August 25, 2007, 7:24 AM CT

Software Coordinates 19 Mirrors

Researchers and engineers have created and successfully tested a set of algorithms and software programs which are designed to enable the 19 individual mirrors comprising NASA's powerful James Webb Space Telescope to function as one very sensitive telescope.

NASA scientists will present findings on these algorithms and software programs, called the "Wavefront Sensing and Controls" at the Optics and Photonics meeting of the Society for Photo-Optical Instrumentation Engineers (SPIE) meeting. The SPIE meeting will be held at the San Diego Convention Center, 111 West Harbor Drive, San Diego, Calif., August 26-30. The session, called "TRL-6 for JWST Wavefront Sensing and Control" will be on Sunday, August 26 from 11:30 a.m. - 11:50 a.m. PDT, in room 29B, and is Paper 6687-7 of Conference 6687.

After its launch in 2013, when the Webb Telescope settles into its vantage point about one million miles from Earth, and periodically thereafter, the orientations of the telescope's 18 primary mirror segments and the position of the secondary mirror will have to be adjusted to bring light from the universe into focus. Through a process called "Wavefront Sensing and Control," or WFSC, software aboard the observatory will compute the optimum position of each of the 19 mirrors, and then adjust the positions, if necessary......... Posted by: Sean      Read more         Source

August 23, 2007, 10:09 PM CT

Gaping Hole In The Universe

University of Minnesota astronomers have found an enormous hole in the Universe, nearly a billion light-years across, empty of both normal matter such as stars, galaxies and gas, as well as the mysterious, unseen dark matter. While earlier studies have shown holes, or voids, in the large-scale structure of the Universe, this new discovery dwarfs them all.

Not only has no one ever found a void this big, but we never even expected to find one this size, said Lawrence Rudnick of the University of Minnesota astronomy professor. Rudnick, along with grad student Shea Brown and associate professor Liliya Williams, also of the University of Minnesota, reported their findings in a paper accepted for publication in the Astrophysical Journal.

Astronomers have known for years that, on large scales, the Universe has voids largely empty of matter. However, most of these voids are much smaller than the one found by Rudnick and colleagues. In addition, the number of discovered voids decreases as the size increases.

What weve found is not normal, based on either findings based on observation or on computer simulations of the large-scale evolution of the Universe, Williams said.

The astronomers drew their conclusion by studying data from the NRAO VLA Sky Survey (NVSS), a project that imaged the entire sky visible to the Very Large Array (VLA) radio telescope, part of the National Science Foundation's National Radio Astronomy Observatory (NRAO). Their study of the NVSS data showed a remarkable drop in the number of galaxies in a region of sky in the constellation Eridanus, southwest of Orion......... Posted by: Sean      Read more         Source

August 21, 2007, 5:46 PM CT

Catching Some Rays

An international team of scientists has detected low-energy solar neutrinos--subatomic particles produced in the core of the sun--and measured in real-time the rate the particles hit our planet.

The scientists also obtained fresh evidence that neutrinos oscillate (transform from one state to another) before arriving at Earth, adding weight to present theories about the nature of neutrinos and the inner workings of the sun and other stars.

The team of more than 100 researchers, including National Science Foundation (NSF)-supported researchers at Princeton University and Virginia Tech, have operated the so-called Borexino experiment in one of the deepest laboratories in the world, the Gran Sasso Laboratory of the Istituto Nazionale di Fisica Nucleare (INFN, the Italian National Institute of Nuclear Physics), near the town of L'Aquila, Italy.

These are the first results from the Borexino experiment that has been under construction since the late 1990s with the support of INFN as the lead agency, NSF in the United States, and institutions in Gera number of, France and Russia.

"In making these first direct measurements of low-energy neutrinos coming from the sun, Borexino represents a convergence of our present understanding of neutrino properties and the physics of solar energy generation," said Brad Keister, program director for nuclear physics in NSF's mathematical and physical sciences directorate......... Posted by: Sean      Read more         Source

August 16, 2007, 9:29 PM CT

Dark matter mystery deepens

Astronomers have discovered a chaotic scene unlike any witnessed before in a cosmic train wreck between giant galaxy clusters. NASAs Chandra X-ray Observatory and optical telescopes revealed a dark matter core that was mostly devoid of galaxies, which may pose problems for current theories of dark matter behavior.

"These results challenge our understanding of the way clusters merge," said Dr. Andisheh Mahdavi of the University of Victoria, British Columbia. "Or, they possibly make us even reexamine the nature of dark matter itself".

There are three main components to galaxy clusters: individual galaxies composed of billions of stars, hot gas in between the galaxies, and dark matter, a mysterious substance that dominates the cluster mass and can be detected only through its gravitational effects.

Optical telescopes can observe the starlight from the individual galaxies, and can infer the location of dark matter by its subtle light-bending effects on distant galaxies. X-ray telescopes like Chandra detect the multimillion-degree gas.

A popular theory of dark matter predicts that dark matter and galaxies should stay together, even during a violent collision, as observed in the case of the so-called Bullet Cluster. However, when the Chandra data of the galaxy cluster system known as Abell 520 was mapped along with the optical data from the Canada-France-Hawaii Telescope and Subaru Telescope atop Mauna Kea, HI, a puzzling picture emerged. A dark matter core was found, which also contained hot gas but no bright galaxies......... Posted by: Sean      Read more         Source

August 7, 2007, 10:35 PM CT

Where chemistry happens for the very first time

Picture a cool place, teeming with a multitude of hot bodies twirling about in rapidly changing formations of singles and couples, partners and groups, constantly dissolving and reforming.

If you were thinking of the dance floor in a modern nightclub, think again.

It's a description of the shells around dying stars, the place where newly formed elements make compounds and life takes off, said Katharina Lodders, Ph.D., research associate professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis.

Chemistry for the very first time

"The circumstellar environment is where chemistry happens for the very first time," said Lodders. "It's the first place a newly synthesized element can do chemistry. It's a supermarket of things from dust to gas and dust grains to molecules and atoms. The circumstellar shells enable a chemistry that produced grains older than our sun itself. It's generated some popular interest, and this year marks the 20th anniversary of the presolar grain discoveries."

After the discovery of presolar diamonds in a meteorite in 1987 - the first stardust found in a meteorite - scientists at Washington University in St. Louis have been prominent in finding and analyzing pre-solar grains made of silicon carbide, diamonds, corundum, spinel, and silicates. The latest discovery - a silicate grain that formed around a foreign star and became incorporated into a comet in our solar system - was captured and returned by the STARDUST space mission in 2006......... Posted by: Sean      Read more         Source

August 6, 2007, 5:26 PM CT

Monster galaxy pileup sighted

New Haven, Conn. Four galaxies are slamming into each other and kicking up billions of stars in one of the largest cosmic smash-ups ever observed.

The clashing galaxies, spotted by NASA's Spitzer Space Telescope and the WIYN Telescope, will eventually merge into a single, behemoth galaxy up to 10 times as massive as our own Milky Way. This rare sighting provides an unprecedented look at how the most massive galaxies in the universe form.

Most of the galaxy mergers we already knew about are like compact cars crashing together, said Kenneth Rines of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. What we have here is like four sand trucks smashing together, flinging sand everywhere. Rines, who was a Mead postdoctoral fellow at Yale from 2003-6 when much of this work was done, is lead author of a paper accepted for publication in Astrophysical Journal Letters.

Collisions, or mergers, between galaxies are common in the universe. Gravity causes some galaxies that are close together to tangle and ultimately unite over a period of millions of years. Though stars in merging galaxies are tossed around like sand, they have a lot of space between them and survive the ride. Our Milky Way galaxy will team up with the Andromeda galaxy in five billion years......... Posted by: Sean      Read more         Source

August 3, 2007, 10:22 PM CT

Star Caught Smoking

Using ESO's Very Large Telescope Interferometer, astronomers from France and Brazil have detected a huge cloud of dust around a star. This observation is further evidence for the theory that such stellar puffs are the cause of the repeated extreme dimming of the star.

R Coronae Borealis stars are supergiants exhibiting erratic variability. Named after the first star that showed such behaviour [1], they are more than 50 times larger than our Sun. R Coronae Borealis stars can see their apparent brightness unpredictably decline to a thousandth of their nominal value within a few weeks, with the return to normal light levels being much slower. It has been accepted for decades that such fading could be due to obscuration of the stellar surface by newly formed dusty clouds.

This 'Dust Puff Theory' suggests that mass is lost from the R Coronae Borealis (or R CrB for short) star and then moves away until the temperature is low enough for carbon dust to form. If the newly formed dust cloud is located along our line-of-sight, it eclipses the star. As the dust is blown away by the star's strong light, the 'curtain' vanishes and the star reappears.

RY Sagittarii is the brightest member in the southern hemisphere of this family of weird stars. Located about 6,000 light-years away towards the constellation of Sagittarius (The Archer), its peculiar nature was discovered in 1895 by famous Dutch astronomer Jacobus Cornelius Kapteyn......... Posted by: Sean      Read more         Source

July 30, 2007, 8:04 PM CT

Japanese and NASA Satellites Unveil New Type of Active Galaxy

An international team of astronomers using NASA's Swift satellite and the Japanese/U.S. Suzaku X-ray observatory has discovered a new class of active galactic nuclei (AGN).

By now, you'd believe that astronomers would have found all the different classes of AGN - extraordinarily energetic cores of galaxies powered by accreting supermassive black holes. AGN such as quasars, blazars, and Seyfert galaxies are among the most luminous objects in our Universe, often pouring out the energy of billions of stars from a region no larger than our solar system.

But by using Swift and Suzaku, the team has discovered that a relatively common class of AGN has escaped detection.....until now. These objects are so heavily shrouded in gas and dust that virtually no light gets out.

"This is an important discovery because it will help us better understand why some supermassive black holes shine and others don't," says astronomer and team member Jack Tueller of NASA's Goddard Space Flight Center in Greenbelt, Md.

Evidence for this new type of AGN began surfacing over the past two years. Using Swift's Burst Alert Telescope (BAT), a team led by Tueller has found several hundred relatively nearby AGNs that were previously missed because their visible and ultraviolet light was smothered by gas and dust. The BAT was able to detect high-energy X-rays from these heavily blanketed AGNs because, unlike visible light, high-energy X-rays can punch through thick gas and dust......... Posted by: Sean      Read more         Source

Tue, 24 Jul 2007 22:13:58 GMT

First Step Towards Universal Colonization?

After leaving their mark all over the world, it is now time for the human beings to find a place elsewhere to accommodate gradually growing community and cater their needs. This time NASA plans to colonize Mars, by means of plantation on the planet and make the place habitable for humans.

NASA scientists are examining a high altitude pine forest in a Mexican volcano Pico de Orizaba in order to find the practicalities of colonizing Mars. Mars has an average temperature of -55 degree Celsius, far too cold for the plant habitation. This temperature can be increased by introducing global warming gases, like nitrous oxide and methane to make the planet warmer. The entire process can be initiated not before 50 years and NASA scientists are quite serious about this project, recent news confirmed.

This was inevitable. The increasing population and worsening of mineral storage all over the world have caused the scientists to think beyond the territory of this planet. Thousands of years of continuous abuse have seen the natural resources drying up in a strangely alarming manner.

The excessive use of greenhouse gases or popularly known as global warming gases has done enough damage to our own planet. Now it is time to use these very gases and more specifically their warming nature to create an environment on Mars that can suit plantation, and finally human population. This is ironic, and needs to be dealt very carefully.

It is all right that we are moving to Mars, but the fundamental question still remains. How long will this colonization support our growing needs and cater to our destructive lifestyles? We need to choose from the options whether we need to go finding colony after colony in the universe, or we should change our own lifestyle to make our planet a better place. The question is daunting and unfortunately, the zeal to find answers to it is missing.

Source Posted by: Swagata      Read more     Source

Tue, 24 Jul 2007 11:29:19 GMT

Astronaut tosses junk from space station

Via Associated Press - Quoted - A spacewalking astronaut did some massive housecleaning at the international space station Monday, tossing out a camera mounting and an ammonia tank weighing more than half a ton. The outdated equipment was no longer needed and joined more than 9,000 pieces of orbital debris already being tracked from Earth. Posted by: Zinzi      Read more     Source