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Mars CO2 Clouds Tied to Atmospheric Waves

February 14, 2012 Leave a comment

On 4 March 1997 the Mars Pathfinder lander fell through the thin Martian atmosphere. During its descent, instrumentation aboard the lander recorded the changing atmospheric temperature, pressure, and density. Within this atmospheric profile, researchers identified anomalous cold air packets within the Martian mesosphere (60–90 kilometers, or 37–56 miles, altitude). Later orbital measurements confirmed the existence of these cold pockets, adding to the mystery the detection of clouds made from carbon dioxide. Researchers in 1998 suspected that the cold air pockets, and thus conditions favorable for carbon dioxide condensation, were the product of atmospheric gravity waves in the Martian mesosphere. That hypothesis remained largely untested until advances in global- and intermediate-scale atmospheric models allowed Spiga et al. to confirm that gravity waves were a potentially viable mechanism to produce the necessary mesospheric conditions.

The authors find that gravity waves, produced in the model when wind rose up and over a mountain, could cause temperature variations in the mesosphere of up to 12 degrees Kelvin (21 degrees Fahrenheit). They suggest that this amount of cooling, if it happens to coincide with a larger atmospheric temperature shift, could push mesospheric temperatures a few degrees below the -80 degrees Celsius (-112 degrees Fahreneheit) condensation point of carbon dioxide. Combining the results of their smaller-scale model with those of a Martian general circulation model, the authors find that they can account for carbon dioxide cloud distribution patterns consistent with observational records.

Full Story: http://www.agu.org/news/press/jhighlight_archives/2012/2012-02-14.shtml#two

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Categories: Astronomy, Mars, Solar System Tags: , ,

Globular Star Clusters Survived 13-Gyr-Old Massacre

February 14, 2012 Leave a comment

Our Milky Way galaxy is surrounded by some 200 compact groups of stars, containing up to a million stars each. These globular clusters are almost as old as the universe itself and hold valuable information on how the first generations of stars and galaxies formed. Now a team of astronomers from Germany and the Netherlands have conducted a novel type of computer simulation that looked at how they were born – and they find that these giant clusters of stars are the only survivors of a 13 billion year-old massacre that destroyed many of their smaller siblings. The new work, led by Dr Diederik Kruijssen of the Max Planck Institute for Astrophysics in Garching appears in a paper in the journal Monthly Notices of the Royal Astronomical Society.

Globular star clusters have a remarkable characteristic: the typical number of stars they contain appears to be about the same throughout the Universe. This is in contrast to much younger stellar clusters, which can contain almost any number of stars, from fewer than 100 to many thousands. The team of scientists proposes that this difference can be explained by the conditions under which globular clusters formed early on in the evolution of their host galaxies.

The researchers ran simulations of isolated and colliding galaxies, in which they included a model for the formation and destruction of stellar clusters. When galaxies collide, they often generate spectacular bursts of star formation (“starbursts”) and a wealth of bright, young stellar clusters of many different sizes. As a result it was always thought that the total number of star clusters increases during starbursts. But the Dutch-German team found the opposite result in their simulations.

Full Story: http://www.mpa-garching.mpg.de/mpa/institute/news_archives/news1202_aaa/news1202_aaa-en.html

NASA Reaches Higher With Fiscal Year 2013 Budget Request

February 14, 2012 Leave a comment

NASA announced Monday a $17.7 billion budget request for fiscal year 2013 supporting an ambitious program of space exploration that will build on new technologies and proven capabilities to expand America’s reach into the solar system.

Despite a constrained fiscal environment, the NASA FY13 budget continues to implement the space science and exploration program agreed to by President Obama and a bipartisan majority in Congress, laying the foundation for ground-breaking discoveries here on Earth and in deep space, including new destinations, such as an asteroid and Mars by 2035.

“This budget in-sources jobs, creates capabilities here at home — and strengthens our workforce, all while opening the next great chapter in American exploration,” NASA Administrator Charles Bolden said. “And as we reach for new heights in space, we’re creating new jobs right here on Earth, helping to support an economy that’s built to last.”

Full Story: http://www.nasa.gov/home/hqnews/2012/feb/HQ_12-051_2013_Budget.html

Intergalactic Space Is Filled with Dark Matter

February 14, 2012 Leave a comment

It is well known that there is a large amount of unseen matter called “dark matter” in the universe. It constitutes about 22 percent of the present-day universe while ordinary matter constitutes only 4.5 percent. An important question still remains – Where is most of the dark matter in the universe ?

Einstein’s theory of general relativity predicts that a light ray passing through near a massive object such as a galaxy is bent by the effect called “gravitational lensing”. For example, the effect causes the image of a distant galaxy to be deformed and brightened by an intervening galaxy. However the effect itself is very small and so cannot be easily detected for a single galaxy. Only recently, images of millions of galaxies from Sloan Digital Sky Survey (SDSS) made it possible to derive an averaged mass distribution around the galaxies. Earlier in 2010, an international research group led by Brice Menard then at University Toronto and Masataka Fukugita at IPMU used twenty four millions galaxy images from SDSS and successfully detected gravitational lensing effect caused by dark matter around the galaxies. From the result, they determined the projected matter density distribution over a distance of a hundred million light years from the center of the galaxies.

Full Story: http://www.ipmu.jp/node/1222

Planck Steps Closer to the Cosmic Blueprint

February 14, 2012 Leave a comment

Image Credits: ESA/Planck Collaboration; T. Dame et al., 2001

Image Credits: ESA/Planck Collaboration; T. Dame et al., 2001

ESA’s Planck mission has revealed that our Galaxy contains previously undiscovered islands of cold gas and a mysterious haze of microwaves. These results give scientists new treasure to mine and take them closer to revealing the blueprint of cosmic structure.

The new results are being presented this week at an international conference in Bologna, Italy, where astronomers from around the world are discussing the mission’s intermediate results.

These results include the first map of carbon monoxide to cover the entire sky. Carbon monoxide is a constituent of the cold clouds that populate the Milky Way and other galaxies. Predominantly made of hydrogen molecules, these clouds provide the reservoirs from which stars are born.

Full Story: http://www.esa.int/export/esaSC/SEM0FLYXHYG_index_0.html