet.

Kuiper Belt researcher Dr Marc Buie, of the Lowell Observatory in Arizona, has come up with a clear planetary definition he would like to see the IAU adopt.

Different categories

"I believe the definition of planet should be as simple as possible, so I've come up with two criteria," he said.

"One is that it can't be big enough to burn its own matter - that's what a star does. On the small end, I think the boundary between a planet and not a planet should be, is the gravity of the object stronger than the strength of the material of the object? That's a fancy way of saying is it round?"

 

This definition could lead to a Solar System with as many as 20 planets, including Pluto, 2003 UB313, and many objects previously classified as moons or asteroids.

One possible resolution to the debate is for new categories of planet to be introduced. Mercury, Venus, the Earth and Mars would be "rocky planets". The gas-giants Jupiter, Saturn, Uranus and Neptune would be a second category.

Pluto, 2003 UB313, and any other objects passing the "roundness test", would be reclassified as a third type of planet - perhaps "icy dwarfs".

Whatever the final outcome, by September there will no longer be nine planets in the Solar System.



Bye-Bye Planet Pluto is broadcast on BBC Two at 2100 BST this Thursday, 22 June
 



SOURCE: BBC.CO.UK

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Hubble reveals two dust disks around nearby star
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: June 28, 2006

Detailed images of the nearby star Beta Pictoris, taken by NASA's Hubble Space Telescope, confirm the existence of not one but two dust disks encircling the star. The images offer tantalizing new evidence for at least one Jupiter-size planet orbiting Beta Pictoris.



Larger versionHERE


The finding ends a decade of speculation that an odd warp in the young star's debris disk may actually be another inclined disk. The recent Hubble Advanced Camera for Surveys view ­ the best visible-light image of Beta Pictoris ­ clearly shows a distinct secondary disk that is tilted by about 4 degrees from the main disk. The secondary disk is visible out to roughly 24 billion miles from the star, and probably extends even farther, said astronomers.

The finding, by a team of astronomers led by David Golimowski of Johns Hopkins University in Baltimore, Md., appears in the June 2006 issue of the Astronomical Journal. To see the faint disk, astronomers used the Advanced Camera for Surveys' coronagraph, which blocked the light from Beta Pictoris. The disk is fainter than the star because its dust only reflects light.

The best explanation for the observations is that a suspected unseen planet, about one to 20 times the mass of Jupiter and in an orbit within the secondary disk, is using gravity to sweep up material from the primary disk.

"The Hubble observation shows that it is not simply a warp but two concentrations of dust in two separate disks," Golimowski said. "The finding suggests that planetary systems could be forming in two different planes. We know this can happen because the planets in our solar system are typically inclined to Earth's orbit by several degrees. Perhaps stars forming more than one dust disk may be the norm in the formative years of a star system."

Dynamical computer models by David Mouillet and Jean-Charles Augereau of Grenoble Observatory in France suggest how a secondary dust disk can form. A planet in an inclined orbit gravitationally attracts small bodies of rock and/or ice, called planetesimals, from the main disk, and moves them into an orbit aligned with that of the planet. These perturbed planetesimals then collide with each other, producing the tilted dust disk seen in the new Hubble images.

Astronomers do not know how the planet, if it exists, settled into an inclined orbit. However, computer simulations by multiple research teams show that planet embryos which start out in a very thin plane, can, through gravitation interactions, rapidly scatter into orbits that become inclined to the primary disk. Whatever the process, the four degree inclination of the suspected perturbing planet in Beta Pictoris is not unlike the several degree spread seen in our solar system.

"The actual lifetime of a dust grain is relatively short, maybe a few hundred thousand years," Golimowski explained. "So the fact that we can still see these disks around a 10- to 20-million-year-old star means that the dust is being replenished by collisions between planetesimals."

Beta Pictoris is located 63 light-years away in the southern constellation Pictor. Although the star is much younger than the Sun, it is twice as massive and nine times more luminous. Beta Pictoris entered the limelight over 20 years ago when NASA's Infrared Astronomical Satellite detected excess infrared radiation from the star. Astronomers attributed this excess to the presence of warm circumstellar dust.

The dust disk was first imaged by ground-based telescopes in 1984. Those images showed that the disk is seen nearly edge-on from Earth. Hubble observations in 1995 revealed an apparent warp in the disk.

Subsequent images obtained in 2000 by Hubble's Space Telescope Imaging Spectrograph confirmed the warp. The latter study was led by Sara Heap of NASA's Goddard Space Flight Center in Greenbelt, Md. At that time, Heap and her colleagues suggested that the warp may be a secondary disk tilted about 4 degrees from the main disk. Several teams of astronomers attributed the warp to a planet in a tilted orbit out of the plane of the main disk.

Astronomers using ground-based telescopes also found various asymmetries in the star's disk. Infrared images taken in 2002 by the Keck II Observatory in Hawaii showed that another, smaller inner disk may exist around the star in a region the size of our solar system. Golimowski's team did not spot the disk because it is small and is blocked by the Advanced Camera's coronagraph. This possible inner disk is tilted in the opposite direction from the disk seen in the new Hubble images. This misalignment implies that the tilted disks are not directly related. Nevertheless, they both may bolster evidence for the existence of one or more planets orbiting the star.

SOURCE: SPACEFLIGHTNOW.COM



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FSU Etruscan expert announces historic discovery at ancient site

Tallahassee, Fla. -- Digging on a remote hilltop in Italy, a Florida State University classics professor and her students have unearthed artifacts that dramatically reshape our knowledge of the religious practices of an ancient people, the Etruscans.




View of the Etruscan site at Cetamura, with a rock platform hypothesized to be an Etruscan altar of the second century BCE.




"We are excavating a monumental Etruscan building evidently dating to the final years of Etruscan civilization," said Nancy Thomson de Grummond, the M. Lynette Thompson Professor of Classics at FSU and director of the university's archaeology programs in Italy. Within the building, de Grummond's team located in early June what appears to be a sacrificial pit and a sanctuary -- finds remarkable for the wealth of items they are yielding that appear to have been used in religious rituals.

Nearly every summer since 1983, de Grummond has taken groups of FSU students into Italy's Tuscany region to participate in archaeological digs at Cetamura del Chianti, a site once inhabited by the Etruscans and ancient Romans. In the final days of this year's program, de Grummond and her students unearthed what she calls "the most thrilling" find she has seen in 23 years at Cetamura.

She explained that the Etruscans, who once ruled most of the Italian peninsula, were conquered and absorbed by the Romans in the second and first centuries B.C.E. ("Before the Common Era"). Prior to that time, however, they were a highly advanced civilization that constructed roads, buildings and sewer systems and developed the first true cities in Europe. They also built large, complex religious sanctuaries -- which may have been the purpose served, in part, by the Cetamura structure.

"The building has a highly irregular plan, with stone foundations 3 or 4 feet thick," she said. "One wing of the building is about 60 feet long, flanking a space that has walls running at right angles. Some walls run on a diagonal to the grid, or are curved. There are paved areas alternating with beaten earth floors and what I believe to be a large courtyard in the middle. Some of the foundations are so heavy and thick that they could easily have supported multistoried elements.


Etruscan potsherd with an incised inscription with the name of the god Lurs, worshipped at Cetamura.


Within the building's courtyard, de Grummond said, is a freestanding sandstone platform that likely served as an altar. A few feet away, she and her students unearthed "the most fascinating find of all -- a pit filled with burnt offerings for the gods.

"In all, the pit contained approximately 10 vessels, some miniature and thus clearly intended only as gifts for the gods," de Grummond said. "On the other hand, several of the vessels were quite large, including one storage vessel, probably for grain, and a huge pitcher, probably for wine. There also were little cups for drinking and a bowl for eating, as well as a small beaker of the type that holds oil or spices. All of these vessels were ceramic, some ritually broken and but with most or all of the fragments buried together in the pit. Further, most of the pots seem to be locally made rather than imported. They were offering to the gods their own special creations.

"We should be able to restore these vases and have quite a splendid array of Etruscan pottery dating from a single moment and a particular place in their history," de Grummond said.

Also of great interest to de Grummond was the discovery of some 10 iron nails deposited in the pit, all in an excellent state of preservation.

"These reflect what we know from ancient texts in Latin that note that the Etruscans treated nails as sacred, and regarded them as symbolizing inexorable fate," she said. "They had a ritual practice in regard to their deity Nurtia in which they would hammer a nail into the wall of the temple each year as a tribute to the goddess. We cannot yet be sure about the cultic significance of the nails of Cetamura, but they may well relate to the passage of time and thus to the sacred calendar of the Etruscans."

One of de Grummond's students also unearthed an Etruscan inscription on a shard of pottery that contained the name of a little-known Etruscan god, Lurs.
.

"Almost nothing is known about Lurs, but we may have at Cetamura some very rare evidence about his worship," she said.

De Grummond is a leading scholar on the religious practices of the Etruscans, a people whose culture profoundly influenced the ancient Romans and Greeks. "The Religion of the Etruscans," a book written and edited by de Grummond and Erika Simon, another expert in classical archaeology who served as the Langford Family Eminent Scholar in Classics at FSU in 1999, was published last spring. De Grummond soon will release another book, "Etruscan Myth, Sacred History and Legend."

De Grummond said she hopes to continue excavating the Cetamura sacred area, and building on nearly a quarter-century of knowledge that she has gathered there.

"It is a bit eerie to have excavated something so central to my own lifelong interest in the myth, religion and rituals of the Etruscans," she said. "Without a doubt, this is one of the most exciting of the discoveries I have experienced."

SOURCE: EUREKAALERT.

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Now i know why they say "it's just the tip of the iceburg"lol..



k
 

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Cassini's radar mapper finds possible lakes on Titan
CASSINI PHOTO RELEASE





Want a bigger piccy ?..then click HERE

The Cassini spacecraft, using its radar system, has discovered very strong evidence for hydrocarbon lakes on Titan. Dark patches, which resemble terrestrial lakes, seem to be sprinkled all over the high latitudes surrounding Titan's north pole.

Scientists have speculated that liquid methane or ethane might form lakes on Titan, particularly near the somewhat colder polar regions. In the images, a variety of dark patches, some with channels leading in or out of them, appear. The channels have a shape that strongly implies they were carved by liquid. Some of the dark patches and connecting channels are completely black, that is, they reflect back essentially no radar signal, and hence must be extremely smooth. In some cases rims can be seen around the dark patches, suggesting deposits that might form as liquid evaporates. The abundant methane in Titan's atmosphere is stable as a liquid under Titan conditions, as is its abundant chemical product, ethane, but liquid water is not.

For all these reasons, scientists interpret the dark areas as lakes of liquid methane or ethane, making Titan the only body in the solar system besides Earth known to possess lakes. Because such lakes may wax and wane over time, and winds may alter the roughness of their surfaces. Repeat coverage of these areas should test whether indeed these are bodies of liquid.

These two radar images were acquired by the Cassini radar instrument in synthetic aperture mode on July 21, 2006. The top image centered near 80 degrees north, 92 degrees west measures about 420 kilometers by 150 kilometers (260 miles by 93 miles). The lower image centered near 78 degrees north, 18 degrees west measures about 475 kilometers by 150 kilometers (295 miles by 93 miles). Smallest details in this image are about 500 meters (1,640 feet) across.

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 was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.


SOURCE: SPACEFLIGHTNOW.COM

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Going out with a bang
Lunar orbiter to impact
BY STEPHEN CLARK
SPACEFLIGHT NOW


A pioneering space probe has set a course for a dramatic end to its three-year mission in September, when it will collide with the Moon in a spectacular send-off for scientists to learn new information about the lunar surface.


This artist's impression shows the trajectory of the SMART-1 spacecraft in the final phase of its mission. Credits: ESA

BIG PICCY right here

 
Going out with a bang
Lunar orbiter to impact
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: July 24, 2006

A pioneering space probe has set a course for a dramatic end to its three-year mission in September, when it will collide with the Moon in a spectacular send-off for scientists to learn new information about the lunar surface.


This artist's impression shows the trajectory of the SMART-1 spacecraft in the final phase of its mission. Credits: ESA
Download larger image version here
 
 
The innovative SMART-1 technology demonstrator is about to wrap up a highly successful mission testing a range of new spacecraft concepts and systems for potential use in the future. The Swedish-built craft also conducted a broad science program using an array of instruments.

The end will come with a fiery crash into the Moon's nearside at about 0541 GMT (1:41 a.m. EDT) on September 3, according to the best data now available. This time is only certain within seven hours.

The exact timing of the impact will slightly change as the probe's orbit evolves in several upcoming trim maneuvers designed to fine-tune the craft's approach. Five such burns are planned for July 27, July 28, August 25, and on the final two days before SMART-1 hits the surface.

Scientists' "best guess" on the impact site puts it in the Moon's mid-southern latitudes in a region known as the Lake of Excellence. The location is believed to be of mostly volcanic origin and areas of highlands and hills are also nearby. The area is also known as Lacus Excellentiae in Latin.

At the time of impact, the Lake of Excellence will be shrouded in darkness - only slightly illuminated by light from the Earth in a phenomenon called "earthshine." The boundary between bright sunshine and nighttime on the Moon will be located not far away, possibly allowing material blown above the surface to reach altitudes high enough to be lit by sunlight.

Ground controllers in Germany had to command a two-week series of thruster firings to raise the low point of SMART-1's trek around the Moon to push back the inevitable crash from about August 17 to the current date of September 3. The plan also brought the forecasted impact site into the direct view of scientists on the ground. If left undisturbed, the 630-pound probe would have smacked into the far side of the Moon facing away from Earth.

The set of orbit-raising maneuvers began June 19 and ended on July 2 - about five days ahead of schedule.

Astronomers at observatories across the globe plan to try to see the plume of debris ejected high above the lunar surface as SMART-1 drives into the Moon. Organized groups at the European Southern Observatory in Chile, Kitt Peak in Arizona, telescopes in Hawaii, and other locations will attempt to spot the impact and its aftermath

The most favorable position for observing an on-time impact will be in North and South America and Hawaii. There, the quarter Moon will be high in the sky for prime viewing.

Larger telescopes could detect a flash at the moment of impact due to vaporized hydrazine fuel. A few minutes later, dust and rocks thrown high above the Moon might be seen. If the debris reaches an altitude of over 12 miles, it could be lit by sunlight. If so, amateur astronomers with smaller backyard telescopes could see the dust cloud backdropped by the darker lunar surface.

"We are calling upon astronomical observatories and amateurs worldwide to participate in a coordinated observation effort with SMART-1, including the final orbits until impact," said European Space Agency SMART-1 project scientist Bernard Foing.

Instruments to be operating during SMART-1's final hours include an infrared spectrometer, an X-ray spectrometer, and a tiny camera to take pictures of the Moon as the spacecraft passes near the surface.

The material propelled into sunlight will be closely analyzed to determine details such as its mineral composition and physical properties. Some of the debris could be excavated from underground during SMART-1's crash, so scientists are especially interested in learning about the sub-surface of the Moon.

During SMART-1's final orbits, the spacecraft should be speeding just a few miles above the lunar surface. Accurate predictions of the expected impact time and location are hard to produce because of unknown variations in topography along the probe's trajectory over the Moon. Officials say an unexpected mountain or cliff could cause the craft to crash earlier than anticipated.

By early September, SMART-1 will complete one orbit of the Moon about every five hours. With each orbit's closest approach to the surface, the probe will slowly descend further.

Two low passes before the most likely impact time are also being closely watched in case SMART-1 hits the Moon early. If the spacecraft strikes the Moon at 0037 GMT, observers in South America and the Canary Islands will garner the best view of the event. One orbit earlier - at 1933 GMT on September 2 - astronomers based in Europe and Africa will have the best chance to view the crash.

At first contact, engineers believe SMART-1 will gently glide down at a vertical speed of just under 45 miles per hour, assuming the impact is on a relatively flat surface. However, the craft will be traveling at a horizontal clip of well over 4,000 miles per hour. The low-angle impact could carve a crater up to three feet deep and a couple dozen feet wide.

The testbed carries an efficient ion engine that is fueled by a relatively small amount of xenon fuel and electricity. Strides have also been made in autonomous navigation through ground software that can remotely track the craft's position and velocity through images of stars taken by an on-board camera. Several communications tests through lasers and higher radio frequencies were also carried out.

On the scientific front, SMART-1 has captured and returned up to 1,000 images per week during the past 15 months. Its miniature visible camera is fitted with several color filters, so scientists were also able to take several black-and-white pictures of the same area and artificially create a color image.

The spacecraft's instruments have also been working on studies of lunar composition and the search for ice hidden in the bottoms of polar craters. SMART-1 has also collected evidence on the Moon's evolution and origin. Extensive mapping operations have also been a priority for planning in advance of future lunar missions.

SMART-1 has been circling the Moon since November 2004, almost 14 months after launching aboard an Ariane 5 rocket in September 2003. The probe took a circuitous route to the Moon, completing 332 orbits around Earth while using its electric propulsion system to gently nudge it higher before finally slipping into lunar orbit.

While transitioning to a stable science orbit a few months later, SMART-1 was quickly granted a mission extension in February 2005 that allowed the mission to continue operations through August of this year.

The mission is the first member of the European Space Agency's Small Missions for Advanced Research in Technology program. SMART missions are designed to test new technologies before employing them on more expensive projects.
 
SOURCE: SPACEFLIGHTNOW.COM

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New view of quasar emerges
HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS NEWS RELEASE


In the distant, young universe, quasars shine with a brilliance unmatched by anything in the local cosmos. Although they appear starlike in optical telescopes, quasars are actually the bright centers of galaxies located billions of light-years from Earth.



This artist's conceptual drawing shows the core of a quasar known as
 Q0957+561. Observations indicate that the quasar contains a 4-billion solar-mass object that astronomers have dubbed a
magnetospheric eternally collapsing object, or MECO for short.
Credit: Christine Pulliam (CfA)


The seething core of a quasar currently is pictured as containing a disk of hot gas spiraling into a supermassive black hole. Some of that gas is forcefully ejected outward in two opposing jets at nearly the speed of light. Theorists struggle to understand the physics of the accretion disk and jets, while observers struggle to peer into the quasar's heart. The central "engine" powering the jets is difficult to study telescopically because the region is so compact and Earth observers are so far away.

Astronomer Rudy Schild of the Harvard-Smithsonian Center for Astrophysics (CfA) and his colleagues studied the quasar known as Q0957+561, located about 9 billion light-years from Earth in the direction of the constellation Ursa Major, near the Big Dipper. This quasar holds a central compact object containing as much mass as 3-4 billion Suns. Most would consider that object to be a "black hole," but Schild's research suggests otherwise.

"We don't call this object a black hole because we have found evidence that it contains an internally anchored magnetic field that penetrates right through the surface of the collapsed central object, and that interacts with the quasar environment," commented Schild.

The researchers chose Q0957+561 for its association with a natural cosmic lens. The gravity of a nearby galaxy bends space, forming two images of the distant quasar and magnifying its light. Stars and planets within the nearby galaxy also affect the quasar's light, causing small fluctuations in brightness (in a process called "microlensing") when they drift into the line of sight between Earth and the quasar.

Schild monitored the quasar's brightness for 20 years, and led an international consortium of observers operating 14 telescopes to keep the object under steady around-the-clock watch at critical times.

"With microlensing, we can discern more detail from this so-called 'black hole' two-thirds of the way to the edge of the visible universe than we can from the black hole at the center of the Milky Way," said Schild.

Through careful analysis, the team teased out details about the quasar's core. For example, their calculations pinpointed the location where the jets form.

"How and where do these jets form? Even after 60 years of radio observations, we had no answer. Now the evidence is in, and we know," said Schild.

Schild and his colleagues found that the jets appear to emerge from two regions 1,000 astronomical units in size (about 25 times larger than the Pluto-Sun distance) located 8,000 astronomical units directly above the poles of the central compact object. (An astronomical unit is defined as the average distance from the Earth to the Sun, or 93 million miles.) However, that location would be expected only if the jets were powered by reconnecting magnetic field lines that were anchored to the rotating supermassive compact object within the quasar. By interacting with a surrounding accretion disk, such spinning magnetic field lines spool up, winding tighter and tighter until they explosively unite, reconnect and break, releasing huge amounts of energy that power the jets.

"This quasar appears to be dynamically dominated by a magnetic field internally anchored to its central, rotating supermassive compact object," stated Schild.

Further evidence for the importance of the quasar's internally anchored magnetic field is found in surrounding structures. For example, the inner region closest to the quasar appears to have been swept clean of material. The inner edge of the accretion disk, located about 2,000 astronomical units from the central compact object, is heated to incandescence and glows brightly. Both effects are the physical signatures of a swirling, internal magnetic field being pulled around by the rotation of the central compact object - a phenomenon dubbed the "magnetic propeller effect."

Observations also suggest the presence of a broad cone-shaped outflow from the accretion disk. Where lit by the central quasar, it shines in a ring-like outline known as the Elvis structure after Schild's CfA colleague, Martin Elvis, who theorized its existence. The surprisingly large angular opening of the outflow that is observed is best explained by the influence of an intrinsic magnetic field contained within the central compact object in this quasar.

In light of these observations, Schild and his colleagues, Darryl Leiter (Marwood Astrophysics Research Center) and Stanley Robertson (Southwestern Oklahoma State University), have proposed a controversial theory that the magnetic field is intrinsic to the quasar's central, supermassive compact object, rather than only being part of the accretion disk as thought by most researchers. If confirmed, this theory would lead to a revolutionary new picture of quasar structure.

"Our finding challenges the accepted view of black holes," said Leiter. "We've even proposed a new name for them - Magnetospheric Eternally Collapsing Objects, or MECOs," a variant of the name first coined by Indian astrophysicist Abhas Mitra in 1998. "Astrophysicists of 50 years ago did not have access to the modern understanding of quantum electrodynamics that is behind our new solutions to Einstein's original equations of relativity."

This research suggests that, in addition to its mass and spin, the quasar's central compact object may have physical properties more like a highly redshifted, spinning magnetic dipole than like a black hole. For that reason, most approaching matter does not disappear forever, but instead feels the motor-like rotating magnetic field and gets spun back out. According to this theory, a MECO does not have an event horizon, so any matter that is able to get by the magnetic propeller is gradually slowed down and stopped at the MECO's highly redshifted surface, with just a weak signal connecting the radiation from that matter to a distant observer. That signal is very hard to observe and has not been detected from Q0957+561.

This research was published in the July 2006 issue of the Astronomical Journal.



SOURCE:SPACEFLIGHTNOW.COM




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Planet-forming disks might put the brakes on stars

JET PROPULSION LABORATORY NEWS RELEASE


Astronomers using NASA's Spitzer Space Telescope have found evidence that dusty disks of planet-forming material tug on and slow down the young, whirling stars they surround.
 


This artist's concept demonstrates how a dusty planet-forming disk
can slow down a whirling young star, essentially saving the star
from spinning itself to death. Credit: NASA/JPL-Caltech


Young stars are full of energy, spinning around like tops in half a day or less. They would spin even faster, but something puts on the brakes. While scientists had theorized that planet-forming disks might be at least part of the answer, demonstrating this had been hard to do until now.

"We knew that something must be keeping the stars' speed in check," said Dr. Luisa Rebull of NASA's Spitzer Science Center, Pasadena, Calif. "Disks were the most logical answer, but we had to wait for Spitzer to see the disks."

Rebull, who has been working on the problem for nearly a decade, is lead author of a new paper in the July 20 issue of the Astrophysical Journal. The findings are part of a quest to understand the complex relationship between young stars and their burgeoning planetary systems.

Stars begin life as collapsing balls of gas that spin faster and faster as they shrink, like twirling ice skaters pulling in their arms. As the stars whip around, excess gas and dust flatten into surrounding pancake-like disks. The dust and gas in the disks are believed to eventually clump together to form planets.

Developing stars spin so fast that, left unchecked, they would never fully contract and become stars. Prior to the new study, astronomers had theorized that disks might be slowing the super speedy stars by yanking on their magnetic fields. When a star's fields pass through a disk, they are thought to get bogged down like a spoon in molasses. This locks a star's rotation to the slower-turning disk, so the shrinking star can't spin faster.

To prove this principle, Rebull and her team turned to Spitzer for help. Launched in August of 2003, the infrared observatory is an expert at finding the swirling disks around stars, because dust in the disks is heated by starlight and glows at infrared wavelengths.

The team used Spitzer to observe nearly 500 young stars in the Orion nebula. They divided the stars into slow spinners and fast spinners, and determined that the slow spinners are five times more likely to have disks than the fast ones.

"We can now say that disks play some kind of role in slowing down stars in at least one region, but there could be a host of other factors operating in tandem. And stars might behave differently in different environments," Rebull said.

Other factors that contribute to a star's winding down over longer periods of time include stellar winds and possibly full-grown planets.

If planet-forming disks slow down stars, does that mean stars with planets spin more slowly than stars without planets? Not necessarily, according to Rebull, who said slowly spinning stars might simply take more time than other stars to clear their disks and develop planets. Such late-blooming stars would, in effect, give their disks more time to put on the brakes and slow them down.

Ultimately, the question of how a star's rotation rate is related to its ability to support planets will fall to planet hunters. So far, all known planets in the universe circle stars that turn around lazily. Our sun is considered a slowpoke, currently plodding along at a rate of one revolution every 28 days. And, due to limits in technology, planet hunters have not been able to find any extrasolar planets around zippy stars.

"We'll have to use different tools for detecting planets around rapidly spinning stars, such as next-generation ground and space telescopes," said Dr. Steve Strom, an astronomer at the National Optical Astronomy Observatory, Tucson, Ariz.

Other members of Rebull's team include Drs. John Stauffer of the Spitzer Science Center; S. Thomas Megeath at the University of Toledo, Ohio; and Joseph Hora and Lee Hartmann of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. Hartmann is also affiliated with the University of Michigan, Ann Arbor.



SOURCE: SPACEFLIGHTNOW.COM
 


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New definition would add 3 "planets" to Solar System
ASTRONOMICAL UNION NEWS RELEASE
Posted: August 16, 2006

The world's astronomers, under the auspices of the International Astronomical Union (IAU), have concluded two years of work defining the difference between "planets" and the smaller "solar system bodies" such as comets and asteroids. If the definition is approved by the astronomers gathered 14-25 August 2006 at the IAU General Assembly in Prague, our Solar System will include 12 planets, with more to come: eight classical planets that dominate the system, three planets in a new and growing category of "plutons" - Pluto-like objects - and Ceres. Pluto remains a planet and is the prototype for the new category of "plutons."




If the definition is approved by the astronomers gathered at the IAU
 General Assembly in Prague, our Solar System will consist of 12
planets: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn,
Uranus, Neptune, Pluto, Charon and 2003 UB313. The three new
proposed planets are Ceres, Charon (Pluto's companion) and 2003
UB313. Credit: The International Astronomical Union/Martin Kornmesser




With the advent of powerful new telescopes on the ground and in space, planetary astronomy has gone though an exciting development over the past decade. For thousands of years very little was known about the planets other than they were objects that moved in the sky with respect to the background of fixed stars. In fact the word "planet" comes from the Greek word for "wanderer". But today hosts of newly discovered large objects in the outer regions of our Solar System present a challenge to our historically based definition of a "planet".

At first glance one should think that it is easy to define what a planet is - a large and round body. On second thought difficulties arise, as one could ask "where is the lower limit?" - how large, and how round should an asteroid be before it becomes a planet - as well as "where is the upper limit?" - how large can a planet be before it becomes a brown dwarf or a star?

IAU President Ron Ekers explains the rational behind a planet definition: "Modern science provides much more knowledge than the simple fact that objects orbiting the Sun appear to move with respect to the background of fixed stars. For example, recent new discoveries have been made of objects in the outer regions of our Solar System that have sizes comparable to and larger than Pluto. These discoveries have rightfully called into question whether or not they should be considered as new ‘planets.' "

The International Astronomical Union has been the arbiter of planetary and satellite nomenclature since its inception in 1919. The world's astronomers, under the auspices of the IAU, have had official deliberations on a new definition for the word "planet" for nearly two years. IAU's top, the so-called Executive Committee, led by Ekers, formed a Planet Definition Committee (PDC) comprised by seven persons who were astronomers, writers, and historians with broad international representation. This group of seven convened in Paris in late June and early July 2006. They culminated the two year process by reaching a unanimous consensus for a proposed new definition of the word "planet


The three new planets. Credit: The International Astronomical Union/Martin Kornmesser

Owen Gingerich, the Chair of the Planet Definition Committee says: "In July we had vigorous discussions of both the scientific and the cultural/historical issues, and on the second morning several members admitted that they had not slept well, worrying that we would not be able to reach a consensus. But by the end of a long day, the miracle had happened: we had reached a unanimous agreement."

The part of "IAU Resolution 5 for GA-XXVI" that describes the planet definition, states "A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet." Member of the Planet Definition Committee, Richard Binzel says: "Our goal was to find a scientific basis for a new definition of planet and we chose gravity as the determining factor. Nature decides whether or not an object is a planet."

According to the new draft definition, two conditions must be satisfied for an object to be called a "planet." First, the object must be in orbit around a star, while not being itself a star. Second, the object must be large enough (or more technically correct, massive enough) for its own gravity to pull it into a nearly spherical shape. The shape of objects with mass above 5 x 1020 kg and diameter greater than 800 km would normally be determined by self-gravity, but all borderline cases would have to be established by observation.

If the proposed Resolution is passed, the 12 planets in our Solar System will be Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313. The name 2003 UB313 is provisional, as a "real" name has not yet been assigned to this object. A decision and announcement of a new name are likely not to be made during the IAU General Assembly in Prague, but at a later time. The naming procedures depend on the outcome of the Resolution vote. There will most likely be more planets announced by the IAU in the future. Currently a dozen "candidate planets" are listed on IAU's "watchlist" which keeps changing as new objects are found and the physics of the existing candidates becomes better known.


There will most likely be more planets announced by the IAU in the
future. Currently a dozen "candidate planets" are listed on
IAU's "watchlist" which keeps changing as new objects are found and
the physics of the existing candidates becomes better known. A
number of these planet candidates are shown here. Credit: The
International Astronomical Union/Martin Kornmesser


The IAU draft Resolution also defines a new category of planet for official use: "pluton". Plutons are distinguished from classical planets in that they reside in orbits around the Sun that take longer than 200 years to complete (i.e. they orbit beyond Neptune). Plutons typically have orbits that are highly tilted with respect to the classical planets (technically referred to as a large orbital inclination). Plutons also typically have orbits that are far from being perfectly circular (technically referred to as having a large orbital eccentricity). All of these distinguishing characteristics for plutons are scientifically interesting in that they suggest a different origin from the classical planets.

The draft "Planet Definition" Resolution will be discussed and refined during the General Assembly and then it (plus four other Resolutions) will be presented for voting at the 2nd session of the GA 24 August between 14:00 and 17:30 CEST.

The IAU is the international astronomical organisation that brings together distinguished astronomers from all nations of the world. IAU's mission is to promote and safeguard the science of astronomy in all its aspects through international cooperation. Founded in 1919, the IAU is the world's largest professional body for astronomers. The IAU General Assembly is held every three years and is one of the largest and most diverse meetings in the astronomical community's calendar.

SOURCE: SPACEFLIGHTNOW.COM  Hmmm...sticky toffee sauce is also nice ! :)








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Digging up troves of possible solar systems in Orion

NASA/JPL NEWS RELEASE
Posted: August 14, 2006

Astronomers have long scrutinized the vast and layered clouds of the Orion nebula, an industrious star-making factory visible to the naked eye in the sword of the famous hunter constellation. Yet, Orion is still full of secrets.


This infrared image from Spitzer shows the Orion nebula, our closest
massive star-making factory, 1,450 light-years from Earth. The
nebula is close enough to appear to the naked eye as a fuzzy star in
the sword of the popular hunter constellation. The nebula itself is
located on the lower half of the image, surrounded by a ring of
dust. It formed in a cold cloud of gas and dust and contains about 1,000 young stars. These stars illuminate the cloud, creating the
beautiful nebulosity, or swirls of material, seen here in infrared. Credit: NASA/JPL-Caltech/ T. Megeath (University of Toledo)
Download larger image version here


A new image from NASA's Spitzer Space Telescope probes deep into the clouds of dust that permeate the nebula and its surrounding regions. The striking false-color picture shows pinkish swirls of dust speckled with stars, some of which are orbited by disks of planet-forming dust.

Spitzer, with its powerful infrared vision, was able to unearth nearly 2,300 such planet-forming disks in the Orion cloud complex, a collection of turbulent star-forming clouds that includes the well-known Orion nebula.

The disks - made of gas and dust that whirl around young suns - are too small and distant to be seen by visible-light telescopes; however, the infrared glow of their warm dust is easily spotted by Spitzer's infrared detectors. Each disk has the potential to form planets and its own solar system.

"This is the most complete census of young stars with disks in the Orion cloud complex," said Dr. Thomas Megeath of the University of Toledo, Ohio, who led the research. "Basically, we have a census of potential solar systems, and we want to know how many are born in the cities, how many in small towns, and how many out in the countryside."

A look at Orion's demographics reveals that the potential solar systems populate a variety of environments. Megeath and his colleagues found that about 60 percent of the disk-sporting stars in the Orion cloud complex inhabit its bustling "cities," or clusters, containing hundreds of young stars. About 15 percent reside in small outer communities, and a surprising 25 percent prefer to go it alone, living in isolation.

Prior to the Spitzer observations, scientists thought that up to 90 percent of young stars, both with and without disks, dwelled in cities like those of Orion.

"The Orion image shows that many stars also appear to form in isolation or in groups of just a few stars," said team member Dr. John Stauffer of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "These new data may help us to determine the type of environment in which our sun formed."

Astronomers do not know whether our middle-aged sun grew up in the stellar equivalent of the city or countryside, though most favor a large city scenario. Newborn stars like the ones in Orion tend to drift away from their siblings over time, so it is hard to trace an adult star's origins.

Megeath and his colleagues estimate that about 60 to 70 percent of the stars in the Orion cloud complex have disks. "It is an interesting question why this number isn't 100 percent. Eventually, we may be able to understand why some stars don't have disks," said Megeath.

Spitzer's infrared vision also dug up 200 stellar embryos in the Orion cloud complex, most of which had never been seen before. Stellar embryos are still too young to have developed disks.

The Orion cloud complex is about 1,450 light-years from Earth and spans about 240 light-years of space. Spitzer's wide field of view allowed it to survey most of the complex, an area of the sky equivalent to 28 full moons. The featured image shows a slice of this survey, the equivalent of four full moons-worth of sky, and includes the Orion nebula itself.

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. Caltech manages JPL for NASA. Spitzer's infrared array camera, which made the observations, was built by NASA's Goddard Space Flight Center, Greenbelt, Md. The instrument's principal investigator is Dr. Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics.


SOURCE: SPACEFLIGHTNOW.COM

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Large and small stars in harmonious coexistence
HUBBLE EUROPEAN SPACE AGENCY INFORMATION CENTRE
Posted: August 14, 2006



Credit: NASA, ESA and D. A. Gouliermis (MPIA)
Download larger image version here (careful if you have dial up...it's BIG !!



The latest photo from the Hubble Space Telescope, presented at the 2006 General Assembly of the International Astronomical Union in Prague this week, shows a star forming region in the Large Magellanic Cloud (LMC). This sharp image reveals a large number of low-mass infant stars coexisting with young massive stars.

This is a Hubble Space Telescope image of one of the hundreds of star- forming stellar systems, called stellar associations, located 180,000 light-years away in the Large Magellanic Cloud (LMC). The LMC is the second closest known satellite galaxy of our Milky Way, orbiting it roughly every 1.5 billion years.

Earlier ground-based observations of such systems had only allowed astronomers to study the bright blue giant stars in these systems, and not the low-mass stars.

This new, most detailed view to date of the star-forming association LH 95 was taken with Hubble's Advanced Camera for Surveys and provides a extraordinarily rich sample of newly formed low-mass stars, allowing a more accurate calculation of their ages and masses. An international team of astronomers, led by Dimitrios Gouliermis of the Max-Planck Institute for Astronomy (MPIA) in Heidelberg, is currently studying the Hubble data.

According to Dr. Gouliermis "Hubble's sharp vision has over the years dramatically changed the picture that we had for stellar associations in the Magellanic Clouds". The LMC is a galaxy with relatively small amounts of elements heavier than hydrogen, giving astronomers an insight into star-formation in environments different from our Milky Way.




These images reveal details of the LH 95 region. From
top to bottom and left to right they show a dense part of the
parental molecular cloud, a compact cluster of faint infant stars,
the main part of LH 95, where massive and low-mass stars coexist
close to a dusty lane, and one of the remarkable background
galaxies. Credit: NASA, ESA

Download larger image version here




 
Once massive stars - those with at least 3 times the mass of the Sun - have formed, they generate strong stellar winds and high levels of ultraviolet radiation that ionize the surrounding interstellar gas. The result is a nebula of glowing hydrogen that will expand out into the molecular cloud that originally collapsed to form these stars. The blue haze seen throughout the image around LH 95 is actually part of this bright nebula, known as DEM L 252.

Some dense parts of this star-forming region have not been completely eroded by the stellar winds and can still be seen as dark dusty filaments in the picture. Such dust lanes absorb parts of the blue light from the stars behind them, making them appear redder. Other parts of the molecular cloud have already contracted to turn into glowing groups of infant stars, the fainter of which have a high tendency to cluster.

The new Hubble view of LH 95 shows that there are at least two small compact clusters associated with such groups, one to the right, above the centre of the picture and one to the far left. These stellar nurseries host hundreds of newly discovered infant low- mass stars. Such stars have also been found by Hubble in the main part of LH 95 amongst its massive bright stellar members.

This deep image also reveals a variety of distant galaxies, seen as reddish spirals and elliptical galaxies decorating the background of LH 95.

The Large and Small Magellanic Clouds can be seen by the naked eye in the southern hemisphere.

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.


Source: SPACEFLIGHTNOW.COM

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Surprising observations shake up galactic theories
UNIVERSITY OF COLORADO-BOULDER NEWS RELEASE
Posted: August 14, 2006

A heavy form of hydrogen created just moments after the Big Bang has been found to exist in larger quantities than expected in the Milky Way, a finding that could radically alter theories about star and galaxy formation, says a new international study led by the University of Colorado at Boulder.




This is a false-color image of the star AE Aurigae (bright source of
light slightly off center of image) embedded in a region of space
containing smoke-like filaments of carbon-rich dust grains, a common
phenomenon. Such dust might be hiding deuterium, an isotope of
hydrogen, and stymieing astronomers' efforts to study star and
galaxy formation. The FUSE satellite has surveyed the local
deuterium concentration in the galaxy and found far more than
expected. Because deuterium is a tracer of star and galaxy
evolution, this discovery could radically alter theories about how
stars and galaxy form. Credit: T.A. Rector and B.A. Wolpa, NOAO,
AURA, and NSF
Download larger image versionhere


CU-Boulder astrophysicist Jeffrey Linsky said new data gathered by NASA's Far Ultraviolet Spectroscopic Explorer, or FUSE, satellite, shows why deuterium appears to be distributed unevenly in the Milky Way Galaxy. It apparently has been binding to interstellar dust grains, changing from an easily detectable gaseous form to an unobservable solid form, said Linsky, a fellow of JILA, a joint institute of CU-Boulder and the National Institute of Standards and Technology.

The FUSE deuterium study, six years in the making, solves a 35-year- old mystery concerning the distribution of deuterium in the Milky Way while posing new questions about how stars and galaxies are made, according to the research team. A paper on the subject by a team of international researchers led by Linsky is being published in the Aug. 20 issue of The Astrophysical Journal.

"Since the 1970s, we have been unable to explain why deuterium levels vary all over the place," said Linsky. "The answer we found is as unsettling as it is exciting."

Since deuterium -- a hydrogen isotope containing a proton and a neutron -- is believed burned and lost forever during star formation, scientists think the amount of deuterium present in the universe is "pure" and serves as a tracer for star creation and galaxy building over billions of years, said Linsky. While primordial deuterium in the distant, early universe has been measured at concentrations of about 27 parts per million parts hydrogen atoms, measurements by FUSE and NASA's Copernicus satellite have shown a "patchy" distribution of the element in the Milky Way galaxy, often at far lower levels.

In 2003, Princeton University's Bruce Draine, a co-author on the new study, developed a model showing that deuterium, when compared to hydrogen, might preferentially bind to interstellar dust grains. The observations by FUSE -- which can detect the telltale spectral fingerprints of deuterium in the ultraviolet energy range -- strongly support the theory, according to The Astrophysical Journal paper authors.

"Where there are high concentrations of interstellar dust in the galaxy, we see lower concentrations of deuterium gas with FUSE," said Linsky. "And where there is less interstellar dust, we are measuring higher levels of deuterium gas."

In relatively undisturbed areas of the universe -- like regions around Earth's sun, for example -- deuterium atoms systematically "leave" the gas phase and replace normal hydrogen atoms in dust grains, said Linsky. When a pocket of the universe is disturbed by events like a supernova shock wave or violent activity triggered by nearby hot stars, the dust grains are vaporized, releasing deuterium atoms back into a gas, which has been measured by FUSE, the researchers said.

Scientists assumed from astrophysical theories that at least one- third of the primordial deuterium present in the Milky Way was destroyed over time as it cycled through the stars, said Linsky. But according to the new FUSE findings, the present-day deuterium abundance is less than 15 percent below the primordial values.

"This implies that either significantly less material has been converted to helium and heavier elements in stars or that much more primordial gas has rained down onto the galaxy over its lifetime than had been thought," said Linsky. "In either case, our models of the chemical evolution of the Milky Way will have to be revised significantly to explain this important new result."

Launched in 1999, FUSE is a NASA Explorer mission developed in cooperation with the French and Canadian Space Agencies and by Johns Hopkins University, CU-Boulder and the University of California, Berkeley. CU-Boulder's Center for Astrophysics and Space Astronomy designed and built the mission's $9 million spectrograph, which collects and funnels UV light from the satellite's four telescopes.

The paper was co-authored by scientists from Princeton, Johns Hopkins and Northwestern universities, the Space Telescope Science Institute, CU-Boulder, the University of Wisconsin-Madison, the University of Texas-Austin, NASA-Goddard, the Laboratoire d'Astrophysique in Marseille, France, and the Observatoire de Paris- Meudon in Meudon, France.

Other CU-Boulder co-authors include JILA's Brian Wood, CASA's Michael Shull and CASA doctoral graduate Seth Redfield.

SOURCE: SPACEFLIGHTNOW.COM

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Hubble images some of galaxy's dimmest stars
RICE UNIVERSITY NEWS RELEASE
Posted: August 17, 2006

Using the Hubble Space Telescope, astronomers have imaged some of
 the galaxy's oldest and dimmest stars, offering a rare experimental
 glimpse of two mysterious star types tiny, slow burners less than
one-tenth the size of our sun and once giant stars that still glow
more than 10 billion years after their deaths.


 


Looking like glittering jewels, the stars in this
Hubble Space Telescope image at left are part of the ancient
globular star cluster NGC 6397. The image at lower right shows the
faintest red dwarf star (the red dot within the red circle) spied by
 Hubble. The image at upper right pinpoints one of the dim white
dwarfs (the blue dot within the blue circle) seen by Hubble. Credit:
NASA, ESA, and H. Richer (University of British Columbia)



The research appears in this week's issue of the journal Science.

"This project pushed the limits of what even Hubble can do," said study co-author Jay Anderson, a research scientist at Rice University. "These stars can't be reliably detected in a single image. You have to combine a large number of images to find them."

In total, the research team trained Hubble's cameras on the same patch of sky for more than 75 hours, gathering 378 overlapping images. The target was a region of space containing about 1 percent of the globular cluster NGC 6397 a collection of stars that formed early in our galaxy's history.

"When we look at random stars in the sky they have a variety of ages," Anderson said. "Globular clusters offer unique opportunities for astronomers to study a population of stars that are all the same age. All the stars we see in clusters are ancient, because they were created when the galaxy was forming. They're fossils from the galaxy's earliest days."

There are about 150 globular clusters in our galaxy, and most contain between 100,000 and 1 million stars. While most of the galaxy's stars including our own sun orbit the galactic center in the plane of the galaxy, globular clusters predate the flattening of the Milky Way, so they're scattered in a more spherical distribution.

NGC 6397 is one of the nearest clusters to Earth, located just 8,500 light years away. But even at this relatively close astronomical distance, the light from NGC 6397's faintest stars is easily lost in the glare from its brightest stars.

To survey the dimmest objects, Anderson and colleagues relied on computers. Anderson, whose specialty is writing programs to sift through astronomical data, spent months writing and refining software that could examine each Hubble image, pixel by pixel, and find the faintest stars.

The two types of object imaged represent the heavy end and the light end of the stellar mass spectrum.

A star's destiny is determined by its mass. There's a minimum mass that a star must have in order to burn hydrogen, and objects below that threshold cool rapidly and fade away. From the NGC 6397 survey, Anderson and his colleagues identified the smallest visible stars yet seen in a globular cluster, stars less than one-tenth the mass of Earth's sun. This is very near the predicted theoretical threshold, and Anderson said data from the survey will be helpful for verifying and refining theories about the structure and evolution of low-mass stars.

On the other end of the stellar mass spectrum are stars that are significantly larger than the sun. Stars about eight times the mass of the sun burn quickly and die in spectacular planetary nebulae, explosions that spew much of the star's material into space. Upon their final collapse, these stars become white dwarfs, extremely dense objects that radiate heat for billions of years as they slowly fade into darkness. Anderson said that while the brightest and therefore youngest white dwarfs have been seen in many clusters, the new survey yielded the first images of the faintest and oldest white dwarfs in an ancient cluster. The brightness of the white dwarfs at this end of the scale can help astronomers find out how long the stars have been cooling. From that, they can better determine the age of the cluster, which in turn can be used to narrow estimates of the lower limit of the age of the universe.

SOURCE: spaceflightnow.com

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Mystery of Quintuplet stars in Milky Way solved
ROCHESTER INSTITUTE OF TECHNOLOGY NEWS RELEASE
Posted: August 17, 2006

For the first time, scientists have identified the cluster of Quintuplet stars in the Milky Way's galactic center, next to the super massive black hole, as massive binary stars nearing the end of their life cycle, solving a mystery that had dogged astronomers for more than 15 years.




A Yin and Yang in the Galactic Center. High-resolution infrared
images of the dusty pinwheel nebulae are shown inset overlaid on a
Hubble Space Telescope image of the Quintuplet cluster. Each of the
five bright red stars is now thought to be a pinwheel nebula.
Credit: Peter Tuthill (Sydney U.), Keck Observatory, Donald Figer

(RIT).
 

 
The nature of the stars was not entirely clear until now. In a paper published in the Aug. 18 issue of Science, co-authors Peter Tuthill of the University of Sydney and Donald Figer of Rochester Institute of Technology show that the Quintuplet cluster consists of young massive binary stars that produce large amounts of dust. Their data reveal that five bright red stars are nearing the end of their "short" lives of approximately 5 million years. These quickly evolving stars burn fast and bright, but die younger than fainter stars, which live for billions of years. The study captures the Quintuplet stars just before disintegrating in supernovae explosions.

Using advanced imaging techniques on the world's biggest telescope at the W.M. Keck Observatory in Hawaii, the scientists captured the stars at the highest attainable resolution for the instrument, far exceeding the capability of the Hubble Space Telescope, which imaged the cluster a decade ago. The extra-resolution gives scientists a new glimpse of the dust plumes surrounding the stars and the swirling spirals Tuthill likened to pinwheels when he identified the first one in 1999 elsewhere in the galaxy.

"Only a few pinwheels are known in the galaxy," Figer says. "The point is, we've found five all next to each other in the same cluster. No one has seen anything like this before."

According to Figer, the swirling dust in pinwheel stars is key to the presence of the most evolved massive stars and points to the presence of pairs of stars. The geometry of the plume allows scientists to measure the properties of the binary stars, including the orbital period and distance.

"The only way that pinwheels can form is if they have two stars, swirling around each other. The stars are so close that their winds collide, forming dust in a spiral shape, just like water sprayed from a garden hose of a twirling sprinkler," Figer says. "A single star wouldn't be able to produce the dust and wouldn't have the spiral outflow."

An earlier study by Figer in 1996 claimed the Quintuplet cluster consists of evolved massive stars that produce dust. Figer's research could not be confirmed until now with the use of the Keck telescope.

"If you want to understand star formation, you have to understand if they are forming alone or if they have partners," Figer says. "The answer gives us a clue as to whether stars form alone or with companions."


Source: spaceflightnow.com








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Eternal life of stardust portrayed in Spitzer image
UNIVERSITY OF ARIZONA NEWS RELEASE


This vibrant image from NASA's Spitzer Space Telescope
shows the Large Magellanic Cloud, a satellite galaxy to our own
Milky Way galaxy. Credit: NASA/JPL-Caltech/M. Meixner (STScI) & the
 SAGE Legacy Team

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Astronomers have combined hundreds of thousands of Spitzer Space Telescope images into a map of the whole Large Magellanic Cloud. They see features throughout the galaxy in such sharp detail that they can count newly formed stars, determine how much dust old stars are pumping into the galaxy and, for the first time, to sensitively map the rate at which stars are forming across an entire galaxy.

"We can use this amazing map to really start to understand in detail how a galaxy evolves," said Karl Gordon of the University of Arizona Steward Observatory. Gordon heads the UA group who processed 600,000 images that Spitzer's Multiband Imaging Photometer (MIPS) took of the Large Magellanic Cloud.

The Large Magellanic Cloud, a satellite galaxy of our Milky Way about 160,000 light years away, is an ideal astrophysical laboratory for studying the lifecycle of galaxies.

Using Spitzer's unprecedented sensitivity across a spectrum of infrared wavelengths, "We now can study some details in another galaxy that so far we've been able to study only in our own galaxy," Gordon said.

Spitzer scientists combined some of the MIPS images with others taken by the Infrared Array Camera (IRAC), a Spitzer instrument that takes images at shorter infrared wavelengths than MIPS does. The result is a composite picture of 300,000 images of the Large Magellanic Cloud, a picture that shows everything from hot stars to cold dust between the stars, or the interstellar medium.

"What's exciting and significant is that our images go really deep in the galaxy, deep enough to get a life cycle of the interstellar medium, a life cycle of dust. We see young stars which consume dust as they form in dusty molecular clouds and old stars which are ejecting dust back into the interstellar medium.

"We can now test sophisticated theories about how stars form, how they evolve, what the different populations are, and how important they are in a global galaxy environment," Gordon said. "One of the strengths of this is not just that we've measured a small piece of the galaxy, but we've measured almost the entire galaxy in deep, sharp detail."

The survey of the Large Magellanic Cloud is among 19 key "Legacy" projects undertaken by NASA's Spitzer Space Telescope, which was launched August 2003. The project is headed by Margaret Meixner of the Space Telescope Science Institute in Baltimore. Others from the UA Steward Observatory who are reporting this research in the Astronomical Journal are Charles W. Engelbracht, Bi-Qing For, Karl Misselt, Jason Harris, Douglas Kelly, Pablo Perez-Gonzalez and Dennis Zaritsky.

SOURCE: SPACEFLIGHTNOW.COM





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Incredible cliffs of Dione
CASSINI PHOTO RELEASE




Credit: NASA/JPL/Space Science Institute
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This splendid view showcases Dione's tortured complex of bright cliffs. At lower right is the feature called Cassandra, exhibiting linear rays extending in multiple directions.

The trailing hemisphere of Dione (1,126 kilometers, or 700 miles across) is seen here. North is up.

The image was taken in polarized green light with the Cassini spacecraft narrow-angle camera at a distance of approximately 263,000 kilometers (163,000 miles) from Dione. Image scale is 2 kilometers (1 mile) per pixel.

SOURCE:SPACEFLIGHTNOW.COM

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Space station streaks over Atlantis
SPACEFLIGHT NOW
Posted: September 5, 2006

As space shuttle Atlantis stands bathed in powerful flood lights at launch pad 39B on the evening before blastoff, its destination -- the International Space Station -- soars overhead as photographed in this time-lapse image from the Kennedy Space Center press site.


Credit: Ben Cooper/Spaceflight Now
 

SOURCE: SPACEFLIGHTNOW>COM





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Planet or failed star? Hubble finds strange object
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: September 7, 2006

Astronomers using NASA's Hubble Space Telescope have photographed one of the smallest objects ever seen around a normal star beyond our Sun. Weighing in at 12 times the mass of Jupiter, the object is small enough to be a planet. The conundrum is that it's also large enough to be a brown dwarf, a failed star.



This Hubble image shows the brown dwarf candidate,
called CHXR 73 B, as the bright spot at lower right. It orbits a red
 dwarf star, dubbed CHXR 73, which is a third less massive than the
Sun. Credit: NASA, ESA and K. Luhman (Penn State University)

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The Hubble observation of the diminutive companion to the low-mass red dwarf star CHXR 73 is a dramatic reminder that astronomers do not have a consensus in deciding which objects orbiting other stars are truly planets -- even though they have at last agreed on how they will apply the definition of "planet" to objects inside our solar system.

Kevin Luhman of Penn State University in University Park, Pa., leader of the team that found the object, called CHXR 73 B, is casting his vote for a brown dwarf. "New, more sensitive telescopes are finding smaller and smaller objects of planetary-mass size," said Luhman. "These discoveries have prompted astronomers to ask the question, are planetary-mass companions always planets?"

Some astronomers suggest that an extrasolar object's mass determines whether it is a planet. Luhman and others advocate that an object is only a planet if it formed from the disk of gas and dust that commonly encircles a newborn star. Our solar system planets formed 4.6 billion years ago out of a dust disk around our Sun.

Brown dwarfs, by contrast, form just like stars: from the gravitational collapse of large, diffuse clouds of hydrogen gas. Unlike stars, brown dwarfs do not have quite enough mass to ignite hydrogen fusion reactions in their cores, which power stars such as our Sun.

CHXR 73 B is 19.5 billion miles from its red dwarf sun. That's roughly 200 times farther than Earth is from our Sun. At 2 million years old, the star is very young when compared with our middle-aged 4.6-billion-year-old Sun.

"The object is so far away from its star that it is unlikely to have formed in a circumstellar disk," Luhman explained. Disks around low-mass stars are about 5 to 10 billion miles in diameter. There isn't enough material at that distance from the red dwarf to create a planet. Theoretical models show that giant planets like Jupiter form no more than about 3 billion miles from their stars.



This is an artist's concept of the red dwarf star CHXR
73 (upper left) and its companion CHXR 73 B in the foreground (lower
right) weighing in at 12 Jupiter masses. Credit: NASA, ESA and G.
Bacon (STScI)

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Hubble's Advanced Camera for Surveys discovered the object while conducting a survey of free-floating brown dwarfs. Astronomers have found hundreds of brown dwarfs in our galaxy since the first brown dwarfs were spied about a decade ago. Most of them are floating through space and not orbiting stars.

"It is important to study young star systems to understand how small bodies formed. Young brown dwarfs are brighter than older, cooler brown dwarfs. This allows them to be seen even at lower masses, where older dwarfs would still be undetectable," said team member John Wilson of the University of Virginia in Charlottesville.

One way to further settle the uncertainty would be if a disk of dust could be observed around CHXR 73's companion. Like stars, brown dwarfs have circumstellar disks, too. They would be no more than about 2 billion miles in diameter.

NASA's Spitzer Space Telescope has detected disks around several free-floating brown dwarfs. But CHXR 73 B is too close to its star for Spitzer to detect the disk. So astronomers will have to wait for the launch of the James Webb Space Telescope in 2013 to determine if this companion has a disk. The Webb telescope will combine Hubble's sharpness, which is needed for detecting close companions, and Spitzer's infrared sensitivity, which is necessary for seeing cool, dusty disks.

The team's result will appear in the Sept. 20 issue of the Astrophysical Journal.


SOURCE: SPACEFLIGHTNOW.COM





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Earliest New World Writing Discovered

 A heap of debris taken from a quarry in Veracruz, Mexico has yielded a stone block inscribed with what appears to be the oldest writing ever found in the Americas. Numerous symbols are carved across the block in rows. Experts say the block dates back almost 3,000 years, and was created by people from the Olmec civilization. The Olmec were an early central American people who rose to prominence before the heyday of the Maya.

It is a once-in-a-lifetime discovery, says Stephen Houston, an archeologist at Brown University.

The inscriptions are hieroglyphics -- 62 small drawings in rows, with some of the signs repeated up to four times.

"It's not just a set of symbols that might be placed together the way you might see, let's say, on medieval French or English painting," Houston says. "Rather, they are arranged in a sequence that is meant to reflect a language with grammatical elements and with a word order that makes sense."

There are 28 different glyphs -- as archeologists call the signs for short. Some look like vegetables. One looks like a sharp awl or pick. Some symbols are repeated, such as a symbol that looks like an insect. Houston suspects that one symbol might be some sort of punctuation. Some sequences of symbols are separated from the rest, in what look like poetic couplets.

Not all of these symbols are unfamiliar to archeologists. Mary Pohl at Florida State University is an expert on the Olmec. She's analyzed Olmec symbols on jewelry and a cylindrical seal that dates almost as far back as the inscribed tablet. She says a few of the symbols are clearly written versions of carved stone objects, like an ear of corn, previously found at Olmec archeological sites.

"One sign looks actually like a corn cob with silk coming out the top," Pohl says. Other signs are unique, she says, and never before seen, like one of an insect.

Pohl says these objects -- and thus probably the writing -- had a special value in rituals.

"We see that the writing is very closely connected with ritual and the early religious beliefs, because they are taking the ritual carvings and putting them into glyphs and making writing out of them," Pohl says. "And all of this is occurring in the context of the emergence of early kings and the development of a centralized power and stratified society."

The tablet and inscriptions are described in the journal Science. Its date is based on other artifacts found nearby, and may need further confirmation.

Houston and scientists from Mexico who first identified the text say they have no idea what it actually says. With no previous text to work from, deciphering it will be difficult.

What's needed are more texts for comparison. Archeologists say there are a lot of Olmec sites in Mexico that are still unexplored, and any one could hold the key to reading the oldest known language in the Americas.


Front view of a stone block recently discovered in
Veracruz, Mexico. It's inscribed with 28 different signs, some of
them repeated.  Science © 2006




A recreation of the symbols and their placement on the
Veracruz stone block.  Science © 2006



A previously discovered cylinder seal from San Andres,
Tabasco, Mexico, showing glyphs also created by the Olmec
civilization. The writings are estimated to date from 650 B.C.

 


SOURCE:NPR.ORG



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Meet the Earliest Baby Girl ever Discovered!

Discovery of an Australopithecus afarensis child will help to answer important questions concerning human evolution
   
   
   


3.3 million years ago, a three year old girl died in present day Ethiopia, in an area called Dikika. Though a baby, she provides researchers with a unique account of our past, as would a grandmother. Her completeness, antiquity, and age at death combine make this find unprecedented in the history of paleoanthropology and open many new research avenues to investigate into the infancy of early human ancestors. The extraordinary discovery reported this week in the scientific journal Nature, was found in north-eastern Ethiopia, by a paleoanthropological research team led by Dr. Zeresenay Alemseged of the Max Planck Institute in Leipzig, Germany. The scientific significance of the new find is multi-fold, contributing substantially to our comprehension of the morphology, body plan, behaviour, movement and developmental patterns of our early ancestors. After full cleaning and preparation of the fossil it will be possible to reconstruct, for the first time, much of an entire body of a 3 year-old Australopithecus afarensis child, which will resolve many pending questions regarding early human evolution.



Fig. 1: The skull of the Australopithecus afarensis child.

Image: National Museum of Ethiopia, Addis Ababa



The new find consists of a skeleton of the earliest and most complete juvenile human ancestor ever found that lived 150,000 years before Lucy. She was only three years old when she died and belongs to Australopithecus afarensis (the Lucy species) and was found in an area called Dikika, in Ethiopia, by a paleoanthropological team, the DRP (Dikika Research Project) led by Dr. Zeresenay Alesmeged of the Max Planck Institute. The DRP is an international and multidisciplinary project including several researchers with diverse areas of expertise, and about 40 assistants conducting field research in Ethiopia every year. The first piece of the baby was found on December 10th, 2000, but recovering the partial skeleton required intensive searching and sifting over four successive field seasons




 Some of the postcranial (the skeleton other than the head) elements of the Dikika skeleton.

Image: National Museum of Ethiopia, Addis Ababa



SOURCE: EUREKAALERT.ORG

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You may like the picture I posted in this topic.
http://www.thenakedscientists.com/forum/topic.asp?TOPIC_ID=5360


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Hundreds of young galaxies found in early universe
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: September 24, 2006

Astronomers analyzing two of the deepest views of the cosmos made with NASA's Hubble Space Telescope have uncovered a gold mine of galaxies, more than 500 that existed less than a billion years after the Big Bang. These galaxies thrived when the cosmos was less than 7 percent of its present age of 13.7 billion years. This sample represents the most comprehensive compilation of galaxies in the early universe, researchers said.





The discovery is scientifically invaluable for understanding the origin of galaxies, considering that just a decade ago early galaxy formation was largely uncharted territory. Astronomers had not seen even one galaxy that existed when the universe was a billion years old, so finding 500 in a Hubble survey is a significant leap forward for cosmologists.

The galaxies unveiled by Hubble are smaller than today's giant galaxies and very bluish in color, indicating they are ablaze with star birth. The images appear red because of the galaxies' tremendous distance from Earth. The blue light from their young stars took nearly 13 billion years to arrive at Earth. During the journey, the blue light was shifted to red light due to the expansion of space.

"Finding so many of these dwarf galaxies, but so few bright ones, is evidence for galaxies building up from small pieces -- merging together as predicted by the hierarchical theory of galaxy formation," said astronomer Rychard Bouwens of the University of California, Santa Cruz, who led the Hubble study.

SOURCE: SPACEFLIGHTNOW.COM


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Opportunity rover arrives at dramatic vista
NASA NEWS RELEASE
Posted: September 27, 2006

NASA's Mars Rover Opportunity has arrived at the rim of a crater approximately five times wider than a previous stadium-sized one it studied for half a year.


Credit: NASA/JPL-Caltech
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Initial images from the rover's first overlook after a 21-month journey to "Victoria Crater" show rugged walls with layers of exposed rock and a floor blanketed with dunes. The far wall is approximately one-half mile from the rover.

"This is a geologist's dream come true," said Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for NASA's twin rovers Opportunity and Spirit. "Those layers of rock, if we can get to them, will tell us new stories about the environmental conditions long ago. We especially want to learn whether the wet era that we found recorded in the rocks closer to the landing site extended farther back in time. The way to find that out is to go deeper, and Victoria may let us do that."

Opportunity has been exploring Mars since January 2004, more than 10 times longer than its original prime mission of three months. It has driven more than 5.7 miles. Most of that was to get from "Endurance" crater to Victoria, across a flat plain pocked with smaller craters and strewn with sand ripples. Frequent stops to examine intriguing rocks interrupted the journey, and one large sand ripple kept the rover trapped for more than five weeks

SOURCE : SPACEFLIHTNOW.COM


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