Phoenix mission ready to land on Mars

NASA's Phoenix Mars Lander is preparing to begin a three-month mission to taste and sniff fistfuls of Martian soil and buried ice. The lander is scheduled to touch down on the Red Planet May 25. Phoenix will enter the top of the martian atmosphere at almost 13,000 mph. In 7 minutes, the spacecraft must complete a challenging sequence of events to slow to about 5 mph before its three legs reach the ground. Confirmation of the landing could come as early as 7:53 P.M. EDT. "This is not a trip to grandma's house. Putting a spacecraft safely on Mars is hard and risky," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at NASA headquarters in Washington. "Internationally, fewer than half the attempts have succeeded." Rocks large enough to spoil the landing or prevent opening of the solar panels present the biggest known risk. Images from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, detailed enough to show individual rocks smaller than the lander, have helped lessen that risk. One research goal is to assess whether conditions at the site ever have been favorable for microbial life. The composition and texture of soil above the ice could give clues to whether the ice ever melts in response to long-term climate cycles. Another important question is whether the scooped-up samples contain carbon-based chemicals that are potential building blocks and food for life. Phoenix uses hardware from a spacecraft built for a 2001 launch that was canceled due to the loss of a similar Mars spacecraft during a 1999 landing attempt. Researchers who proposed the Phoenix mission in 2002 saw the unused spacecraft as a resource for pursuing a new science opportunity. Earlier in 2002, NASA's Mars Odyssey orbiter discovered that plentiful water ice lies just beneath the surface throughout much of high-latitude Mars. NASA chose the Phoenix proposal over 24 others to become the first endeavor in the Mars Scout program of competitively selected missions. "Phoenix will land farther north on Mars than any previous mission," said Phoenix Project Manager Barry Goldstein of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. The solar-powered robotic lander will manipulate a 7.7-foot arm to scoop up samples of underground ice and soil lying above the ice. Onboard laboratory instruments will analyze the samples. Cameras and a Canadian weather station will supply other information about the site's environment. "The Phoenix mission not only studies the northern permafrost region, but takes the next step in Mars exploration by determining whether this region, which may encompass as much as 25 percent of the martian surface, is habitable," said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson.

Venus Express finds hydroxyl on Venus

Hydroxyl, an important but difficult-to-detect molecule, is made up of a hydrogen and oxygen atom each. It has now been found in the upper reaches of the Venusian atmosphere about 100 kilometers above the surface by Venus Express' Visible and Infrared Thermal Imaging Spectrometer (VIRTIS). The elusive molecule was detected by turning the spacecraft away from the planet and looking along the faintly visible layer of atmosphere surrounding the planet's disc. The instrument detected the hydroxyl molecules by measuring the amount of infrared light that they give off. The band of atmosphere in which the glowing hydroxyl molecules are located is very narrow; it is only about 10 kilometers wide. By looking at the limb of the planet, Venus Express looked along this faint atmospheric layer, increasing the signal strength by about 50. Hydroxyl is thought to be important for any planet's atmosphere because it is highly reactive. On Earth it has a key role in purging pollutants from the atmosphere and is thought to help stabilize the carbon dioxide in the martian atmosphere, preventing it from converting to carbon monoxide. On Mars it is also thought to play a vital role in sterilizing the soil, making the top layers hostile to microbial life. The reactive molecule has been seen around comets, but the method of production there is thought to be completely different from the way it forms in planetary atmospheres. "Because the Venusian atmosphere had not been studied extensively before Venus Express arrived on the scene, we have not been able to confirm much of what our models tell us by observing what is actually happening. This detection will help us refine our models and learn much more," says one of the principal investigators of the VIRTIS experiment, Giuseppe Piccioni, from the Istituto di Astrofisica Spaziale e Fisica Cosmica in Rome, Italy. On Earth, the glow of hydroxyl in the atmosphere has been shown to be closely linked to the abundance of ozone. From this study, the same is thought to be true at Venus. Now, scientists can set about estimating the amount of ozone in the planet's atmosphere. Venus Express has shown that the amount of hydroxyl at Venus is highly variable. It can change by 50 percent from one orbit to the next and this may be caused by differing amounts of ozone in the atmosphere. "Ozone is an important molecule for any atmosphere, because it is a strong absorber of ultraviolet radiation from the Sun," says Piccioni. The amount of the radiation absorbed is a key parameter driving the heating and dynamics of a planet's atmosphere. On Earth, it heats the stratosphere (the third layer of Earth's atmosphere) making it stable and protecting the biosphere from harmful ultraviolet rays. Computer models will now be able to tell how this jump and drop in ozone levels over short intervals affects the restless atmosphere of that world. "Venus Express has already shown us that Venus is much more Earth-like than once thought. The detection of hydroxyl brings it a step closer," says Piccioni. He and his colleagues are only reporting the initial detection from a few orbits in their latest paper. They are working on the analysis of data from about 50 other orbits and more observations will follow.

Two New Ways to Explore the Virtual Universe, in Vivid 3-D

The skies may be the next frontier in travel, yet not even the wealthiest space tourist can zoom out to, say, the Crab Nebula, the Trapezium Cluster or Eta Carinae, a star 100 times more massive than the Sun and 7,500 light-years away. But those galactic destinations and thousands of others can now be toured and explored at the controls of a computer mouse, with the constellations, stars and space dust displayed in vivid detail and animated imagery across the screen. The project, the WorldWide Telescope, is the culmination of years of work by researchers at Microsoft, and the Web site and free downloadable software are available starting on Tuesday, at www.WorldWideTelescope.org. There are many online astronomy sites, but astronomers say the Microsoft entry sets a new standard in three-dimensional representation of vast amounts data plucked from space telescopes, the ease of navigation, the visual experience and features like guided tours narrated by experts. “Exploring the virtual universe is incredibly smooth and seamless like a top-of-the-line computer game, but also the science is correct,” said Alexander Szalay, a professor of astronomy and physics at Johns Hopkins. “No sacrifices have been made. It just feels as if you are in it.” The WorldWide Telescope project spans astronomy, education and computing. Educators hope its rich images, animation and design for self-navigation will help entice computer-gaming young people into astronomy and science in general. The space service, astronomers say, could also become valuable in scientific discovery, especially with a professional version being developed with the Harvard-Smithsonian Center for Astrophysics. Like many fields of science, astronomy has become digitized and data rich in recent years, making it an ideal proving ground for advanced computing techniques in data mining, visualization and searching. So it is scarcely surprising that the other major company with an ambitious astronomy service online is Google. The Internet search giant first layered astronomical data and images onto Google Earth last August. The switch to astronomy in Google Sky amounts to looking out into space instead of down on Earth. Two months ago, Google introduced a Web-based version of Google Sky, layering space images on its searchable map service. Microsoft and Google are spirited competitors and antagonists in the rough-and-tumble commercial markets of Internet search and software. Yet in online astronomy, both sides proclaim mutual respect and say their sole rivalry is in scientific discovery and public education. They say they have no plans to sell advertising on the astronomy sites. Scientists and educators applaud the interest and investment by the two. “It’s really encouraging that both Microsoft and Google are there, pushing these powerful tools for science education forward,” said Daniel Atkins, director of the National Science Foundation’s Office of Cyberinfrastructure, which focuses on using new technology in learning and research. There may be no space war between Microsoft and Google, but their offerings reflect their different cultures. The WorldWide Telescope results from careful planning and lengthy development in a research division. It has the richer graphics and it created special software to present the images of spherical space objects with less polar distortion. WorldWide Telescope requires downloading a hefty piece of software, and it runs only on Microsoft Windows. Google Sky started as a Google “20 percent” project, in which engineers can spend time on anything they choose. Google Earth, where Google Sky began, requires a software download, but its Web-based version, which came out in March, does not. The Google culture encourages engineers to put new things onto the Internet quickly and keep improving them, a philosophy geared to constant evolution instead of finished products. Despite differences, the companies share motivations. Lior Ron, Google Sky product manager, said the astronomy focus “says a lot about the interests of the people in both companies.” At Google, Mr. Ron, 31, is one of a group of astronomy enthusiasts. He built his own telescope as a teenager and went to astronomy camps in his native Israel. He said he almost joined private space industry last year instead of Google. A personal fascination in astronomy has also energized work at Microsoft. Jonathan Fay, 42, the lead software engineer on the project, has built an observatory, with a dome eight feet in diameter, in his backyard in suburban Seattle. The inspiration for the WorldWide Telescope, and much of the early work, came from Jim Gray, a renowned computer scientist who disappeared last year while sailing alone off northern California. Mr. Gray had long been intrigued by the computing challenges of presenting map and satellite images online. His project to show aerial map images of the world, TerraServer, went up in June 1998, a few months before Google was founded. Mr. Gray then worked for years with astronomers on the concept he presented in Science in September 2001, “The World-wide Telescope.” Mr. Szalay was co-author. Mr. Gray’s vision was largely about making the flood of astronomical data accessible and usable for scientists. The project began to take on its current look and design in fall 2006, when Curtis Wong started working on it full time. Mr. Wong, another amateur astronomer, heads a new media research group at Microsoft, which he joined in 1998. He is the creator of award-winning multimedia CD-ROMs on subjects like the Barnes art collection, Leonardo da Vinci and the making of the atomic bomb. When he came to the astronomy project, Mr. Wong recalled telling Mr. Gray, “This is great, but let’s bring all this data and make it available, accessible and engaging to the public.” A conversation with Mr. Wong, 54, is different from most around the Microsoft campus in Redmond, Wash., which is mainly populated by engineers, marketers and business managers. Mr. Wong speaks of the WorldWide Telescope’s allowing citizen explorers to make and post virtual tours. One tour on the site is by a 6-year-old boy from Toronto. “What we’re starting with is just a foundation,” Mr. Wong said. “When it really gets interesting is when more and more stories populate the WorldWide Telescope.” Young people today are used to sharing stories, on MySpace, Facebook, YouTube and elsewhere. Educators hope that the WorldWide Telescope can entice them to take an interest in astronomy. “Science has a bad rap because it is seen as a dry accumulation of facts,” said Roy R. Gould, a science education expert at the Harvard-Smithsonian Center for Astrophysics. “But this is a visually beautiful environment where you can explore, create and share.”

Supernova Remnant Is Young and Quick

About a century ago, the light from the explosion of a star within our galaxy swept past Earth. No one noticed. Such explosions, called supernovas, can shine brightly in the night sky. But this dying star was close to the center of the galaxy, where thick dust and gas blocked most of the light, and astronomers of the era saw nothing. Now radio telescopes on Earth and the Chandra X-ray Observatory in orbit have taken pictures of the stellar debris, revealing it to be the youngest supernova remnant known in the Milky Way galaxy. The observations, reported in a telephone news conference Wednesday, show that it is still expanding outward at an unexpectedly quick pace of perhaps 30 million miles an hour, or about 5 percent of the speed of light. The rapid expansion means the interstellar gas around the star was thin and did not slow the remnant as much as usual. In addition to that quick expansion, the remnant is growing brighter at radio frequencies: being so young, it is still getting warmer. “It’s doing things we have never seen before,” said Stephen P. Reynolds, a professor of physics at North Carolina State University, who led the Chandra study. While the dust and gas at the galactic core block visible light, other frequencies of light can make it through. David A. Green of the University of Cambridge in England originally identified the supernova remnant in 1985 using the Very Large Array, a Y-shaped configuration of 27 radio telescopes in New Mexico. At the time, he estimated the age at 400 to 1,000 years. Last year Dr. Reynolds pointed Chandra at the same remnant, known as G1.9+0.3. The new X-ray image indicated that G1.9+0.3 had become considerably larger since Dr. Green first looked at it. Dr. Green then took another radio image of the remnant with the Very Large Array and found that the remnant was now about 16 percent wider than in 1985. “We can extrapolate backwards for the age of the object,” Dr. Green said. The star was about 26,000 light-years away. So the actual explosion occurred about 26,000 years ago, and the light from the blast traveled that long to arrive at Earth no more than 150 years ago. The findings will appear in two scientific articles, one in The Astrophysical Journal and one in Monthly Notices of the Royal Astronomical Society. The G1.9+0.3 remnant is still mostly debris from the exploded star. In older remnants, the glow comes from interstellar gases heated by the shock waves rather than pieces of the dead star. “You are actually getting to see the rock that made the splash, not the wave that’s going out into the pond,” said Robert P. Kirshner, a professor of astronomy at Harvard who was not connected with the research. “This is a stellar death, and the corpse is still warm.” The discovery helps fill in the deficit of supernovas for the Milky Way, where the rate of explosions appears much lower than in similar spiral galaxies. “This lack is a significant puzzle,” Dr. Reynolds said. Either astronomers have not been able to identify the remnants, or the Milky Way is somehow different. “Either way,” he said, “is very interesting.”

Chasing the green flash

Solar phenomena are revealed at Paranal.

Provided by European Southern Observatory

The green flash is a rare phenomenon seen at sunrise or sunset, but only
when conditions are just right. Justin Branam [View Larger Image]

May 6, 2008
Cerro Paranal, Chile, home of the European Southern Observatory's (ESO) Very Large Telescope (VLT), is one of the best sites for observation on Earth.

The Earth's atmosphere is a gigantic prism that disperses sunlight. In the most ideal atmospheric conditions, such as those found regularly above Cerro Paranal, this leads to the appearance of green and blue flashes at sunset. The phenomenon is so popular that it is tradition for the Paranal staff to gather daily on the telescope platform to observe the sunset before starting their long night of observations.

The green and blue flashes are fleeting events that require an unobstructed view of the setting Sun, and a very stable atmosphere. These conditions are very often met at Paranal, a mountain in Chile's Atacama Desert, where the sky is cloudless more than 300 days a year.

ESO staff member Stephane Guisard has been chasing green flashes for many years and has captured them on many occasions. "The most challenging is to capture the green flash while still seeing the rest of the Sun with all its colors," he says.

His colleague Guillaume Blanchard was even luckier. On Christmas Eve, while following the tradition of looking at the sunset, he immortalized a blue flash using his hobby telescope.

ESO astronomer Yuri Beletsky also likes to take photographs from Paranal, but prefers night views. This allows him to make use of the unique conditions above the site to make stunning images. On some of these, he has captured other extremely interesting effects related to the Sun: the so-called zodiacal light and the Gegenschein.

Both the zodiacal light and the Gegenschein (German for "counter shine") are due to reflected sunlight by interplanetary dust. These are so faint that they are only visible in places free from light pollution.

Most of the interplanetary dust in the solar system lies in the ecliptic, the plane close to which the planets are moving around the Sun. The zodiacal light and Gegenschein are seen in the region centered around the ecliptic. While the zodiacal light is seen in the vicinity of the Sun, the Gegenschein is seen in the direction opposite the Sun.

Each of the small dust particles, left over from comets and asteroids, acts as a small Moon reflecting the light coming from our host star. "If you could see the individual dust particles then you would see the ones in the middle of the Gegenschein looking like very tiny full moons, while the ones hidden in the faint part of the dust band would look like tiny crescent moons," explains ESO astronomer Colin Snodgrass. "But even the VLT cannot see such tiny individual dust particles out in space. Instead, we see the combined effect, in photos like these, of millions of tiny dust particles reflecting light back to us from the Sun."


Posted by Mikey Pannier
More at: http://www.astronomy.com/asy/default.aspx?c=a&id=6922

Big Stars Need the Help From the Little Guys

We know that there are massive stars out there that can be 10 to 150 times larger than the mass of the sun. These massive stars are rare but produce most the heavy elements in the galaxy when they explode in supernovas. Astrophysicists have been looking at the condition inside cold clouds of molecular hydrogen that favor the formation of massive stars over low-mass stars like the sun. They believe that the early formation of a low mass star in a cloud paves the way for the formation for larger stellar big stars rather than the cloud breaking down into smaller clouds that would produce a bunch of low mass stars. It is when the cloud is cold that it tends to break up into smaller stars but as it gets warmer it can form larger and larger objects. When a star forms in a hydrogen cloud it has a zone of influence around it that it heats up. If it is a low density cloud the influence is small and its effect is unimportant and causes the system to break up. As the density of the cloud increases that influence of the low mass stars warms up the gas and eventually a few low mass stars have heated up the entire cloud causing it to collapse into a massive star. The density of the cloud must be roughly around a million hydrogen molecules per cubic centimeter which is roughly about 10 trillions time greater than earth's atmosphere. scientist also believe that it is possible for low mass stars to form in the outer regions of these clouds where densities are a little less. But this is hard to observe seeings that from earth we can only see the big, bright stars.

http://www.spacedaily.com/reports/Small_Helper_Stars_Needed_For_Massive_Star_Formation_999.html

Oxygen Factory In a Nearby Galaxy

Roughly 160,000 light years away in the Large Megellanic Cloud is the debris of a massive star explosion that was captured by the Chandra X-ray Observatory. This picture is of the brightest of the supernova remnants in the Magellanic clouds, N132D, and is a rare class of oxygen-rich remnants. These type of remnants are thought to be were the oxygen that we breath today has come from. This x-ray image shows low energy x-rays, which appear red, intermediate energy x-rays that appear green and high energy x-rays that appear blue. The majority of the oxygen appears in the green regions of the cloud which are near the center. What is interesting to this cloud is that unlike other oxygen rich debris clouds N132D has an expanding ellipse shaped shell of oxygen. Theoretical work believes that this might be the result of a 'nickel bubble' which occurs shortly after the supernova explosion and is caused by radioactive energy input from nickel that was generated be the explosion. The goal of looking at this star is to further understand the mass of the star that exploded and to learn how these massive stars explode heavy elements like oxygen into space.

Also There May Be Water Under Titan's Crust

Also on Cassini's most recent trip to Titan presents evidence that there may be water and ammonia under the crust. Even though Titan's surface is made of completely different things such as rivers and lakes of methane and organic hydrocarbon dunes it still has the most Earth like surface in the solar system. Cassini has made 19 separate passes over titan between October 2005 and May 2007. Her radar can see through Titan's dense, methane rich atmospheric haze allowing scientist to see features and noting locations on the surface. In using the data from earlier passes scientist searched for the same lakes, canyons, and mountains and found that they were offset by 30 km. Scientist believe that about 100 km beneath the ice and organic-rich surface is and internal ocean of liquid water mixed with ammonia. Titan is the only other planet in the solar system that posses a dense atmosphere, roughly 1.5 times denser than Earth's and is the largest of Saturn's moons and bigger than Mercury. Further passes will help scientist understand the tectonics of Titan as well as these discoveries are very appealing to astrobiologists.

Sand Dunes on Titan

Unlike Earth where sand is the result of weathering and break down of rocks and a lot of other junk. On Titan their sand may be the result of hydrocarbons falling out of the atmosphere and collecting onto sand grain size particles. Recently the orbiter Cassini did another fly by of titan revealing more about the fundamental processes that shape its surface. Information sent back from Cassini shows that the particles are the same complex organic chemicals that make up Titan's atmosphere and that they may contain even less water ice than the rest of Titan. When these particle fall to the ground they are believed to go through a process called sintering which is a slight melting the then welds the particles together allowing them to grow into the perfect size to be blown in the wind and form dunes. This replaces the old idea that most the surface material is water ice with rivers of methane flowing through it, instead it looks like the surface is made mainly of hydrocarbons still with river channels of methane.

http://www.saturndaily.com/reports/Titan_Smoggy_Sand_Grains_999.html

Light Echoes and Supernovas

Sorry the link didn't work

http://www.space.com/php/video/player.php?video_id=080417-light_echo

this Is a Video that has some cool shots about light echoes and how they are used to help understand supernovas

http://www.space.com/php/video/player.php?video_id=080417-light_echo

More of the Matter

Astronomers have just recently discovered new material that will further help explain how the universe works. What they have found is material that is extremely hot, dense and invisible to us, but is not what is known as dark matter. In trying to balance the amount of matter in the universe astronomers can only account for 10 percent of it, the other 90 percent is still hidden to us. The matter that is in the universe that is visible to us that we know makes of the stars, galaxies, planets and everything on them is known and Baryonic matter and only account for 4 percent of the matter in the universe. Astronomers believe that the rest of universe is made up of dark matter which is roughly 21 percent, which has still not been discovered but plays a very important role in the formation of the galaxies after the Big Band. There is also an even more mysterious dark matter that accounts for 75 percent of the universe which caused the accelerated expansion of the universe. Before this discovery Baryonic matter in the universe was accounted for by known gas, stars and galaxies. The missing Baryonic matter as well as dark matter is believed to be a kind of giant spider web that connects galaxy clusters, which sit on threads on knots in the web. This is though to be a extremely hot, ultra thin gas haze of very low density that sits between larger structures and only emits light in the far ultraviolet and x-ray because of its temperature. Astronomers could only see the very dense knots of the web before, but are now seeing the thin connecting wires. This Baryonic has is roughly 150 times hotter than the suns surface and was indirectly detected through the Milky Way and connects about a dozen other galaxies within the local group. This is the stiff that is though to not have fallen in to the galaxies when they first formed, but Finding and analyzing these filaments could help astronomers better understand what happened after the Big Bang and what forces are dominating the universe today.

When Galaxies Collide

Here we see Apr 148, which is two galaxies that have collided with one another creating a ring shape with a long tailed companion. This collided galaxy is in Ursa Major and is roughly 500 million light years away. When they collided it created a shock wave effect that first drew matter into the center and then caused it to expand outward in a ring.
When galaxies collide they create what astronomers call a perfect cosmic storm that can have enough energy output that is second only to the big bang and resembles that of a cosmic hurricane. Recently using space based x-rays astronomers have been able to see the products of galaxy collisions that before were only done in computer simulations. These observations have lead to the idea that the universe formed in a "bottom up" hierarchical structure where stars and galaxies collected and combined together to form larger galaxies and galaxy clusters. The Milky Way is actually believed to be part of a galactic club called the local group which could collide with the Virgo Cluster in a few billion years unless it is prevented due to the expansion of the universe.

Microsoft Does it Again!

Microsoft's WorldWide Telescope delivers the universe

The free program offers seamless exploration of the night sky using real data from multiple observatories.

Francis Reddy

WorldWide Telescope immerses you in astronomical imagery. WWT [View Larger Image] Microsoft took the wraps off its much-anticipated WorldWide Telescope program today. This rich web application merges imagery from the world's best ground- and space-based observatories into a detailed desktop cosmos. The platform also gives scientists and educators a tool for teaching astronomy and the process of scientific discovery. With WorldWide Telescope, users pan left, right, up, down, back, and forward seamlessly — down to the full resolution of the available data. Users can view the stars and planets at any time and date from any point on Earth, explore the sky in dozens of different wavelengths, zoom into images by the Hubble and Spitzer space telescopes, or see Mars from the Opportunity rover's point of view.

Game meets universe "Users can see the X-ray view of the sky, zoom into bright radiation clouds and then cross fade into the visible light view and discover the cloud remnants of a supernova explosion from a thousand years ago," says Roy Gould, a researcher at the Harvard Center for Astrophysics in Cambridge, Massachusetts. "I believe this new creation from Microsoft will have a profound impact on the way we view the universe." WorldWide Telescope "unleashes the power of a game engine on astronomy," says Johns Hopkins University astronomer Alex Szalay. Users can control their own experience or download guided tours highlighting specific astronomical objects. Tours can include narration, music, text, and graphics that create compelling, interactive learning experiences. Users can create and share their own tours as part of the program's communities feature. "With WorldWide Telescope," says David J. Eicher, editor of Astronomy, "cloudy nights, light pollution, and freezing temperatures fall away to an anytime view of the universe in the best personal planetarium ever made." The application is a blend of software and web services created with what Microsoft calls its high-performance Visual Experience Engine, which allows rapid navigation through rich image environments. WorldWide Telescope stitches together terabytes of high-resolution sky photos.

Astronomical roots The project began when Szalay and Jim Gray at Microsoft Research began exploring how to make the terabytes of data captured as part of the Sloan Digital Sky Survey available over the web. One aspect of this work was recognition that astronomers needed a uniform system to easily access all of the world's astronomical data. WorldWide Telescope draws on this system, called the National Virtual Observatory, for the data it displays. Microsoft Research formed close ties with members of the academic, education, and scientific communities to make the project a reality. The WorldWide Telescope team invited Astronomy magazine to host one of the project's first online communities. "Astronomy magazine has a rich tradition of making astronomy easy to understand," says Curtis Wong, manager of Microsoft's Next Media Research Group.

Get it
The software is available free from WorldWideTelescope.org. The estimated download time is 1 hour for dial-up connections, 10 minutes for DSL. The program is graphically intensive and runs only on the Windows operating system. Review the program's requirements to ensure the best experience.


Posted By Mikey Pannier
more at: http://www.astronomy.com/asy/default.aspx?c=a&id=6935

Iron 'Snow'

New scientific evidence suggests that deep inside the planet Mercury, iron "snow" forms and falls toward the center of the planet, much like snowflakes form in Earth's atmosphere and fall to the ground.
The movement of this iron snow could be responsible for Mercury's mysterious magnetic field, say researchers from the University of Illinois and Case Western Reserve University.
Mercury is the innermost planet in our solar system and, other than Earth, the only terrestrial planet that possesses a global magnetic field. Discovered in the 1970s by NASA's Mariner 10 spacecraft, Mercury's magnetic field is about 100 times weaker than Earth's. Most models cannot account for such a weak magnetic field.
Made mostly of iron, Mercury's core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet's magnetic field.
"Recent Earth-based radar measurements of Mercury's rotation revealed a slight rocking motion that implied the planet's core is at least partially molten," said Illinois graduate student Bin Chen, the paper's lead author. "But, in the absence of seismological data from the planet, we know very little about its core."

Full article: http://www.sciencedaily.com/releases/2008/05/080507110712.htm

Antennae Galaxies!!!

Antennae Galaxies move closer
Merging system's interaction sets standard for galaxy evolution.
Provided by European Space Agency

This NASA Hubble Space Telescope image of the Antennae galaxies is the sharpest yet of this merging pair of galaxies. NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA [View Larger Image]May 9,2008 The Antennae Galaxies are among the closest known merging systems. Also known as NGC 4038 and NGC 4039, the two began interacting a few hundred million years ago, creating one of the most impressive sights in the night sky. They are used by scientists as a standard against which to validate theories of galactic evolution.An international group of scientists led by Ivo Saviane from the European Southern Observatory used Hubble's Advanced Camera for Surveys and Wide Field Planetary Camera 2 to observe individual stars spawned by the colossal cosmic collision in the Antennae Galaxies. By measuring the colors and brightnesses of red giant stars in the system, the scientists found that the Antennae are much closer than previously thought: 45 million light-years instead of the previous best estimate of 65 million light-years.The team targeted a region in the relatively quiescent outer regions in the southern tidal tail, away from the active central regions. This tail consists of material thrown from the main galaxies as they collided. The scientists needed to observe regions with older red giant stars to derive an accurate distance. Red giants are known to reach a standard brightness, which can then be used to infer their distance.The previous distance to the Antennae Galaxy was about 65 million light-years, although values as high as 100 million light years have been used. Our Sun is only 8 light-minutes away from us, so the Antennae Galaxies may seem rather distant. But if we consider that we already know of galaxies more than 10 billion light-years away, the two galaxies are really our neighbors.The new, smaller distance makes the Antennae Galaxies less extreme in terms of the physics needed to explain the observed phenomena. For instance, its infrared radiation is now that expected of a standard early merging event rather than that of an ultraluminous infrared galaxy. The size of the star clusters formed as a consequence of the Antennae merger now agree with those of clusters created in other mergers instead of being 1.5 times as large.The Antennae Galaxies are named for the two long tails of stars, gas and dust that resemble the antennae of an insect. These "antennae" are a physical result of the collision between the two galaxies. Studying their properties gives us a preview of what may happen when our Milky Way Galaxy collides with the neighboring Andromeda galaxy in several billion years.

Posted By Mikey Pannier

More at: http://www.astronomy.com/asy/default.aspx?c=a&id=6933

Pic of the day

2008 May 12

The M81 Galaxy Group Through the Integrated Flux Nebula
Credit & Copyright: Jordi Gallego

Explanation: Large galaxies and faint nebula highlight this deep image of the M81 Group of galaxies. First and foremost in the above wide-angle 12-hour exposure is the grand design spiral galaxy M81, the largest galaxy visible in the image. M81 is gravitationally interacting with M82 just below it, a big galaxy with an unusual halo of filamentary red-glowing gas. Around the image many other galaxies from the M81 Group of galaxies can be seen. Together with other galaxy congregates including our Local Group of galaxies and the Virgo Cluster of galaxies, the M81 Group is part of the expansive Virgo Supercluster of Galaxies. This whole galaxy menagerie is seen through the faint nebular glow of the Integrated Flux Nebula, a little studied complex of diffuse gas and dust clouds in our Milky Way Galaxy.

The Great Comet of 1997

Who remembers Hale-Bopp? You know, that big bright thing in the sky that cruised by 'bout 10 years ago. Oh man, what a 'beaut!

The Hale-Bopp comet was dubbed the "Great Comet of 1997" because it exceeded the predicted brightness estimated by astronomers. It was visible to the naked-eye for about 18 months. It was discovered in July of 1995 by Alan Hale and Thomas Bopp. As some of you may remember, certain people believed that their was an extraterrestrial spacecraft following the comet. This inspired the mass suicide of the Heaven's Gate cult (I almost joined).

Bopp did not own a telescope but discovered the irregular object through the eyepiece of his friends telescope. The comet became visible to the naked-eye in May of 1996. Hale-Bopp most likely made its last appearance about 4,200 years ago. Close approaches to Earth is rare because for Hale-Bopp because the orbit is almost perpendicular.

The most interesting scientific discovery that resulted from Hale-Bopp's passing was the result of the compositional analysis of the comets tail. On top of gas and dust, the comet had a third tail made up of sodium which extended about 50 million kilometers.

A Flat Universe

So back during one of the Classes Bernie started talking about weather the universe was flat or circular. Well here is an article talking about how evidence shows that the universe is flat based on the geometrical way that light moves, where it moves in a straight line unless it affected by gravity. With this then the universe will continue to expand at its rate and will not collapse on itself in and event called "the Big Crunch". The evidence used to help support this theory is base on measuring the faint background radiation and heat from the Big Bang. It is called Cosmic Microwave Background and is a tiny warmth that is given off by something that is just above absolute zero. Thus by looking at tiny fluctuations in this CMB, scientists are allowed to generate different models about the birth and expansion of the universe. With this process the hardest thing is differentiating between the CMB and interference from our galaxy, but even then it appears pretty well. These measurements of the CMB were taken from a project called Boomerang (Balloon Observation of Millimetric Extragalactic Radiation and Geophysics) and the data was gathered down in Antarctica. The measurements were taken from a highly sensitive telescope that was suspended from a balloon 131,000 feet above the ground and was airborne for 11 days between 1998 and 1999. Since then all the one billion measurements had to be taken and processed on the Cray T3E Supercomputer at the Lawrence Berkeley National Laboratory. By doing this it dropped process time from six years to three weeks. In the end they were able to conclude that the universe is flat and will expand forever because there is not enough matter to make it collapse on itself. It is believe though that for a short while after the big bang that the universe was curved because of how confined it was, but because how big and stretched out it has become the universe has become essentially flat.

http://news.bbc.co.uk/1/hi/sci/tech/727073.stm

Here it the Boomerang Website
http://cmb.phys.cwru.edu/boomerang/index.html

Ol' Comet Halley

As I was growing up, I remember my parents making references to a comet called Halley. I knew that it had passed Earth around the time that I was born, so I have decided to do more research.

Halley's Comet last approached Earth in 1986. It is the most popular of periodic comets and is viewable to us about every 75 years. Periodic comets are defined as comets that have orbits that return the comet near to Earth's view within 200 years of the last pass. However, this pass was not the best. With added light pollution, only certain people, mainly those in the southern hemisphere, were able to catch a glimpse of this interesting occurrence.

Halley's Comet is popular because it can be seen by the naked-eye. Therefore, it is referred to as a naked-eye comet. Although many people were not able to see the comet, advancements in technology allowed astronomers to send spacecrafts equipped with telescopes to get a better view of the comet. Given its small orbit, it should reappear around 2061.

Record-Setting Laser

Scientists at the University of Konstanz in Germany and the National Institute of Standards and Technology (NIST) have demonstrated an ultrafast laser that offers a record combination of high speed, short pulses and high average power. The same NIST group also has shown that this type of laser, when used as a frequency comb—an ultraprecise technique for measuring different colors of light—could boost the sensitivity of astronomical tools searching for other Earthlike planets as much as 100 fold.
Among its applications, the new laser can be used in searches for planets orbiting distant stars. Astronomers look for slight variations in the colors of starlight over time as clues to the presence of a planet orbiting the star. The variations are due to the small wobbles induced in the star’s motion as the orbiting planet tugs it back and forth, producing minute shifts in the apparent color (frequency) of the starlight. Currently, astronomers’ instruments are calibrated with frequency standards that are limited in spectral coverage and stability. Frequency combs could be more accurate calibration tools, helping to pinpoint even smaller variations in starlight caused by tiny Earthlike planets.

Full article: http://www.sciencedaily.com/releases/2008/05/080505224136.htm

Antennae Galaxies move closer

The Antennae Galaxies are among the closest known merging systems. Also known as NGC 4038 and NGC 4039, the two began interacting a few hundred million years ago, creating one of the most impressive sights in the night sky. They are used by scientists as a standard against which to validate theories of galactic evolution. An international group of scientists led by Ivo Saviane from the European Southern Observatory used Hubble's Advanced Camera for Surveys and Wide Field Planetary Camera 2 to observe individual stars spawned by the colossal cosmic collision in the Antennae Galaxies. By measuring the colors and brightnesses of red giant stars in the system, the scientists found that the Antennae are much closer than previously thought: 45 million light-years instead of the previous best estimate of 65 million light-years. The team targeted a region in the relatively quiescent outer regions in the southern tidal tail, away from the active central regions. This tail consists of material thrown from the main galaxies as they collided. The scientists needed to observe regions with older red giant stars to derive an accurate distance. Red giants are known to reach a standard brightness, which can then be used to infer their distance. The previous distance to the Antennae Galaxy was about 65 million light-years, although values as high as 100 million light years have been used. Our Sun is only 8 light-minutes away from us, so the Antennae Galaxies may seem rather distant. But if we consider that we already know of galaxies more than 10 billion light-years away, the two galaxies are really our neighbors. The new, smaller distance makes the Antennae Galaxies less extreme in terms of the physics needed to explain the observed phenomena. For instance, its infrared radiation is now that expected of a standard early merging event rather than that of an ultraluminous infrared galaxy. The size of the star clusters formed as a consequence of the Antennae merger now agree with those of clusters created in other mergers instead of being 1.5 times as large. The Antennae Galaxies are named for the two long tails of stars, gas and dust that resemble the antennae of an insect. These "antennae" are a physical result of the collision between the two galaxies. Studying their properties gives us a preview of what may happen when our Milky Way Galaxy collides with the neighboring Andromeda galaxy in several billion years.

Why is it Just the US in SETI?

There is an interesting editorial about why the US is the only major player in SETI research. He talks about budgeting, and other nations lack of concern for ambiguous institutions like SETI. Check it out here.

First Ever Space Lawyer!

After taking BUS 290 Law & Ethics I thought I had a decent understanding of the legal system. Apparantly I missed the part about space lawyers! The first ever space law degree was recently handed out to Michael Dodge at Ole Miss. He said he can use the degree to handle disputes amongst astronauts at the ISS, shot down debris, etc. Seems like space does need some regulation. Check it out here.

Top 10 Martian Landings!

Space.com chronicles the ten best (and worst) Martian landings! It's actually pretty interesting, and it goes through each landing giving you pics and some descriptions of what happened on the missions. Go check it out here!

Iron 'snow' helps maintain Mercury's magnetic field

Researchers are closer to understanding how planetary cores evolve.

by James E. Kloeppel/University of Illinois

Mariner 10 also discovered that Mercury has a weak magnetic field, about one percent as strong as Earth's. NASA [View Larger Image]
May 8, 2008
New scientific evidence suggests that deep inside Mercury, iron "snow" forms and falls toward the center of the planet, much like snowflakes form in Earth's atmosphere and fall to the ground.

The movement of this iron snow could be responsible for Mercury's mysterious magnetic field, say researchers from the University of Illinois and Case Western Reserve University. In a paper published in the April issue of Geophysical Research Letters, the scientists describe laboratory measurements and models that mimic conditions believed to exist within Mercury's core.

"Mercury's snowing core opens up new scenarios where convection may originate and generate global magnetic fields," said University of Illinois geology professor Jie (Jackie) Li. "Our findings have direct implications for understanding the nature and evolution of Mercury's core, and those of other planets and moons."

Mercury is the innermost planet in our solar system and, other than Earth, the only terrestrial planet that possesses a global magnetic field. Discovered in the 1970s by NASA's Mariner 10 spacecraft, Mercury's magnetic field is about 100 times weaker than Earth's.

Made mostly of iron, Mercury's core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet's magnetic field.

"Recent Earth-based radar measurements of Mercury's rotation revealed a slight rocking motion that implied the planet's core is at least partially molten," said Illinois graduate student Bin Chen, the paper's lead author. "But, in the absence of seismological data from the planet, we know very little about its core."

To better understand the physical state of Mercury's core, the researchers used a multi-anvil apparatus to study the melting behavior of an iron-sulfur mixture at high pressures and high temperatures.

In each experiment, an iron-sulfur sample was compressed to a specific pressure and heated to a specific temperature. The sample was then quenched, cut in two, and analyzed with a scanning electron microscope and an electron probe microanalyzer.

As the molten, iron-sulfur mixture in the outer core slowly cools, iron atoms condense into cubic "flakes" that fall toward the planet's center, Chen said. As the iron snow sinks and the lighter, sulfur-rich liquid rises, convection currents are created that power the dynamo and produce the planet's weak magnetic field.

Mercury's core is most likely precipitating iron snow in two distinct zones, the researchers said. This double-snow state may be unique among the terrestrial planets and Earth-like moons in our solar system.

"Our findings provide a new context into which forthcoming observational data from NASA's MESSENGER spacecraft can be placed, "Li said. "We can now connect the physical state of our innermost planet with the formation and evolution of terrestrial planets in general."

http://www.astronomy.com/asy/default.aspx?c=a&id=6927

The Gamma-Ray Large Area Space Telescope (GLAST) Mission - 5.16.2008

On May 16th, scientists plan to launch a new space mission that will study gamma-rays in space in hopes of finding pulsars and supermassive black holes in space.

Click here for full article

Black Holes, Flares, And Pancakes

After our discussions the last two days in class, this article on black holes and flares (see below) is interesting. This observation from apr. 21 led to a couple interesting articles about stars that orbit too close to black holes becoming flat like pancakes (click here or here for more about that). I think we were just starting to touch on this kind of thing at the end of class on Wednesday.

X-Ray Flare Echo Reveals Supermassive Black Hole Torus

Written by Ian O'Neill

The light echo of an X-ray flare from the nucleus of a galaxy has been observed. The flare almost certainly originates from a single star being gravitationally ripped apart by a supermassive black hole in the galactic core. As the star was being pulled into the black hole, its material was injected into the black hole accretion disk, causing a sudden burst of radiation. The resulting X-ray flare emission was observed as it hit local stellar gases, producing the light echo. This event gives us a better insight to how stars are eaten by supermassive black holes and provides a method to map the structure of galactic nuclei. Scientists now believe they have observational evidence for the elusive molecular torus that is thought to surround active supermassive black holes.... click here for full article

Magic of Satellites

Satellite captures cyclone damage

NASA's Terra satellite shows aftermath of floods in Burma.

by Rebecca Lindsey

NASA's Terra satellite captured this image of the Myanmar coast on May 5, 2008, showing the devastation of flooding caused by Tropical Cyclone Nargis. NASA/MODIS Rapid Response Team [View Larger Image]

May 7, 2009
The first cyclone of the 2008 season in the northern Indian Ocean was a devastating one for Burma. According to reports from Accuweather.com, Cyclone Nargis made landfall with sustained winds of 130 mph and gusts of 150-160 mph, the equivalent of a strong category 3 or minimal category 4 hurricane. News reports stated that several thousand people have been killed, and thousands more were missing as of May 5.

Flood water can be difficult to see in photo-like satellite images, particularly when the water is muddy. This pair of images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite use a combination of visible and infrared light to make floodwaters obvious. Water is blue or nearly black, vegetation is bright green, bare ground is tan, and clouds are white or light blue.

On April 15, rivers and lakes are sharply defined against a backdrop of vegetation and fallow agricultural land. The Irrawaddy River flows south through the left-hand side of the image, splitting into numerous distributaries known as the Mouths of the Irrawaddy. The wetlands near the shore are a deep blue green. Cyclone Nargis came ashore across the Mouths of the Irrawaddy and followed the coastline northeast.

The entire coastal plain is flooded in the May 5 image. The fallow agricultural areas appear to have been especially hard hit. For example, Yangôn (population over 4 million) is almost completely surrounded by floods. Several large cities (population 100,000-500,000) are in the affected area. Muddy runoff colors the Gulf of Martaban turquoise.

The high-resolution image provided above is at MODIS' maximum spatial resolution (level of detail) of 250 meters per pixel. The MODIS Rapid Response Team provides twice-daily images of the region in additional resolutions and formats, including photo-like natural color.







Posted by mikey pannier

more at : http://www.astronomy.com/asy/default.aspx?c=a&id=6925

Closer encounter: Nasa plans landing on 40m-wide asteroid traveling at 28,000 MPH

It was once considered the most dangerous object in the universe, heading for Earth with the explosive power of 84 Hiroshimas. Now an asteroid called 2000SG344, a lump of rock barely the size of a large yacht, is in the spotlight again, this time as a contender for the next giant leap for mankind.

Nasa engineers have identified the 1.1m tonne asteroid, which in 2000 was given a significant chance of slamming into Earth, as a potential landing site for astronauts, ahead of the Bush administration's plans to venture deeper into the solar system with a crewed voyage to Mars.

The mission - the first to what officials call a Near Earth Object (NEO) - is being floated within the US space agency as a crucial stepping stone to future space exploration.

More here: http://www.guardian.co.uk/science/2008/may/07/starsgalaxiesandplanets.spaceexploration

-Ryan

National Geographic on the Moon & Earthquakes & More

A couple weeks ago, I ended up watching this show called "Moon Mysteries" on the National Geographic Channel. It was particularly interesting because it was after we had finished our lessons on the moon, but what was especially interesting was the theorizing on the moon's role in causing earthquakes and volcanic eruptions. Theorists argue that the gravity of the moon can cause tectonic plates to move in some situations, similarly to the effect the moon's gravitational pull has on the Earth's tides, and thus causes earthquakes and volcanic eruptions. A San Fransisco scientist has even been able to successfully predict major earthquakes based on this theory according to the show.

If you're interested in the episode which says much more about the moon than just this, then check out the listings for the National Geographic Channel or consider downloading this video on the moon from here. Otherwise, here's a simple article from 2004 about how the moon may affect earthquakes and volcanic eruptions on Earth.

2 Moons for Earth?

Lagrange theory was briefly mentioned in one of the classes or lab the other day. This article discusses the idea of a second moon for earth at one point in time based on the idea of the Lagrange points. It's interesting to consider the idea of a second moon for Earth, as well as to hear more about Lagrange after it was mentioned in class at one point.

Here's the link to the article.

Jupiter's Rings Are Shaped By Interplay of Sunlight And Shadow

Scientists from the University of Maryland and the Max-Planck Institute for Solar System Research in Germany appear to have solved a long-standing mystery about the cause of anomalies in Jupiter's gossamer rings.

In a new study published in the May 1 issue of Nature, they report that a faint extension of the outermost ring beyond the orbit of Jupiter's moon Thebe, and other observed deviations from an accepted model of ring formation, result from the interplay of shadow and sunlight on dust particles that make up the rings.
"It turns out that the outer ring's extended boundary and other oddities in Jupiter's rings really are 'made in the shade,'" said Douglas Hamilton, a professor of astronomy at the University of Maryland. " As they orbit about the planet, dust grains in the rings alternately discharge and charge when they pass through the planet's shadow. These systematic variations in dust particle electric charges interact with the planet's powerful magnetic field. As a result small dust particles are pushed beyond the expected ring outer boundary, and very small grains even change their inclination, or orbital orientation, to the planet."

Full article: http://www.sciencedaily.com/releases/2008/04/080430134305.htm

Goodbye Star Buddy

Astronomers at the Harvard-Smithsonian Center for Astrophysics discovered a star fleeing our galaxy. They believe that this speedy exit was presumably caused by the star encountering the Milky Way Galaxy’s central black hole. The astronomers estimate that the star has a speed of at least 1.5 million miles per hour.

This is the first star moving fast enough to actually break away from the limits of the Milky Way. The extreme gravity caused by the black hole of our galaxy’s center is necessary to cause speeds of this kind from an interstellar object. With a velocity twice as fast as any we have seen before from an escaping object, it is clear that it will be able to travel far beyond the reaches of our galaxy.

Also, because the star is made up of more heavy metals than those farther away from the center of the galaxy, astronomers concluded, after analyzing its path and velocity, that the star must be less than 80 million years old and have originated near the center of the Milky Way.

Want more details? Go to www.spaceflightnow.com

New Breed of Star Discovered

The University of Texas astronomers have discovered a pulsating carbon white dwarf. The two types of white dwarfs formerly known to exist have an outer layer of helium or an outer layer of hydrogen.

However, stars lacking the hydrogen and helium layers were found. These stars seem to be shredded down to their carbon layer. Leaving this layer exposed has revealed the most enormous white dwarf stars, too tiny to terminate their existence in a supernova explosion.

Pulsations in these stars may assist astronomers understanding of the carbon white dwarfs’ output which may produce better analysis of their interior.

“National Science Foundation astronomer Michael Briley said, ‘This will allow us to probe the white dwarf's interior, which in turn should help us solve the riddle of where the carbon white dwarfs come from and what happens to their hydrogen and helium.’”

Summarized from Astronomy Now Online: http://www.astronomynow.com/Astronomersdiscovernewbreedofstar.html

I typed this baby up on Monday evening. Sorry about the redundancy with the full article already being submitted.

Cosimic Spider Man

A cosmic spider web is unraveled

Long-sought baryonic matter connects two galaxies.

Max Planck Institute for Extraterrestrial Physics

A bridge of hot gas connects two clusters of galaxies. Max Planck Institute [View Larger Image]

May 6, 2008
The composition of the universe still puzzles astronomers. Over 90 percent consists of unknown matter. Just four percent is the normal material of which humans are made — the so-called baryonic matter. Even this small part is not yet completely understood.

A team of astrophysicists from the Max Planck Institute for Extraterrestrial Physics (MPE) and the European Southern Observatory (ESO), and two institutes in the Netherlands have found evidence of the missing baryons in a bridge-like filament connecting two clusters of galaxies.

The Universe is constructed like an oversized spider web. All visible material is arranged along the filamentary structure of the dark matter. On its threads and knots, this web holds gigantic chunks of baryonic matter, which are made of quarks and leptons.

Astronomers knew for a long time that the pieces of the cosmological puzzle must be hidden somewhere. Tracing and capturing this observable component in the universe will help us learn more about dark material.

The missing part of the baryonic matter is thought to be a hot, ultra-thin gas haze of very low density between larger structures. Scientists from SRON Netherlands Institute for Space Research observed the clusters of galaxies Abell 222 and Abell 223, which are connected by a filament.

The gas they found is probably the hottest and densest part of the diffuse gas which constitutes half of the missing baryons in the universe.

This is the first time that scientists have seen the bridge of gas connecting two clusters of galaxies. "So far, we could only see the clusters, the dense knots of the web. Now, we are starting to see the connecting wires of the immense cosmic spider web," says MPE astrophysicist Aurora Simionescu.


more at: http://www.astronomy.com/asy/default.aspx?c=a&id=6923

Posted by mikey pannier

Astronomers Discover New Type Of Pulsating White Dwarf Star

ScienceDaily (May 1, 2008) — University of Texas at Austin astronomers Michael H. Montgomery and Kurtis A. Williams, along with graduate student Steven DeGennaro, have predicted and confirmed the existence of a new type of variable star, with the help of the 2.1-meter Otto Struve Telescope at McDonald Observatory. Called a "pulsating carbon white dwarf," this is the first new class of variable white dwarf star discovered in more than 25 years. Because the overwhelming majority of stars in the universe--including the sun--will end their lives as white dwarfs, studying the pulsations (i.e., variations in light output) of these newly discovered examples gives astronomers a window on an important end point in the lives of most stars.

A white dwarf star is the leftover remnant of a sun-like star that has burned all of the nuclear fuel in its core. It is extremely dense, packing half to 1.5 times the sun's mass into a volume about the size of Earth. Until recently, there were thought to be two main types of white dwarfs: those with an outer layer of hydrogen (about 80 percent of white dwarfs), and those with an outer layer of helium, whose hydrogen shells have somehow been stripped away (the other 20 percent).

Last year, University of Arizona astronomers Patrick Dufour and James Liebert discovered a third type of white dwarf star. For reasons that are not understood, these "hot carbon white dwarfs" have had both their hydrogen and helium shells stripped off, leaving their carbon layer exposed. Astronomers suspect that these could be among the most massive white dwarfs of all, the remnants of stars slightly too small to end their lives in a supernova explosion.

After these new carbon white dwarfs were announced, Montgomery calculated that pulsations in these stars were possible. Pulsating stars are of interest to astronomers because the changes in their light output can reveal what goes on in their interiors--similar to the way geologists study seismic waves from earthquakes to understand what goes on in Earth's interior. In fact, this type of star-study is called "asteroseismology."

So, Montgomery and Williams' team began a systematic study of carbon white dwarfs with the Struve Telescope at McDonald Observatory, looking for pulsators. DeGennaro discovered that a star about 800 light-years away in the constellation Ursa Major, called SDSS J142625.71+575218.3, fits the bill. Its light intensity varies regularly by nearly two percent about every eight minutes.

"The discovery that one of these stars is pulsating is remarkably important," said NSF astronomer Michael Briley. "This will allow us to probe the white dwarf's interior, which in turn should help us solve the riddle of where the carbon white dwarfs come from and what happens to their hydrogen and helium."

The star lies about ten degrees east northeast of Mizar, the middle star in the handle of the Big Dipper. This white dwarf has about the same mass as our Sun, but its diameter is smaller than Earth's. The star has a temperature of 35,000 degrees Fahrenheit (19,500 C), and is only 1/600th as bright as the Sun.

None of the other stars in their sample were found to pulsate. Given the masses and temperatures of the stars in their sample, SDSS J142625.71+575218.3 is the only one expected to pulsate, based on Montgomery's calculations.

The astronomers speculate that the pulsations are caused by changes in the star's carbon outer envelope as the star cools down from its formation as a hot white dwarf. The ionized carbon atoms in the star's outer layers return to a neutral state, triggering the pulsations.

There is a chance that the star's variations might have another cause. Further study is needed, the astronomers say. Either way, studying these stars will shed light on the unknown process that strips away their surface layers of hydrogen and helium to lay bare their carbon interiors.

The discovery is published in Astrophysical Journal Letters, May 1. This research was funded by the National Science Foundation and the Delaware Asteroseismic Research Center.

Searching The Heavens For Pulsars And Supermassive Black Holes

ScienceDaily (May 4, 2008) — A new space mission, due to launch this month, is going to shed light on some of the most extreme astrophysical processes in nature - including pulsars, remnants of supernovae, and supermassive black holes. It could even help us comprehend the origin and distribution of dark matter, write three scientists currently preparing for the GLAST mission from NASA's Goddard Space Flight Centre in Greenbelt, Maryland, USA, in Physics World.

The Gamma-Ray Large Area Space Telescope (GLAST), to be launched on 16 May 2008, is a four-tonne observatory packed with state-of-the-art particle detectors that will study the gamma-ray sky in unprecedented detail.

Gamma rays are a form of electromagnetic radiation with much higher frequency and energy than visible light, UV light or even X-rays. Having such high energy, gamma rays are hard to collect and focus in the way that a conventional telescope does with visible light. Gamma rays are therefore the most difficult form of electromagnetic radiation to track in space.

Whereas visible light reveals thousands of stars and individual planets moving slowly across the sky, studying the skies at gamma-ray frequencies reveals a much weirder picture of space.

Gamma rays are not produced by hot, glowing objects, but from collisions between charged, very rapidly moving, particles and matter or light. The high frequency photons that are emitted from these collisions provide a glimpse of the most extreme astrophysical processes known.

Black holes, for example, accelerate matter to produce extreme energies in active galaxies. The gamma rays emitted in these scenarios have the equivalent energy to that of all the stars in an entire galaxy over all wavelengths.

Until now, however, existing ground-based gamma-ray detectors have not been sophisticated enough to measure these emissions in any detail over long periods. The astrophysicists cite looking for signatures of as-yet-unknown fundamental physical processes as a key reason for embarking on this project.

Julie McEnery, Steve Ritz and Neil Gehrels of NASA's Goddard Space Centre, write, "We expect GLAST to have a large impact on many areas of astrophysics but what is most exciting are the surprises: with any luck, the greatest GLAST science has not even been thought of yet."

Spacecraft to the Sun

NASA calls on the APL to send a probe to the brightest star in our solar system.

Provided by the Johns Hopkins University APL

The Johns Hopkins University Applied Physics Laboratory (APL) is sending a spacecraft closer to the Sun than any probe has ever gone — and what it finds could revolutionize what we know about our star and the solar wind that influences everything in our solar system.

NASA has tapped APL to develop the ambitious Solar Probe mission, which will study the streams of charged particles the Sun hurls into space from a vantage point within the Sun's corona — its outer atmosphere — where the processes that heat the corona and produce solar wind occur. At closest approach Solar Probe would zip past the Sun at 125 miles per second, protected by a carbon-composite heat shield that must withstand up to 2,600° F and survive blasts of radiation and energized dust at levels not experienced by any previous spacecraft.

Experts in the U.S. and abroad have grappled with this mission concept for more than 30 years, running into seemingly insurmountable technology and budgetary limitations. But in February an APL-led team completed a Solar Probe engineering and mission design study at NASA's request, detailing just how the robotic mission could be accomplished. The study team used an APL-led 2005 study as its baseline, but then significantly altered the concept to meet challenging cost and technical conditions provided by NASA.

"We knew we were on the right track," says Andrew Dantzler, Solar Probe project manager at APL. "Now we've put it all together in an innovative package; the technology is within reach, the concept is feasible and the entire mission can be done for less than $750 million [in fiscal 2007 dollars], or about the cost of a medium-class planetary mission. NASA decided it was time."

APL will design and build the spacecraft, on a schedule to launch in 2015. The compact, solar-powered probe would weigh about 1,000 pounds; preliminary designs include a 9-foot-diameter, 6-inch-thick, carbon-foam-filled solar shield atop the spacecraft body. Two sets of solar arrays would retract or extend as the spacecraft swings toward or away from the sun during several loops around the inner solar system, making sure the panels stay at proper temperatures and power levels. At its closest passes the spacecraft must survive solar intensity more than 500 times what spacecraft experience while orbiting Earth.

Solar Probe will use seven Venus flybys over nearly 7 years to gradually shrink its orbit around the Sun, coming as close as 4.1 million miles (6.6 million kilometers) to the Sun, well within the orbit of Mercury and about eight times closer than any spacecraft has come before.

Solar Probe will employ a combination of in-place and remote measurements to achieve the mission's primary scientific goals: determine the structure and dynamics of the magnetic fields at the sources of solar wind; trace the flow of energy that heats the corona and accelerates the solar wind; determine what mechanisms accelerate and transport energetic particles; and explore dusty plasma near the sun and its influence on solar wind and energetic particle formation. Details will be spelled out in a Solar Probe Science and Technology Definition Team study that NASA will release later this year. NASA will also release a separate Announcement of Opportunity for the spacecraft's science payload.

"Solar Probe is a true mission of exploration," says Dr. Robert Decker, Solar Probe project scientist at APL. "For example, the spacecraft will go close enough to the Sun to watch the solar wind speed up from subsonic to supersonic, and it will fly though the birthplace of the highest energy solar particles. And, as with all missions of discovery, Solar Probe is likely to raise more questions than it answers."

APL's experience in developing spacecraft to study the sun-Earth relationship - or to work near the Sun — includes ACE, which recently marked its 10th year of sampling energetic particles between Earth and the sun; TIMED, currently examining solar effects on Earth's upper atmosphere; the twin STEREO probes, which have snapped the first 3-D images of explosive solar events called coronal mass ejections; and the Radiation Belt Storm Probes, which will examine the regions of energetic particles trapped by Earth's magnetic field.

Solar Probe will be fortified with heat-resistant technologies developed for APL's MESSENGER spacecraft, which completed its first flyby of Mercury in January and will begin orbiting that planet in 2011. Solar Probe's solar shield concept was partially influenced by designs of MESSENGER's sunshade.

Spot Elusive Mercury

The innermost planet makes its best appearance of 2008 in early May.

Michael E. Bakich

The Moon joins Mercury May 6, during the innermost planet’s best evening apparition of 2008. Through binoculars, you should also pick out the Pleiades star cluster. Be sure to find an observing location with an unobstructed western horizon. Astronomy: Roen Kelly [View Larger Image]

May 1, 2008
Mercury — the closest planet to the Sun — makes its best evening appearance of the year this month. Mercury looks about as bright as it ever does, with the view made picturesque May 2 by its location just 2° south of the Pleiades star cluster (M45), which lies in the constellation Taurus the Bull.

At its brightest in May, the innermost planet shines at magnitude –0.9. Brighter than any star through May 8, Mercury makes a stunning sight above the west-northwestern horizon. A 2-day-old crescent Moon joins the scene May 6, when it lies less than 3° to Mercury's upper right. You'll need clear skies and sharp vision to detect the Moon. Its slender crescent will be only 4 percent illuminated.

For the best views, use binoculars just as twilight falls. Camera owners might want to try shooting some images. The most pleasing contain foreground objects — trees, a water tower, or a windmill, for instance — which enhance the scene. They form great silhouettes and add to an image's impact.

A telescope easily reveals Mercury's phase, which shrinks to half-lit by May 8. It then stands 8° north of Aldebaran, Taurus' brightest star. Although Aldebaran is a 1st-magnitude star, it nevertheless shines a full magnitude fainter than Mercury.

Astronomy Senior Editor Michael E. Bakich explains what's happening: "When Mercury is as far east of the Sun as it can get (called greatest eastern elongation), we see it as an evening star low in the west," he said. "When it's west of the Sun, we view it as a morning star in the east before sunrise."

Some elongations are better than others because of Earth's tilt and the stretched-out nature of Mercury's orbit. Even at its farthest from the Sun, Mercury appears no more than 28º away.

Mercury reaches its greatest elongation May 13/14, when it lies 22° east of the Sun and sets 2 hours after our star. Still located in Taurus, Mercury then reveals a 37-percent-illuminated disk through a telescope. If you've followed it from the start of May, you'll notice the planet now shines more than a magnitude fainter. Still, it outshines all but two current nighttime stars.

Mercury continues to dim all month. By the 18th, it equals Aldebaran in brightness, and it appears only half that bright by the 22nd. Its angular distance from the Sun declines as well, making the planet harder to see after this date.

NASA returning to the moon

WASHINGTON (AP) - The NASA inspector general says the space agency is breaking the law by allowing conflicts of interest on a board overseeing the building of a new spaceship to return astronauts to the moon.

The board is set up to review NASA's new Orion capsule. The panel is loaded with employees of the contractors it is supposed to scrutinize, the inspector general report says.

The report says the board chairman and five other members work for contractors hired by NASA for the multi-billion-dollar space shuttle replacement program. Four of the six are also stockholders in firms making money off the NASA project, the report says.

-Ryan

Ancient Mars Delta

Martian river delta

The European Space Agency's Mars Express captured this view with its High Resolution Stereo Camera. This region, known as Nepenthes Mensae, was once a river delta on the Red Planet. The orbiter captured this image January 22, 2008.

The data was acquired in the region lying at approximately 3° north and 121° east
More at: http://www.astronomy.com/asy/default.aspx?c=pod&id=186

Posted By Mikey Pannier

Cracks In The Foundation: Fundamental Geological Assumption Relating To Planet Earth Not Quite True

ScienceDaily (Apr. 29, 2008) — Chondritic meteorites have a similar chemical composition to the sun and are therefore reliable witnesses as to what the solar nebula, from which the planets formed, was composed of. This can be used to deduce what the Earth consists of chemically. However, ETH Zurich researchers have now discovered that strictly speaking this fundamental geological assumption is not true.

More?
http://www.sciencedaily.com/releases/2008/04/080428081732.htm

Ultra-dense Galaxies Found In Early Universe

ScienceDaily (Apr. 29, 2008) — A team of astronomers looking at the universe's distant past found nine young, unusually compact galaxies, each weighing in at 200 billion times the mass of the Sun. These young galaxies are the equivalent of a human baby that is 20 inches long, yet weighs 180 pounds.

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http://www.sciencedaily.com/releases/2008/04/080429095054.htm

ASTRONOMY.COM

Will meteors from Halley's comet surge?
A possible flurry of "shooting stars" makes this year's Eta Aquarid meteor shower worth a look.
Francis Reddy

Eta Aquarid Meteors will pepper the sky before dawn May 5. With the Moon at new phase, observing conditions should be ideal. Astronomy: Roen Kelly
April 29, 2008 Be on the lookout for a rush of meteors before dawn Monday morning. That's when the annual Eta Aquarid meteor shower reaches maximum activity. Seeing the shower with no interference from the Moon is nice, but there's a possible bonus. Astronomers think the Eta Aquarids could produce more than twice the usual number of meteors. Meteors are fleeting fiery trails — "shooting stars" — that occur as small solid particles burn up in Earth's atmosphere. Comets shed dust as ice boils off their surfaces and litter their orbits with debris. Meteor showers result when Earth grazes a comet's dusty path and sweeps up some of these particles. Dust shed by Comet 1P/Halley creates the Eta Aquarid shower, so named because the meteors seem to emanate from a common point, or radiant, near the star Eta in the constellation Aquarius. Meteor-watching is a minimalist activity. No equipment is required — skygazers just need to know when and where to look. Dress warmly, relax in a comfortable chair, and keep an eye on the southeastern sky. It's kind of like fishing.
In Halley's dustAstronomers give a shower's meteor rate using numbers that express the number of meteors seen each hour by an observer viewing under a clear, dark sky when the radiant is overhead. In most years, by this measure, the Eta Aquarid shower rates 30 meteors per hour. But the radiant never gets overhead before dawn, so observers typically will see far fewer meteors.This year, though, the rate could more than double. Studies suggest the shower's rates rise and fall in a 12-year cycle. This period hints that Jupiter, the solar system's largest planet, is affecting the debris that creates the shower.Jupiter orbits the Sun in just under 12 years. Every time it passes closest to the Eta Aquarid track, the orbiting particles feel an extra-strong tug. This results in a wavy track that sometimes places extra dust in Earth's way.
Catch a falling starThe Eta Aquarid shower is best for Southern Hemisphere observers, and the view gets worse the farther north you go. In the United States, the radiant stands only about 15° high in the southeast at 4 A.M. local daylight time. This low altitude will cut the number of visible meteors significantly. Even so, observers can expect a nice show.The shower produces pleasingly fast and often bright meteors. About 30 percent of the meteors leave behind dimly glowing trails called persistent trains. Some can be seen for as long as a minute. Although the radiant's low altitude reduces the number of observable meteors for northern observers, there is compensation. Eta Aquarid meteors tend to follow long paths across the sky.
Eta Aquarid meteor shower fast facts
The Eta Aquarids are the first of two annual showers produced by Halley's Comet. The other is the Orionid shower in late October.
Astronomers discovered the shower in 1870 and linked it to Comet Halley just six years later.
Its meteors are among the fastest, entering the atmosphere at 151,000 mph (243,000 km/h).
The meteors average magnitude 3. The brighter ones display a yellowish color.

Posted By Mikey Pannier