vendredi 18 novembre 2011

Cygnus X-1: A Stellar Mass Black Hole











NASA - Chandra X-ray Observatory patch.

Nov. 18, 2011

 (Click on the image for enlarge)

On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist's illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system. Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star. The black hole pulls material from a massive, blue companion star toward it. This material forms a disk (shown in red and orange) that rotates around the black hole before falling into it or being redirected away from the black hole in the form of powerful jets.

A trio of papers with data from radio, optical and X-ray telescopes, including NASA's Chandra X-ray Observatory, has revealed new details about the birth of this famous black hole that took place millions of years ago. Using X-ray data from Chandra, the Rossi X-ray Timing Explorer, and the Advanced Satellite for Cosmology and Astrophysics, scientists were able to determine the spin of Cygnus X-1 with unprecedented accuracy, showing that the black hole is spinning at very close to its maximum rate. Its event horizon -- the point of no return for material falling towards a black hole -- is spinning around more than 800 times a second.

Using optical observations of the companion star and its motion around its unseen companion, the team also made the most precise determination ever for the mass of Cygnus X-1, of 14.8 times the mass of the Sun. It was likely to have been almost this massive at birth, because of lack of time for it to grow appreciably.

The researchers also announced that they have made the most accurate distance estimate yet of Cygnus X-1 using the National Radio Observatory's Very Long Baseline Array (VLBA). The new distance is about 6,070 light years from Earth. This accurate distance was a crucial ingredient for making the precise mass and spin determinations.

Read more/access all images: http://chandra.harvard.edu/photo/2011/cygx1/

Image, Text, Credits: X-ray: NASA/CXC; Optical: Digitized Sky Survey / Janet Anderson / Marshall Space Flight Center / Megan Watzke.

Greetings, Orbiter.ch

jeudi 17 novembre 2011

NASA Orbiter Catches Mars Sand Dunes In Motion












NASA - Mars Reconnaissance Orbiter (MRO) patch.

Nov. 17, 2011

Images from NASA's Mars Reconnaissance Orbiter (MRO) show sand dunes and ripples moving across the surface of Mars at dozens of locations and shifting up to several yards. These observations reveal the planet's sandy surface is more dynamic than previously thought.


A dune in the northern polar region of Mars shows significant changes between two images taken on June 25, 2008 and May 21, 2010 by NASA's Mars Reconnaissance Orbiter. Image credit: NASA / JPL-Caltech / Univ. of Ariz. / JHUAPL.

"Mars either has more gusts of wind than we knew about before, or the winds are capable of transporting more sand," said Nathan Bridges, planetary scientist at the Johns Hopkins University's Applied Physics Laboratory in Laurel, Md., and lead author of a paper on the finding published online in the journal Geology. "We used to think of the sand on Mars as relatively immobile, so these new observations are changing our whole perspective."

While red dust is known to swirl all around Mars in storms and dust devils, the planet's dark sand grains are larger and harder to move. Less than a decade ago, scientists thought the dunes and ripples on Mars either did not budge or moved too slowly for detection.


A rippled dune front in Herschel Crater on Mars moved an average of about two meters (about two yards) between March 3, 2007 and December 1, 2010. Image credit: NASA / JPL-Caltech / Univ. of Ariz. / JHUAPL.

MRO was launched in 2005. Initial images from the spacecraft's High Resolution Imaging Science Experiment (HiRISE) camera documented only a few cases of shifting sand dunes and ripples, collectively called bedforms. Now, after years of monitoring the martian surface, the spacecraft has documented movements of a few yards or meters per year in dozens of locations across the planet.

The air on Mars is thin, so stronger gusts of wind are needed to push a grain of sand. Wind-tunnel experiments have shown that a patch of sand would take winds of about 80 mph to move on Mars compared with only 10 mph on Earth. Measurements from the meteorology experiments on NASA's Viking landers in the 1970s and early 1980s, in addition to climate models, showed such winds should be rare on Mars.


A rippled patch of sand in Becquerel Crater on Mars moved about two meters (about two yards) between November 24, 2006 and September 5, 2010. Image credit: NASA / JPL-Caltech / Univ. of Ariz. / JHUAPL.

The first hints that Martian dunes move came from NASA's Mars Global Surveyor, which operated from 1997 to 2006. But the spacecraft's cameras lacked the resolution to definitively detect the changes. NASA's Mars Exploration Rovers also detected hints of shifting sand when they touched down on the red planet's surface in 2004. The mission team was surprised to see grains of sand dotting the rovers' solar panels. They also witnessed the rovers' track marks filling in with sand.

"Sand moves by hopping from place to place," said Matthew Golombek, a co-author of the new paper and a member of the Mars Exploration Rover and MRO teams at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Before the rovers landed on Mars, we had no clear evidence of sand moving."


A rippled dune front in Herschel Crater on Mars moved an average of about one meter (about one yard) between March 3, 2007 and December 1, 2010. Image credit: NASA / JPL-Caltech / Univ. of Ariz. / JHUAPL.

Not all of the sand on Mars is blowing in the wind. The study also identifies several areas where the bedforms did not move.

"The sand dunes where we didn't see movement today could have larger grains, or perhaps their surface layers are cemented together," said Bridges, who also is a member of the HiRISE team. "These studies show the benefit of long-term monitoring at high resolution."


The eastern margin of a rippled dune in Herschel Crater on Mars moved an average distance of three meters (about three yards) between March 3, 2007 and December 1, 2010. Image credit: NASA / JPL-Caltech / Univ. of Ariz. / JHUAPL.

According to scientists, the seemingly stationary areas might move on much larger time scales, triggered by climate cycles on Mars that last tens of thousands of years. The tilt of Mars' axis relative to its orbital plane can vary dramatically. This, combined with the oval shape of Mars' orbit, can cause extreme changes in the Martian climate, much greater than those experienced on Earth. Mars may once have been warm enough that the carbon dioxide now frozen in the polar ice caps could have been free to form a thicker atmosphere, leading to stronger winds capable of transporting sand.

HiRISE is operated by the University of Arizona in Tucson. The instrument was built by Ball Aerospace & Technologies Corp. of Boulder, Colo. The Mars Exploration Rovers Opportunity and Spirit were built by JPL. JPL also manages the MRO and Mars Exploration Rover projects for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver is NASA's industry partner for the MRO Project and built the spacecraft.

MRO images and additional information is available online at: http://www.nasa.gov/mission_pages/MRO

For more information about NASA Mars missions, visit the Web at: http://www.nasa.gov/mars

Animations (mentioned), Text Credit: NASA / Dwayne Brown / JPL-Caltech / Priscilla Vega.

Best regards, Orbiter.ch

The LHC's 2011 lead-ion run gets under way












CERN - European Organization for Nuclear Research logo.

17 Nov 2011

 A lead-ion collision recorded by the ALICE experiment during the 2011 run

After several months of proton collisions, the LHC is embarking on a period of lead ion running, which will last until 7 December. This should provide large quantities of data, as the LHC's performance has been dramatically improved since the first lead-ion run in 2010.

Lead ion collisions will be studied in detail by the ALICE experiment, which is optimised for lead ions, as well as by the ATLAS and CMS experiments. By studying these collisions, physicists probe matter as it would have been in the first instants of the Universe's existence. One of their main objectives is to make tiny quantities of such matter, known as Quark Gluon Plasma, and to study how it evolved into the matter that makes up the Universe today.

Note:

The European Organization for Nuclear Research (French: Organisation européenne pour la recherche nucléaire), known as CERN, is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border. Established in 1954, the organization has twenty European member states.

The term CERN is also used to refer to the laboratory itself, which employs just under 2400 full-time employees / workers, as well as some 7931 scientists and engineers representing 608 universities and research facilities and 113 nationalities.

More information:

    CERN Bulletin: Leading lead through the LHC: http://cdsweb.cern.ch/journal/CERNBulletin/2011/43/News%20Articles/1392094?ln=en

    ALICE public website: http://aliceinfo.cern.ch/public

Follow CERN on Twitter: http://twitter.com/cern/

Image, Text, Credit: European Organization for Nuclear Research (CERN).

Cheers, Orbiter.ch

A New Map of the Moon












NASA - Lunar Reconnaissance Orbiter (LRO) patch.

Nov. 17, 2011


NASA’s Lunar Reconnaissance Orbiter science team released the highest resolution near-global topographic map of the moon ever created. This new topographic map shows the surface shape and features over nearly the entire moon with a pixel scale close to 328 feet.

Although the moon is Earth's closest neighbor, knowledge of its morphology is still limited. Due to the limitations of previous missions, a global map of the moon’s topography at high resolution has not existed until now. With LRO's Wide Angle Camera and the Lunar Orbiter Laser Altimeter instrument, scientists can now accurately portray the shape of the entire moon at high resolution.

For more information about LRO, visit: http://www.nasa.gov/mission_pages/LRO/main/index.html and http://lunar.gsfc.nasa.gov/

Image, Text, Credit: NASA / Goddard Space Flight Center / DLR / ASU.

Greetings, Orbiter.ch

mercredi 16 novembre 2011

New LHC results announced in Paris












CERN - European Organization for Nuclear Research logo.

16 Nov 2011

This week's Hadron Collider Physics Symposium (HCP2011) in Paris is the first opportunity for the LHC experiments, ATLAS, CMS and LHCb to present new results following the end of the LHC's 2011 proton run. For the fourth large LHC collaboration, ALICE, 2011 is just getting underway with the LHC embarking on a four-week lead-ion run.

Hadron Collider Physics Symposium (HCP2011)

Highlights presented at HCP2011 include the first Higgs search result that combines data from ATLAS and CMS. This analysis includes data collected up to August, and it underlines the conclusions that were presented that month: the Standard Model Higgs boson is running out of places to hide. If it exists, it will either be found or definitively ruled out during the course of next year's LHC run. Finding this long sought particle would be a triumph for the LHC, ruling it out would herald major change in the way we view our universe at the microscopic level.

Large Hadron Collider (LHC)

Another highlight comes from LHCb, which has compared the decays of charm particles with those of their antimatter counterparts. LHCb can measure these decays to greater precision than any previous experiment.

Note:

The European Organization for Nuclear Research (French: Organisation européenne pour la recherche nucléaire), known as CERN, is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border. Established in 1954, the organization has twenty European member states.

The term CERN is also used to refer to the laboratory itself, which employs just under 2400 full-time employees/workers, as well as some 7931 scientists and engineers representing 608 universities and research facilities and 113 nationalities.

More information:

    Bulletin: Charming surprise: http://cdsweb.cern.ch/journal/CERNBulletin/2011/46/News%20Articles/1398216?ln=de

    LHCb public web page: http://lhcb-public.web.cern.ch/lhcb-public/

    Hadron Collider Physics Symposium: http://hcp2011.lpnhe.in2p3.fr/

Images, Text, Credit: CERN / HCP2011.

Greetings, Orbiter.ch

NASA Probe Data Show Evidence of Liquid Water on Icy Europa










NASA - Galileo Mission patch.

11.16.11

Data from a NASA planetary mission have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa.

The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings are published in the scientific journal Nature.


Image above: Europa's "Great Lake." Scientists speculate many more exist throughout the shallow regions of the moon's icy shell. Image Credit: Britney Schmidt / Dead Pixel FX / Univ. of Texas at Austin.

"The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program at agency headquarters in Washington. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results."

NASA's Galileo spacecraft, launched by the space shuttle Atlantis in 1989 to Jupiter, produced numerous discoveries and provided scientists decades of data to analyze. Galileo studied Jupiter, which is the most massive planet in the solar system, and some of its many moons.

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One of the most significant discoveries was the inference of a global salt water ocean below the surface of Europa. This ocean is deep enough to cover the whole surface of Europa and contains more liquid water than all of Earth's oceans combined. However, being far from the sun, the ocean surface is completely frozen. Most scientists think this ice crust is tens of miles thick.

"One opinion in the scientific community has been if the ice shell is thick, that's bad for biology. That might mean the surface isn't communicating with the underlying ocean," said Britney Schmidt, lead author of the paper and postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin. "Now, we see evidence that it's a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable."


Image above: Thera Macula (false color) is a region of likely active chaos production above a large liquid water lake in the icy shell of Europa. Color indicates topographic heights relative to background terrain. Purples and reds indicate the highest terrain. Image Credit: Paul Schenk / NASA.

Schmidt and her team focused on Galileo images of two roughly circular, bumpy features on Europa's surface called chaos terrains. Based on similar processes seen on Earth -- on ice shelves and under glaciers overlaying volcanoes -- they developed a four-step model to explain how the features form. The model resolves several conflicting observations. Some seemed to suggest the ice shell is thick. Others suggest it is thin.

This recent analysis shows the chaos features on Europa's surface may be formed by mechanisms that involve significant exchange between the icy shell and the underlying lake. This provides a mechanism or model for transferring nutrients and energy between the surface and the vast global ocean already inferred to exist below the thick ice shell. This is thought to increase the potential for life there.


Image above: Europa, as viewed from NASA’s Galileo spacecraft. Visible are plains of bright ice, cracks that run to the horizon, and dark patches that likely contain both ice and dirt. Image Credit: NASA.

The study authors have good reason to believe their model is correct, based on observations of Europa from Galileo and of Earth. Still, because the inferred lakes are several miles below the surface, the only true confirmation of their presence would come from a future spacecraft mission designed to probe the ice shell. Such a mission was rated as the second highest priority flagship mission by the National Research Council's recent Planetary Science Decadal Survey and is being studied by NASA.

Four step process for building "chaos terrains" on Europa

"This new understanding of processes on Europa would not have been possible without the foundation of the last 20 years of observations over Earth's ice sheets and floating ice shelves," said Don Blankenship, a co-author and senior research scientist at the Institute for Geophysics, where he leads airborne radar studies of the planet's ice sheets.

Galileo was the first spacecraft to directly measure Jupiter's atmosphere with a probe and conduct long-term observations of the Jovian system. The probe was the first to fly by an asteroid and discover the moon of an asteroid. NASA extended the mission three times to take advantage of Galileo's unique science capabilities, and it was put on a collision course into Jupiter's atmosphere in September 2003 to eliminate any chance of impacting Europa.

The Galileo mission was managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for the agency's Science Mission Directorate.

For images and a video animation of the findings, visit the University of Texas at Austin: http://www.jsg.utexas.edu/news/2011/11/scientists-find-evidence-for-great-lake-on-europa/

Images (mentioned), Video, Text, Credits: NASA / Dwayne Brown / Marc Airhart, University of Texas at Austin.

Greetings, Orbiter.ch

The Cool Clouds of Carina












ESO - European Southern Observatory logo.

16 November 2011

APEX gives us a new view of star formation in the Carina Nebula

The Cool Clouds of Carina

Observations made with the APEX telescope in submillimetre-wavelength light reveal the cold dusty clouds from which stars form in the Carina Nebula. This site of violent star formation, which plays host to some of the highest-mass stars in our galaxy, is an ideal arena in which to study the interactions between these young stars and their parent molecular clouds.

Using the LABOCA camera on the Atacama Pathfinder Experiment (APEX) telescope on the plateau of Chajnantor in the Chilean Andes, a team of astronomers led by Thomas Preibisch (Universitäts–Sternwarte München, Ludwig-Maximilians-Universität, Germany), in close cooperation with Karl Menten and Frederic Schuller (Max-Planck-Institut für Radioastronomie, Bonn, Germany), imaged the region in submillimetre light. At this wavelength, most of the light seen is the weak heat glow from cosmic dust grains. The image therefore reveals the clouds of dust and molecular gas — mostly hydrogen — from which stars may form. At -250ºC, the dust grains are very cold, and the faint glow emanating from them can only be seen at submillimetre wavelengths, significantly longer than those of visible light. Submillimetre light is, therefore, key to studying how stars form and how they interact with their parent clouds.

The Carina Nebula in the constellation of Carina

The APEX LABOCA observations are shown here in orange tones, combined with a visible light image from the Curtis Schmidt telescope at the Cerro Tololo Interamerican Observatory. The result is a dramatic, wide-field picture that provides a spectacular view of Carina’s star formation sites. The nebula contains stars with a total mass equivalent to over 25 000 Suns, while the mass of the gas and dust clouds is that of about 140 000 Suns.

However, only a fraction of the gas in the Carina Nebula is in sufficiently dense clouds to collapse and form new stars in the immediate future (in astronomical terms, meaning within the next million years). In the longer term, the dramatic effects of the massive stars already in the region on their surrounding clouds may accelerate the star formation rate.

High-mass stars live for only a few million years at most (a very short lifespan compared to the ten billion years of the Sun), but they profoundly influence their environments throughout their lives. As youngsters, these stars emit strong winds and radiation that shape the clouds around them, perhaps compressing them enough to form new stars. At the ends of their lives, they are highly unstable, being prone to outbursts of stellar material until their deaths in violent supernova explosions.

Digitized Sky Survey Image of Eta Carinae Nebula

A prime example of these violent stars is Eta Carinae, the bright yellowish star just to the upper left of the centre of the image. It has over 100 times the mass of our Sun, and is among the most luminous stars known. Within the next million years or so, Eta Carinae will explode as a supernova, followed by yet more supernovae from other massive stars in the region.

These violent explosions rip through the molecular gas clouds in their immediate surroundings, but after the shockwaves have travelled more than about ten light-years they are weaker, and may instead compress clouds that are a little further away, triggering the formation of new generations of stars. The supernovae may also produce short-lived radioactive atoms that are picked up by the collapsing clouds. There is strong evidence that similar radioactive atoms were incorporated into the cloud that collapsed to form our Sun and planets, so the Carina Nebula may provide additional insights into the creation of our own Solar System.

video
The Cool Clouds of Carina

The Carina Nebula is some 7500 light-years distant in the constellation of the same name (Carina, or The Keel). It is among the brightest nebulae in the sky because of its large population of high-mass stars. At about 150 light-years across, it is several times larger than the well-known Orion Nebula. Even though it is several times further away than the Orion Nebula, its apparent size on the sky is therefore about the same, making it also one of the largest nebulae in the sky.

The 12-metre-diameter APEX telescope is a pathfinder for ALMA, the Atacama Large Millimeter/submillimeter Array, a revolutionary new telescope that ESO, together with its international partners, is building and operating, also on the Chajnantor plateau. APEX is itself based on a single prototype antenna constructed for the ALMA project, while ALMA will be an array of 54 antennas with 12-metre diameters, and an additional 12 antennas with 7-metre diameters. While ALMA will have far higher angular resolution than APEX, its field of view will be much smaller. The two telescopes are complementary: for example, APEX will find many targets across wide areas of sky, which ALMA will be able to study in great detail.

APEX is a collaboration between the Max-Planck-Institute for Radio Astronomy (MPIfR), the Onsala Space Observatory (OSO) and ESO. The operation of APEX is entrusted to ESO.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

More information:

These LABOCA observations are described in the paper “A deep wide-field sub-mm survey of the Carina Nebula complex” by Preibisch et al., A&A, 525, A92 (2011): http://adsabs.harvard.edu/abs/2011A%26A...525A..92P

ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive astronomical observatory. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 40-metre-class European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Link:

More information about the work of Thomas Preibisch’s team on the Carina Nebula: A panchromatic  view of massive star feedback and triggered star formation in the Carina Nebula: http://www.usm.lmu.de/people/preibisch/carina_project.html

Images, Text, Credits: ESO / APEX / T. Preibisch et al. (Submillimetre); N. Smith, University of Minnesota / NOAO / AURA / NSF (Optical) / IAU and Sky & Telescope / Digitized Sky Survey 2. Acknowledgment: Davide De Martin / Video: ESO / APEX / T. Preibisch et al.; N. Smith, University of Minnesota / NOAO / AURA / NSF; Nick Risinger (skysurvey.org); Digitized Sky Survey 2. Music: John Dyson (from the album Moonwind) / Douglas Pierce-Price (ALMA / APEX).

Cheers, Orbiter.ch

Cosmic particle accelerators get things going












ESA - Cluster II Mission patch.

16 November 2011

ESA's Cluster satellites have discovered that cosmic particle accelerators are more efficient than previously thought. The discovery has revealed the initial stages of acceleration for the first time, a process that could apply across the Universe.

All particle accelerators need some way to begin the acceleration process. For example, the Large Hadron Collider at CERN employs a series of small accelerators to get its particles up to speed before injecting them into the main 27 km-circumference ring for further acceleration.

In space, large magnetic fields guide particles known as cosmic rays across the Universe at almost the speed of light, but are notoriously bad at getting them moving in the first place.

Astrophysical shocks are a diverse collection

In space, large magnetic fields guide particles known as cosmic rays across the Universe at almost the speed of light, but are notoriously bad at getting them moving in the first place.

Now ESA's Cluster mission has shown that something similar to the 'staging' process used at CERN is happening above our heads in the natural particle accelerators of space.

On 9 January 2005, Cluster's four satellites passed through a magnetic shock high above Earth. The spinning craft were aligned almost perfectly with the magnetic field, allowing them to sample what was happening to electrons on very short timescales of 250 milliseconds or less.

The measurements showed that the electrons rose sharply in temperature, which established conditions favourable to larger scale acceleration.

It had long been suspected that shocks could do this, but the size of the shock layers and the details of the process had proved difficult to pin down. Not any more. 

Steven J. Schwartz, Imperial College London, and colleagues used the Cluster data to estimate the thickness of the shock layer. This is important because the thinner a shock is, the more easily it can accelerate particles.

Cluster spacecraft encounter Earth's bow shock

"With these observations, we found that the shock layer is about as thin as it can possibly be," says Dr Schwartz.

Thin in this case corresponds to about 17 km. Previous estimates had only been able to tie down the width of the shock layers above Earth at no more than 100 km.

This is the first time anyone has seen such details of the initial acceleration region.

The knowledge is important because shocks are everywhere in the Universe. They are created wherever a fast-flowing medium hits an obstacle or another flow.

For example, a supersonic aeroplane collides continuously with the atmosphere before the air has a chance to get out of the way, piling it up into a shock in front of the aircraft that we hear as a sonic boom.

In the Solar System, the Sun gives out a fast-moving, electrically charged wind. As it encounters the magnetic field of Earth, a permanent shock wave is created in front of our planet.

Cluster II spacecrafts

Cluster has been instrumental in studying this phenomenon and the new results in this local environment may be applicable on large scales. Shocks are also found around exploding stars, young stars, black holes and whole galaxies. Space scientists suspect that these may be the origin of the high-energy cosmic rays that fill the Universe.

Cluster has shown that very narrow shocks may be vital to kick-starting the acceleration process in those locations. It may not be the only way of starting things off, but it is definitely one way of doing it.

"This new result reveals the size of the proverbial 'black box', constraining the possible mechanisms within it involved in accelerating particles," says Matt Taylor, ESA Cluster project scientist.

"Yet again, Cluster has provided us with a clear insight into a physical process that occurs throughout the Universe."

Related links:

Cluster reveals Earth's bow shock is remarkably thin: http://sci.esa.int/jump.cfm?oid=49637

Exploring the Sun-Earth connection: http://www.esa.int/SPECIALS/Cluster/

Space Operations & Situational Awareness: http://www.esa.int/SPECIALS/Operations/index.html

Cluster overview: http://www.esa.int/esaSC/120383_index_0_m.html

Cluster II operations: http://www.esa.int/SPECIALS/Operations/SEMYSMQJNVE_0.html

Images, Text, Credits: NASA / ESA and The Hubble Heritage Team STScI / AURA (LL Ori); ESA & Garrelt Mellema, Leiden University, the Netherlands (Red Spider Nebula); CEA / DSM / DAPNIA / SAp and ESA / XMM-Newton (SN 1006); ESA & Lotfi Ben Jaffel, Institut d'Astrophysique de Paris-CNRS-INSU, Martin Kornmesser & Lars Lindberg Christensen (Solar System); ESA / AOES Medialab (Earth's bow shock); ESO (NGC 6744); NRAO / AUI (Cygnus A); NASA / CXC / CfA / M.Markevitch et al. (Bullet Cluster) / EADS Astrium.

Greetings, Orbiter.ch

Soyuz TMA-22 Docking to the International Space Station











ROSCOSMOS - Soyuz TMA-22 Mission patch.

11/16/2011

At 11:36 Moscow time were open passageways between transport manned spacecraft "Soyuz TMA-22" and a small research module "Search" (MIM-2) of the International Space Station.

Arrival of the Soyuz TMA-22 spacecraft to ISS

The crew commander of the 29th long-term expedition Michael Fossum (NASA), the flight engineers Sergei Volkov (Roscosmos) and Satoshi Furukawa (JAXA) was warmly welcomed by the crew arrived at the ISS Expedition 29/30 long, consisting of a flight engineer of ISS-30 MKS-29/ Commandant Daniel Burbank (NASA), ISS-30 Shkaplerova Anton and Anatoly Ivanishin (Roscosmos).

video
Soyuz TMA-22 Docking to the International Space Station

The first set foot on the ISS Astronaut Space Agency Shkaplerov Anton, went after him at the station astronaut (NASA), Daniel Burbank and Russian cosmonaut Anatoly Ivanishin, after which the crew of six people spoke to the head of the Federal Space Agency, VA Popovkin.

Head of Russian Federal Space Agency congratulated the newly arrived cosmonauts and astronauts to the completion of free flight and the arrival of the ISS. He noted that "we do not doubt the work of staff."

International Space Station (ISS)

"The first week will have you hard enough, - said Victor A. Popovkin - so I ask the old crew to provide any assistance and support to newly arrived colleagues at the reception station and works."

Referring to Michael Fossum, Sergei Volkov and Satoshi Furukawa, head of Russian Federal Space Agency, VA Popovkin wished them a successful mission and the warm meeting on the ground.

Original article in Russian: http://www.federalspace.ru/main.php?id=2&nid=18272

More videos about Soyuz TMA-22 docking (Soyuz hatch opening), visit: http://tvroscosmos.ru/frm/kosmostv/vesti/2011/vesti161111.php

Images, Video, Text, Credits: Roscosmos PAO / NASA / NASA TV / Translation: Orbiter.ch.

Best regards, Orbiter.ch

mardi 15 novembre 2011

NASA Extends MESSENGER Mission












NASA - MESSENGER Mission to Mercury patch.

Nov. 15, 2011

NASA has announced that it will extend the MESSENGER mission for an additional year of orbital operations at Mercury beyond the planned end of the primary mission on March 17, 2012. The MESSENGER probe became the first spacecraft to orbit the innermost planet on March 18, 2011.

"We are still ironing out the funding details, but we are pleased to be able to support the continued exploration of Mercury," said NASA MESSENGER Program Scientist Ed Grayzeck, who made the announcement on November 9 at the 24th meeting of the MESSENGER Science Team in Annapolis, Md.

The spacecraft's unprecedented orbital science campaign is providing the first global close-up of Mercury and has revolutionized scientific perceptions of that planet. The extended mission will allow scientists to learn even more about the planet closest to the Sun, says MESSENGER Principal investigator Sean Solomon, of the Carnegie Institution of Washington.

"During the extended mission we will spend more time close to the planet than during the primary mission, we'll have a broader range of scientific objectives, and we'll be able to make many more targeted observations with our imaging system and other instruments," says Solomon. "MESSENGER will also be able to view the innermost planet as solar activity continues to increase toward the next maximum in the solar cycle. Mercury's responses to the changes in its environment over that period promise to yield new surprises."


Image above: Hollowed Ground. One objective of the extended MESSENGER mission is to determine the morphological and compositional context of "hollows" and their relationship to bright crater-floor deposits and pyroclastic vents. The crater at the center of this image is home to more of the "hollows" that dot Mercury's surface, which appear here as high-reflectance features near the crater's central peak and around its floor-wall boundary. Date acquired: October 21, 2011.

The extended mission has been designed to answer six scientific questions, each of which has arisen only recently as a result of discoveries made from orbit:

    What are the sources of surface volatiles on Mercury?
    How late into Mercury's history did volcanism persist?
    How did Mercury's long-wavelength topography change with time?
    What is the origin of localized regions of enhanced exospheric density at Mercury?
    How does the solar cycle affect Mercury's exosphere and volatile transport?
    What is the origin of Mercury's energetic electrons?

MESSENGER spacecraft

"Advancements in science have at their core the evaluation of hypotheses in the light of new knowledge, sometimes resulting in slight changes in course, and other times resulting in paradigm shifts, opening up entirely new vistas of thought and perception," says MESSENGER Project Scientist Ralph McNutt, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "With the early orbital observations at Mercury we are already seeing the beginnings of such advancements. The extended mission guarantees that the best is indeed ‘yet to be' on the MESSENGER mission, as this old-world Mercury, seen in a very new light, continues to give up its secrets."

For more information about the MESSENGER mission, visit: http://www.nasa.gov/mission_pages/messenger/main/index.html and http://messenger.jhuapl.edu/

Images, Text, Credits: NASA / Johns Hopkins University Applied Physics Laboratory / Carnegie Institution of Washington.

Cheers, Orbiter.ch

lundi 14 novembre 2011

On Estimating Global Monthly Carbon Dioxide Fluxes by Region










JAXA - IBUKI (GOSAT) Mission patch.

Nov. 14. 2011

On Estimating Global Monthly Carbon Dioxide Fluxes by Region, utilizing the observational data obtained by the Greenhouse gases Observing Satellite "IBUKI" (GOSAT)

1. Summary of the achievement

(1) Improved precision of CO2 source/sink (flux) estimates
Monthly CO2 sources and sinks (net fluxes) in 64 subcontinental-scale regions over a 12 month period from June 2009 to May 2010 were estimated using both CO2 concentrations retrieved from the soundings of the Greenhouse gases Observing Satellite "IBUKI" (GOSAT) and the published ground-based CO2 values (Note 1). It has been confirmed that uncertainties in CO2 flux estimates can be reduced significantly (as much as by about 50%) with the addition of the GOSAT data to the ground-based monitoring data (refer to the attached document for more detail). This constitutes the first concrete demonstration of the utility of satellite data in estimating global CO2 fluxes. This result was published as a scientific paper in the Scientific Online Letters on the Atmosphere (SOLA) issued by the Meteorological Society of Japan on October 29, 2011.

(2) Contribution of the CO2 flux estimation with GOSAT data

I) With the addition of the GOSAT observational data to the ground-based monitoring data, significant uncertainty reduction was achieved in the monthly regional CO2 flux estimates. It is expected that continuous CO2 monitoring by GOSAT and further refinement of the data processing methods will lead to effective monitoring of variations in monthly regional CO2 fluxes.

II) In particular, uncertainties of CO2 fluxes estimated for South America, Africa, the Near and Middle East, and Asia have been reduced by as much as about 50% (annual average) with the addition of the GOSAT data to the ground-based monitoring data.

III) The seasonal trends of summertime CO2 uptake associated with plant photosynthesis and wintertime CO2 emission in high latitudinal regions of the northern hemisphere are broadly consistent with past findings. It is expected that the response of terrestrial biosphere to future climate change, in terms of changes in flux amounts, may be detected in its early stage with continuing observation by GOSAT and further refinements in the data processing methods.

IV) The global annual flux for the period of June 2009 to May 2010 was evaluated at around 4 gigatons of carbon per year, which is almost equivalent to the values calculated from the growth rates of CO2 concentrations in the atmosphere for this period. The validity of this annual flux and the contributions of anthropogenic emissions or fluxes of natural origin will be the subject of further investigations.

V) Monthly fluxes calculated from the GOSAT data and the ground-based monitoring data in some regions show differences to those calculated from only the ground-based monitoring data. It is expected that continuous monitoring by GOSAT and further research undertakings will yield further understanding of the CO2 flux behavior.

IBUKI (GOSAT) satellite

2. Next steps

(1) Evaluation and verification of the results of CO2 flux estimation by overseas research institutes and researchers in the carbon cycle research field.
The 64-regional monthly flux estimates will be disseminated to affiliated researchers selected by means of GOSAT Research Announcements for Principal Investigators, in order for these estimates to be evaluated and verified. In addition we will evaluate the accuracy and consistency of the results by means of comparisons with independent flux estimation results from overseas research groups. At the same time, suggestions from researchers worldwide engaged in this field will be collected by means of international workshops and meetings. On the basis of these results, we intend to make improvements as they prove necessary, and thereafter the monthly regional CO2 fluxes will be recalculated (Note 3). With this improved CO2 flux data product, the product of the three-dimensional distributions of CO2 concentration (Note 4) will be prepared and released to the general public.

(2) Ongoing development of the GOSAT follow-on
With this first demonstration of the utility of the GOSAT data, we seek to expand the contribution of GOSAT to carbon cycle research, global environmental monitoring, and climate change policy making. The MOE, NIES and JAXA have begun investigations aimed at the development of a GOSAT follow-on - one with enhanced capacities for efficient measurements. A launch date has been set for around 2016 at the earliest.
The GOSAT follow-on would carry an advanced Fourier Transform Spectrometer in order to increase the number of measurements. Furthermore, improvements will be made in the data processing algorithms and flux estimation models in order to obtain more precise flux estimates.
With the planned launch of a satellite Orbital Carbon Observatory 2 (OCO-2) by the United States in the near future, we intend to continue to collaborate and cooperate internationally with these communities on the measurement of greenhouse gases from space.

(Note 1)
Published global CO2 data from NOAA/ESRL/GMD as GLOBALVIEW-CO2 2011.
(Ref. http://www.esrl.noaa.gov/gmd/ccgg/globalview/co2/co2_intro.html)
Expressed as "GV data" in the attached document.

(Note 2)
Online journal of Scientific Online Letters on the Atmosphere (SOLA) issued by the Meteorological Society of Japan.
Title of the paper: On the benefit of GOSAT observations to the estimation of regional CO2 fluxes
Authors: H. Takagi, T. Saeki, T. Oda, M. Saito, V. Valsala, D. Belikov, R. Saito,
Y. Yoshida, I. Morino, O. Uchino, R. J. Andres, T. Yokota, and S. Maksyutov
Bibliography: SOLA, 2011, Vol. 7, 161-164, doi:10.2151/sola.2011-041

(Note 3)
This will be released as the Level 4A product of the GOSAT standard data products.

(Note 4)
This will be released as the Level 4B product, 3D distribution of CO2 concentration at intervals of 6 hours in every 2.5 degree mesh, of the GOSAT standard data products.

On the estimation of regional CO2 fluxes from GOSAT observations

The GOSAT Project, a joint undertaking of the Ministry of the Environment Japan, the National Institute for Environmental Studies, and the Japan Aerospace Exploration Agency, has been providing the general public with the global distribution of CO2 concentrations (column-averaged dry air mole fractions of CO2, or XCO2) retrieved from GOSAT data obtained over clear-sky regions.

Researchers of the Project estimated regional CO2 fluxes from data collected in the networks of surface CO2 measurement sites and the GOSAT XCO2 retrievals via inverse modeling. Until recently, regional CO2 fluxes have been inferred from the ground-based network data (about 200 sites around the globe). Since many of the measurement sites are located over the developed nations, the uncertainty of fluxes estimated for regions away from the observation networks was sizable. This time, the researchers evaluated the degree to which the GOSAT XCO2 retrievals contribute to reducing the uncertainty of the regional fluxes. Their findings appeared in the Scientific Online Letters on the Atmosphere, a publication by the Meteorological Society of Japan, on October 29, 2011 (available at http://www.jstage.jst.go.jp/article/sola/7/0/161/_pdf). The results are outlined below.

1. Method

The CO2 fluxes were estimated for 64 subcontinental-scale regions on a monthly basis over a one-year period between June 2009 and May 2010 from

1. ground-based network data (GLOBALVIEW-CO21; hereafter denoted as GV)
2. both the GV data and GOSAT XCO2 retrievals.
The GV data available at the timing of submitting the research letter manuscript contained data until December 2009. The estimation was therefore performed using GV data extrapolated to the year 2010. The results shown below are based on a newly updated GV data that covers the entire analysis period. The GOSAT XCO2 retrievals, which were found to be negatively biased, were corrected based on the result of GOSAT data validation activities2. Prior to the use in inverse modeling, these corrected XCO2 values were gridded to 5° x 5° cells and averaged on a monthly basis. The GV data were also monthly-averaged.
In the analysis, the rate of uncertainty reduction (UR) in percent attained via adding GOSAT XCO2 retrievals to GV data was calculated as,


where σGV and σGV+GOSAT denote the uncertainty of a monthly flux estimated from GV data only and from both GV dataset and GOSAT XCO2 retrievals, respectively.

2. Results

Figure 1 shows annual means of the regional uncertainty reduction rates. Pronounced reductions, as much as about 50%, were found in the uncertainty of fluxes estimated for regions in South America, Africa, Middle East, and Asia, where the sparsity of the ground-based measurement sites is most evident.


Figure 1. The rate of reduction in the uncertainty of monthly surface CO2 flux estimates, attained via the addition of GOSAT XCO2 retrievals to the dataset of GLOBALVIEW surface observations. The values shown are annual means over the June 2009-May 2010 analysis period.

Shown in Figure 2 is the time series of the monthly uncertainty reduction rate and fluxes estimated from GV data and from both GV data and GOSAT XCO2 retrievals. Two regions, south-western tropical Africa (marked as A in Fig. 1; top panel in Fig. 2) and north-western temperate North America (B in Fig. 1; bottom panel in Fig. 2), are contrasted here. South-western tropical Africa and north-western temperate North America represent regions where ground-based measurement sites are sparse and dense, respectively. The lines in the figure show fluxes estimated from GV data (red) and from both GV data and GOSAT XCO2 retrievals (blue). The vertical bars (gray) indicate the monthly uncertainty reduction rate. The uncertainty associated with the estimated fluxes is shown with error bars. The green line and the shade behind indicate the value of a priori flux and its uncertainty used in inverse modeling. The GV-based monthly fluxes estimated for south-western tropical Africa (red) are associated with large uncertainty since the estimation of the fluxes is based on measurements taken distant from the region. By introducing GOSAT XCO2 retrievals to GV data, the uncertainty of the fluxes was reduced significantly (blue error bar). In contrast, a relatively large number of ground-based measurement sites are located within and nearby north-western temperate North America. In addition, the data obtained at these sites are higher in precision than GOSAT XCO2 retrievals. Therefore, they have larger influence in determining the region's flux. Because of this, the fluxes and their uncertainty estimated from GV data and from both GV data and GOSAT XCO2 retrievals are nearly identical over the analysis period. GOSAT XCO2 retrievals are particularly beneficial in reducing the uncertainty of fluxes estimated for regions in Africa, South America, Middle East, and Asia.


Figure 2. The time series of a priori flux (green), fluxes estimated from GV (red), a posteriori flux estimated from both GV data and GOSAT XCO2 retrievals (blue), and the uncertainty reduction rate (gray vertical bars). The green shade indicates the uncertainty of a priori flux. The error bar (red and blue) shows the uncertainty of the estimated flux. Results for south-western Tropical Africa (A; top panel) and north-western Temperate North America (B; bottom panel) are shown.

The 64-regional fluxes estimated from GV data and GOSAT XCO2 retrievals are shown in Figure 3. The results for summer (July 2009), fall (October 2009), winter (January 2010) and spring (April 2010) are presented. Seasonal trends seen in the fluxes of high latitudinal regions in the Northern Hemisphere are broadly consistent with past findings.


Figure 3. 64-regional fluxes estimated from both GV data and GOSAT XCO2 retrievals. Results for summer (July 2009), fall (October 2009), winter (January 2010) and spring (April 2010) are shown.

3. Plans

For evaluation purposes, the GV-GOSAT based flux data described above are released on October 28th to researchers in the field of carbon balance estimation and atmospheric transport modeling whose research proposals were adopted during the past GOSAT Research Announcements. It is also planned that these flux estimations are intercompared with those obtained at several other research institutes overseas for data quality check. The result of these evaluation studies will be reflected in improving the data processing algorithms. The release of the 64-regional fluxes (the Level 4A data product) and the three-dimensional CO2 distributions (the Level 4B data product) simulated with the 64-regional fluxes to the general public follows after the completion of these data evaluation and improvement processes. The temporal coverage of these data products will be extended after an annual update of GV data.
The Ministry of the Environment Japan, the National Institute for Environmental Studies, and the Japan Aerospace Exploration Agency will continue with the cooperative effort in providing the general public with the GOSAT data products. The three parties recently initiated the preparation of developing a GOSAT follow-on.

References

1. GLOBALVIEW-CO2 (2011), Cooperative Atmospheric Data Integration Project - Carbon Dioxide. CD-ROM, NOAA ESRL, Boulder, Colorado (Also available on Internet via anonymous FTP to ftp.cmdl.noaa.gov, Path: ccg/co2/GLOBALVIEW).

2. Morino, I., Uchino, O., Inoue, M., Yoshida, Y., Yokota, T., Wennberg, P. O., Toon, G. C., Wunch, D., Roehl, C. M., Notholt, J., Warneke, T., Messerschmidt, J., Griffith, D. W. T., Deutscher, N. M., Sherlock, V., Connor, B., Robinson, J., Sussmann, R., and Rettinger, M. (2011), Preliminary validation of column-averaged volume mixing ratios of carbon dioxide and methane retrieved from GOSAT short-wavelength infrared spectra, Atmos. Meas. Tech., 4, 1061-1076, doi:10.5194/amt-4-1061-2011.

Mission website:

Greenhouse gases Observing SATellite "IBUKI" (GOSAT): http://www.jaxa.jp/projects/sat/gosat/index_e.html

Images, Graphics, Text, Credits: Japan Aerospace Exploration Agency (JAXA) / National Institute for Environmental Studies (NIES) / Ministry of the Environment, Japan (MOE).

Best regards, Orbiter.ch

Launch of manned spacecraft "Soyuz TMA-22"











ROSCOSMOS - Soyuz TMA-22 Mission patch.

11/14/2011


Image above: Soyuz TMA-22 launches for the International Space Station as snow falls at the Baikonur Cosmodrome. (NASA TV).

video
Soyuz TMA-22 Launch

November 14 at 08.14.04 Moscow time from the launch site Baikonur site 1 was put space rocket (ILV) "Soyuz-FG" with transport manned spacecraft (TLC) "Soyuz TMA-22" (Commander Anton Shkaplerov (Roscosmos) ; flight engineers: A. Ivanishin (Roscosmos), Daniel Burbank (NASA).


Image above: A stuffed doll of a red bird from the mobile game "Angry Birds" hangs inside Soyuz TMA-22 as a "zero-G indicator." (NASA TV).

After 528 seconds of flight rocket TPK "Soyuz TMA-22" cleanly separated from the third stage to orbit an artificial satellite.

Docking of the WPK "Soyuz TMA-22" from the International Space Station is scheduled for November 16 at 09.33 Moscow time (05:33 GMT Wednesday, Nov. 16).

Last of its type


Image above: Soyuz TMA-22, the last of the TMA-class spacecraft, seen being readied for launch at the Baikonur Cosmodrome. (RSC Energia).

Soyuz TMA-22's launch also began the last flight of the TMA-class spacecraft. Since last year, Russia has been phasing in use of "digital" Soyuz TMA-M-class capsules, which have been upgraded to feature modern navigation and control systems.

Soyuz TMA-03M is scheduled to lift off on Dec. 21, 2011, with Expedition 30 crewmembers Oleg Kononenko, André Kuipers and Don Pettit.

The first of the TMA vehicles launched to the International Space Station nine years ago in 2002. Like the TMA-M, the TMA superseded an earlier version of the Soyuz, the TM-class, used since 1986.

Soyuz TMA-22 is the 111th Soyuz spacecraft to fly since the very first Soyuz (simply "Soyuz 1") on April 23, 1967. Almost all of the crewed Soyuz lifted off from the same pad, referred to as "Gagarin's Start," after the world's first human in space, Yuri Gagarin, who departed Earth from the same pad 50 years ago.

Original text in Russian: http://www.federalspace.ru/main.php?id=2&nid=18257

Images (mentioned), Video, Text, Credits: Press Service of the Russian Space Agency (Roscosmos PAO) / Roscosmos TV / Translation: Orbiter.ch.

Greetings, Orbiter.ch