samedi 28 février 2015

Russian military Launches Bars-M1 Satellite









Russian Ministry of Defense logo.

February 28, 2015

Soyuz-2.1a rocket carrying Bars-M1 launch

Russian northern spaceport Plesetsk Cosmodrome has sent off yet another brand new reconnaissance satellite on Thursday, February 26 at 11:01 UTC on board a Soyuz-2.1a rocket from pad 43/4. 10 minutes later the satellite was deployed into a polar orbit in which it would move to its operational orbit about 500 km high.

As is typical for classified Russian military missions, the launch was not broadcast.

video
Launch of "Soyuz-2.1a" military satellite on board

Bars-M1 will replace the older generation of film-return regional coverage spysats that has last flew 10 years ago as the Russian military and government new medium-resolution optical reconnaissance satellite tinkered for mapping use (cartography satellite), a vital function for pinpointing the locations of targets of interest.

Bars-M1 military Satellite

The spacecraft uses a new satellite bus from the Samara Space Center (builder of the Soyuz rocket and many Russian military/civilian Earth observation satellites) and optical systems from the famous LOMO.

Images, Video, Text, Credits: Russian Ministry of Defense/RT/Sen.com (image of Bars-M1 satellite)/Orbiter.ch Aerospace.

Greetings, Orbiter.ch

Died of twice Hero of the Soviet Union, Soviet cosmonaut Alexei Alexandrovich Gubarev

ROSCOSMOS logo.

28/02/2015

February 21, 2015 died twice Hero of the Soviet Union, Soviet cosmonaut Alexei Alexandrovich Gubarev.

AA Gubarev made two space flights, during which the air communication between the spacecraft and Earth astronaut sounded the call: "Zenith".

In the first flight AA Gubarev went as commander of spacecraft "Soyuz-17" with GM Grechko. Space mission on board the long-term orbital station "Salyut-4" lasted 29 days from 11 January to 9 February 1975.

In the second flight of Soviet cosmonaut again led the crew. This time, his colleague was the first Czechoslovak cosmonaut Vladimir Remek. Flight crew "Soyuz-28" and the expedition to the station "Salyut-6" held in the framework of the program "Intercosmos". Launch was held on 2 March, and landing - March 10, 1978.

Cosmonaut Alexei Alexandrovich Gubarev

Two flight AA Gubarev was twice awarded the title of Hero of the Soviet Union. After the first flight, he was awarded the title of Soviet cosmonaut.

Before flying in space AA Gubarev came from aviation. He was promoted from cadet Navy mine-torpedo Aviation School's Black Sea Fleet, combat pilot, squadron commander of Naval Aviation Regiment, the listener Air Force Academy to major general aviation.

Aleksei Gubarev almost twenty years was a member of the cosmonaut corps. In addition to successes in its main vocation - space exploration, Alexei Alexandrovich was held as a writer and scholar. In light of his book "The attraction of weightlessness" and "The orbit of life," he has published 16 scientific papers, defended his doctoral dissertation.

ROSCOSMOS Press Release: http://www.federalspace.ru/21322/

Cosmonaut Alexei Alexandrovich Gubarev biography: http://en.wikipedia.org/wiki/Aleksei_Gubarev

Press Service of the Russian Federal Space Agency/ROSCOSMOS/Translation: Orbiter.ch Aerospace.

R.I.P.; Orbiter.ch

Hubble Images a Dusty Galaxy, Home to an Exploding Star












NASA - Hubble Space Telescope patch.

February 28, 2015


The galaxy pictured here is NGC 4424, located in the constellation of Virgo. It is not visible with the naked eye but has been captured here with the NASA/ESA Hubble Space Telescope.

Although it may not be obvious from this image, NGC 4424 is in fact a spiral galaxy. In this image it is seen more or less edge on, but from above, you would be able to see the arms of the galaxy wrapping around its center to give the characteristic spiral form.

In 2012, astronomers observed a supernova in NGC 4424 — a violent explosion marking the end of a star’s life. During a supernova explosion, a single star can often outshine an entire galaxy. However, the supernova in NGC 4424, dubbed SN 2012cg, cannot be seen here as the image was taken ten years prior to the explosion. Along the central region of the galaxy, clouds of dust block the light from distant stars and create dark patches.

To the left of NGC 4424 there are two bright objects in the frame. The brightest is another, smaller galaxy known as LEDA 213994 and the object closer to NGC 4424 is an anonymous star in our Milky Way.

video
Hubble and the sunrise over Earth

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

For more information and images from Hubble Space Telescope, visit: http://www.spacetelescope.org and http://hubblesite.org

Image, Video, Text, Credits: ESA/Hubble & NASA, Acknowledgement: Gilles Chapdelaine.

Best regards, Orbiter.ch

vendredi 27 février 2015

Station Managers 'Go' For Sunday Spacewalk










ISS - Expedition 42 Mission patch.

February 27, 2015

International Space Station managers met Friday morning and gave approval to proceed with U.S. EVA 31 on Sunday, March 1 as planned. The Mission Management Team reviewed the status of spacewalk preparations as well as an analysis of the minor seepage of water into the helmet of Expedition 42 Flight Engineer Terry Virts of NASA following the last spacewalk on Feb. 25 after he was back in the crew lock section of the Quest airlock and the repressurization of the airlock had begun.

Spacewalk specialists reported that Virts’ suit — serial number 3005 — has a history of what is called “sublimator water carryover”, a small amount of residual water in the sublimator cooling component that can condense once the environment around the suit is repressurized following its exposure to vacuum during a spacewalk, resulting in a tiny amount of water pushing into the helmet.

A high degree of confidence was expressed that the suit’s systems are all in good shape and approval was given to proceed with the third spacewalk in this series of EVAs.


Image above: U.S. astronaut Barry “Butch” Wilmore checks out his spacesuit in preparation for an extravehicular activity (EVA) or spacewalk. Wilmore is the commander of Expedition 42 onboard the International Space Station. Image Credit: NASA.

During Sunday’s spacewalk, Virts and Expedition 42 Commander Barry Wilmore will deploy 400 feet of cable along the truss of the station and install antennas as part of the new Common Communications for Visiting Vehicles (C2V2) system that will provide rendezvous and navigational data to visiting vehicles approaching the station, including the new U.S. commercial crew vehicles.

It will be the 187th spacewalk in support of station assembly and maintenance, the fourth for Wilmore in his career and the third for Virts.

Swapping designations for this final scheduled spacewalk for Expedition 42, Virts will be designated extravehicular crew member 1 (EV1) on Sunday and will wear the suit with the red stripes. Wilmore will be extravehicular crew member 2 (EV2) with no stripes on his suit.

NASA Television coverage on Sunday will begin at 5 a.m. Central time. The spacewalk will begin around 6:10 a.m. Central time and is expected to last about 6 hours, 45 minutes: http://www.nasa.gov/multimedia/nasatv/index.html

For more information about International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Text, Credit: NASA.

Greetings, Orbiter.ch

jeudi 26 février 2015

Study of Atmospheric 'Froth' May Help GPS Communications











NASA logo.

February 26, 2015

--Irregularities in Earth's upper atmosphere can distort GPS signals

--Scientists are studying these irregularities to help overcome their effects on communications

When you don't know how to get to an unfamiliar place, you probably rely on a smart phone or other device with a Global Positioning System (GPS) module for guidance. You may not realize that, especially at high latitudes on our planet, signals traveling between GPS satellites and your device can get distorted in Earth's upper atmosphere.

Researchers at NASA's Jet Propulsion Laboratory, Pasadena, California, in collaboration with the University of New Brunswick in Canada, are studying irregularities in the ionosphere, a part of the atmosphere centered about 217 miles (350 kilometers) above the ground that defines the boundary between Earth and space. The ionosphere is a shell of charged particles (electrons and ions), called plasma, that is produced by solar radiation and energetic particle impact.


Image above: The Aurora Borealis viewed by the crew of Expedition 30 on board the International Space Station. The sequence of shots was taken on February 7, 2012 from 09:54:04 to 10:03:59 GMT, on a pass from the North Pacific Ocean, west of Canada, to southwestern Illinois. Image Credit: NASA/JSC.

The new study, published in the journal Geophysical Research Letters, compares turbulence in the auroral region to that at higher latitudes, and gains insights that could have implications for the mitigation of disturbances in the ionosphere. Auroras are spectacular multicolored lights in the sky that mainly occur when energetic particles driven from the magnetosphere, the protective magnetic bubble that surrounds Earth, crash into the ionosphere below it. The auroral zones are narrow oval-shaped bands over high latitudes outside the polar caps, which are regions around Earth's magnetic poles. This study focused on the atmosphere above the Northern Hemisphere. 

"We want to explore the near-Earth plasma and find out how big plasma irregularities need to be to interfere with navigation signals broadcast by GPS," said Esayas Shume. Shume is a researcher at JPL and the California Institute of Technology in Pasadena, and lead author of the study.

If you think of the ionosphere as a fluid, the irregularities comprise regions of lower density (bubbles) in the neighborhood of high-density ionization areas, creating the effect of clumps of more and less intense ionization. This "froth" can interfere with radio signals including those from GPS and aircraft, particularly at high latitudes.


Image above: CAScade, Smallsat and IOnospheric Polar Explorer (CASSIOPE) is a made-in-Canada small satellite from the Canadian Space Agency. It is comprised of three working elements that use the first multi-purpose small satellite platform from the Canadian Small Satellite Bus Program. Image Credit: Canadian Space Agency.

The size of the irregularities in the plasma gives researchers clues about their cause, which help predict when and where they will occur. More turbulence means a bigger disturbance to radio signals.

"One of the key findings is that there are different kinds of irregularities in the auroral zone compared to the polar cap," said Anthony Mannucci, supervisor of the ionospheric and atmospheric remote sensing group at JPL. "We found that the effects on radio signals will be different in these two locations."

The researchers found that abnormalities above the Arctic polar cap are of a smaller scale – about 0.62 to 5 miles (1 to 8 kilometers) – than in the auroral region, where they are 0.62 to 25 miles (1 to 40 kilometers) in diameter.

Why the difference? As Shume explains, the polar cap is connected to solar wind particles and electric fields in interplanetary space. On the other hand, the region of auroras is connected to the energetic particles in Earth's magnetosphere, in which magnetic field lines close around Earth. These are crucial details that explain the different dynamics of the two regions.

To look at irregularities in the ionosphere, researchers used data from the Canadian Space Agency satellite Cascade Smallsat and Ionospheric Polar Explorer (CASSIOPE), which launched in September 2013. The satellite covers the entire region of high latitudes, making it a useful tool for exploring the ionosphere.

GPS Communications satellite. Image Credit: NASA

The data come from one of the instruments on CASSIOPE that looks at GPS signals as they skim the ionosphere. The instrument was conceived by researchers at the University of New Brunswick.

"It's the first time this kind of imaging has been done from space," said Attila Komjathy, JPL principal investigator and co-author of the study. "No one has observed these dimensional scales of the ionosphere before."

The research has numerous applications. For instance, aircraft flying over the North Pole rely on solid communications with the ground; if they lose these signals, they may be required to change their flight paths, Mannucci said. Radio telescopes may also experience distortion from the ionosphere; understanding the effects could lead to more accurate measurements for astronomy.

"It causes a lot of economic impact when these irregularities flare up and get bigger," he said.

NASA's Deep Space Network, which tracks and communicates with spacecraft, is affected by the ionosphere. Komjathy and colleagues also work on mitigating and correcting for these distortions for the DSN. They can use GPS to measure the delay in signals caused by the ionosphere and then relay that information to spacecraft navigators who are using the DSN’s tracking data.

"By understanding the magnitude of the interference, spacecraft navigators can subtract the distortion from the ionosphere to get more accurate spacecraft locations," Mannucci said.

Other authors on the study were Richard B. Langley of the Geodetic Research Laboratory, University of New Brunswick, Fredericton, New Brunswick, Canada; and Olga Verkhoglyadova and Mark D. Butala of JPL. Funding for the research came from NASA's Science Mission Directorate in Washington. JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Space Network for NASA.

More information about NASA's Space Communications and Navigation program is at: http://www.nasa.gov/scan

Images (mentioned), Text, Credits: NASA's Jet Propulsion Laboratory/Elizabeth Landau.

Cheers, Orbiter.ch

NASA Releases First Global Rainfall and Snowfall Map from New Mission








NASA / JAXA - GPM Core Observatory patch.

February 26, 2015

Global Precipitation Measurement mission has produced its first global map of rainfall and snowfall.

Like a lead violin tuning an orchestra, the GPM Core Observatory – launched one year ago on Feb. 27, 2014, as a collaboration between NASA and the Japan Aerospace Exploration Agency – acts as the standard to unify precipitation measurements from a network of 12 satellites. The result is NASA's Integrated Multi-satellite Retrievals for GPM data product, called IMERG, which combines all of these data from 12 satellites into a single, seamless map.

The map covers more of the globe than any previous NASA precipitation data set and has repeat coverage every three hours, allowing scientists to see how rain and snow storms move around nearly the entire planet. As scientists work to understand all the elements of Earth’s climate and weather systems, and how they could change in the future, GPM provides a major step forward in providing the scientific community comprehensive and consistent measurements of precipitation.

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First Global Rainfall and Snowfall Map from New Mission

Video above: The Global Precipitation Measurement mission produced its first global map of rainfall and snowfall, from April to September 2014. The data map combines measurements from 12 satellites and the GPM Core Observatory, launched Feb 27, 2014, covers 87 percent of the globe and is updated every half hour. Image Credit: NASA's Goddard Space Flight Center.

"With the GPM core observatory acting as an anchor to allow us to cross-calibrate data from a very diverse set of satellite measurements from our international and interagency partners, we can clearly see the big picture in terms of where it’s raining or snowing across the globe," said Ramesh Kakar, GPM program scientist at NASA Headquarters in Washington.

The GPM mission includes additional satellites from NASA and JAXA, as well as satellites from the U.S. National Oceanic and Atmospheric Administration, U.S. Department of Defense's Defense Meteorological Satellite Program, European Organisation for the Exploitation of Meteorological Satellites, Indian Space Research Organisation, and France's Centre National d’Études Spatiales.

This first IMERG data set spans the initial months of GPM data collection from April to September 2014. The precipitation data collected covers the 87 percent of the globe that falls between 60 degrees north and 60 degrees south latitude, updated every half hour.

A visualization of the data from this April to September time frame offers a glimpse at what the new data set will provide to scientists.

"What this visualization shows so clearly is that all precipitation is interrelated all around the globe," said GPM Project Scientist Gail Skofronick-Jackson at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "What people sometimes don't realize is how rain over their backyard in the U.S. then goes on to affect the people in Europe once the storms go across the Atlantic."

Falling rain and snow are essential parts of Earth's water cycle, which moves water and heat energy around Earth. Near the equator where the sun's heat drives evaporation that keeps the air moist, rain systems move westward in a steady stream. At higher latitudes, which have not previously been observed in 3-D with high-resolution precipitation sensors, enormous storm fronts march eastward across North America and Europe in the Northern Hemisphere, and across the Southern Ocean that surrounds Antarctica.

For the first time with this near-global map, light rain and snow are being tracked consistently through these high latitudes and across oceans. Measuring falling snow from space has been a difficult challenge because the light icy flakes behave very differently from raindrops, said Skofronick-Jackson. Being able to study it from GPM observations now will go a long way toward improving scientists' understanding of the physics of snowfall, which in turn may improve climate and weather forecast models that don't currently represent falling snow very well.

GPM Core Observatory satellite. Image Credits: NASA/JAXA

"Being able to observe falling snow from satellites is very important for all of society and science too," Skofronick-Jackson said. "For example, snow is a vital contributor to water resources in many parts of the world, including the western United States. Snow packs that accumulate over the winter melt during the spring to supply water for drinking and agriculture."

GPM's global precipitation maps expand upon and continue the precipitation data record collected by its predecessor, the Tropical Rainfall Measuring Mission, which was launched in 1997.

Continuing this decades-long record of precipitation data is important for understanding Earth's changing climate. According to the United Nations Intergovernmental Panel on Climate Change Fifth Assessment Report, how precipitation patterns will change in the future is still largely uncertain. Rain and snowfall data collected now will contribute to climate models that provide the long-term outlook.

Data like that provided in IMERG will also inform short-term weather forecast models. Because of its global coverage, satellite data are sometimes the only precipitation data available in parts of the world that do not have ground radar, including remote locations and over the oceans. Currently in development are an IMERG data set that will be produced and made available in near-real time, four hours after observations, and an IMERG data set that is fully global.

"We get data requests from all over the world," said GPM Deputy Project Scientist George Huffman, who leads the IMERG team at Goddard. "People living in India are trying to understand the monsoon and what it means for the risk of landslides and flooding. People in Africa are working with famine relief programs that need rainfall data to forecast the growing season. Even here in the United States where we have a good weather radar network system, we need satellite data over the oceans to see what's coming."

The IMERG precipitation data as well as the entire catalogue of GPM data are freely available to registered users from Goddard's Precipitation Processing System.

Related Links:

NASA press release: "New NASA Earth Science Missions Expand View of Our Home Planet" (Feb. 26, 2015): http://www.nasa.gov/press/2015/february/new-nasa-earth-science-missions-expand-view-of-our-home-planet/

Access the precipitation data: http://pmm.nasa.gov/data-access

NASA's GPM website: http://www.nasa.gov/gpm

NASA's "Earth Right Now" website: http://www.nasa.gov/earthrightnow

Image (mentioned), Video (mentioned), Text, Credits: NASA’s Goddard Space Flight Center/Rani Gran/Ellen Gray.

Greetings, Orbiter.ch

Looking Deeply into the Universe in 3D












ESO - European Southern Observatory logo.

26 February 2015

MUSE goes beyond Hubble

MUSE goes beyond Hubble in the Hubble Deep Field South

The MUSE instrument on ESO’s Very Large Telescope has given astronomers the best ever three-dimensional view of the deep Universe. After staring at the Hubble Deep Field South region for only 27 hours, the new observations reveal the distances, motions and other properties of far more galaxies than ever before in this tiny piece of the sky. They also go beyond Hubble and reveal previously invisible objects.

MUSE stares at the Hubble Deep Field South

By taking very long exposure pictures of regions of the sky, astronomers have created many deep fields that have revealed much about the early Universe. The most famous of these was the original Hubble Deep Field, taken by the NASA/ESA Hubble Space Telescope over several days in late 1995. This spectacular and iconic picture rapidly transformed our understanding of the content of the Universe when it was young. It was followed two years later by a similar view in the southern sky — the Hubble Deep Field South.

The Hubble Deep Field South in the constellation of Tucana

But these images did not hold all the answers — to find out more about the galaxies in the deep field images, astronomers had to carefully look at each one with other instruments, a difficult and time-consuming job. But now, for the first time, the new MUSE instrument can do both jobs at once — and far more quickly.

Hubble Deep Field South — Multiple Windows on the Universe

One of the first observations using MUSE after it was commissioned on the VLT in 2014 was a long hard look at the Hubble Deep Field South (HDF-S). The results exceeded expectations.

“After just a few hours of observations at the telescope, we had a quick look at the data and found many galaxies — it was very encouraging. And when we got back to Europe we started exploring the data in more detail. It was like fishing in deep water and each new catch generated a lot of excitement and discussion of the species we were finding,”  explained Roland Bacon (Centre de Recherche Astrophysique de Lyon, France, CNRS) principal investigator of the MUSE instrument and leader of the commissioning team.

video
MUSE view of the Hubble Deep Field South

For every part of the MUSE view of HDF-S there is not just a pixel in an image, but also a spectrum revealing the intensity of the light’s different component colours at that point — about 90 000 spectra in total [1]. These can reveal the distance, composition and internal motions of hundreds of distant galaxies — as well as catching a small number of very faint stars in the Milky Way.

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MUSE view of the Hubble Deep Field South

Even though the total exposure time was much shorter than for the Hubble images, the HDF-S MUSE data revealed more than twenty very faint objects in this small patch of the sky that Hubble did not record at all [2].

“The greatest excitement came when we found very distant galaxies that were not even visible in the deepest Hubble image. After so many years of hard work on the instrument, it was a powerful experience for me to see our dreams becoming reality,” adds Roland Bacon.

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MUSE view of the Hubble Deep Field South

By looking carefully at all the spectra in the MUSE observations of the HDF-S, the team measured the distances to 189 galaxies. They ranged from some that were relatively close, right out to some that were seen when the Universe was less than one billion years old. This is more than ten times the number of measurements of distance than had existed before for this area of sky.

For the closer galaxies, MUSE can do far more and look at the different properties of different parts of the same galaxy. This reveals how the galaxy is rotating and how other properties vary from place to place. This is a powerful way of understanding how galaxies evolve through cosmic time.

video
A video view of MUSE data of the Hubble Deep Field South

“Now that we have demonstrated MUSE’s unique capabilities for exploring the deep Universe, we are going to look at other deep fields, such as the Hubble Ultra Deep field. We will be able to study thousands of galaxies and to discover new extremely faint and distant galaxies. These small infant galaxies, seen as they were more than 10 billion years in the past, gradually grew up to become galaxies like the Milky Way that we see today,” concludes Roland Bacon.

ESOcast 72 – Looking Deeply into the Universe in 3D: http://www.eso.org/public/videos/eso1507a/

Notes:
[1] Each spectrum covers a range of wavelengths from the blue part of the spectrum into the near-infrared (475‒930 nanometres).

[2] MUSE is particularly sensitive to objects that emit most of their energy at a few particular wavelengths as these show up as bright spots in the data. Galaxies in the early Universe typically have such spectra, as they contain hydrogen gas glowing under the ultraviolet radiation from hot young stars.

More information:

This research was presented in a paper entitled “The MUSE 3D view of the Hubble Deep Field South” by R. Bacon et al., to appear in the journal Astronomy & Astrophysics on 26 February 2015.

The team is composed of R. Bacon (Observatoire de Lyon, CNRS, Université Lyon, Saint Genis Laval, France [Lyon]), J. Brinchmann (Leiden Observatory, Leiden University, Leiden, The Netherlands [Leiden]), J. Richard (Lyon), T. Contini (Institut de Recherche en Astrophysique et Planétologie, CNRS, Toulouse, France; Université de Toulouse, France [IRAP]), A. Drake (Lyon), M. Franx (Leiden), S. Tacchella (ETH Zurich, Institute of Astronomy, Zurich, Switzerland [ETH]), J. Vernet (ESO, Garching, Germany), L. Wisotzki (Leibniz-Institut für Astrophysik Potsdam, Potsdam, Germany [AIP]), J. Blaizot (Lyon), N. Bouché (IRAP), R. Bouwens (Leiden), S. Cantalupo (ETH), C.M. Carollo (ETH), D. Carton (Leiden), J. Caruana (AIP), B. Clément (Lyon), S. Dreizler (Institut für Astrophysik, Universität Göttingen, Göttingen, Germany [AIG]), B. Epinat (IRAP; Aix Marseille Université, CNRS, Laboratoire d’Astrophysique de Marseille, Marseille, France), B. Guiderdoni (Lyon), C. Herenz (AIP), T.-O. Husser (AIG), S. Kamann (AIG), J. Kerutt (AIP), W. Kollatschny (AIG), D. Krajnovic (AIP), S. Lilly (ETH), T. Martinsson (Leiden), L. Michel-Dansac (Lyon), V. Patricio (Lyon), J. Schaye (Leiden), M. Shirazi (ETH), K. Soto (ETH), G. Soucail (IRAP), M. Steinmetz (AIP), T. Urrutia (AIP), P. Weilbacher (AIP) and T. de Zeeuw (ESO, Garching, Germany; Leiden).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. 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 a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1507/eso1507a.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

Images, Videos, Text, Credits: ESO/MUSE Consortium/R. Bacon/IAU and Sky & Telescope/R. Williams (STScI), the HDF-S Team, and NASA/ESA.

Greetings, Orbiter.ch

mercredi 25 février 2015

Try to contact aliens is not risky










SETI Institute logo.

February 25, 2015

Astrophysicists wishing for sending signals to establish contact with aliens has rejected fears that this initiative which could threaten Earth.

"For fifty years we pointed radio telescopes to the stars in search of signals from other civilizations, but without success," said Douglas Vakoch, a scientist at the SETI (Search for Extraterrestrial Intelligence), during a presentation at the Annual Conference of the American Society for the Advancement of Science (AAAS) meeting this week in San Jose, California. "With this Active SETI program, we reverse the process to take an active role in providing powerful information-rich signals to other worlds in the hope to have an answer," he added.


Image above: The 305-meter telescope at Arecibo Observatory is just one of a collection That Will SETI use to search nearby stars for electronic signals indicate indication That Could Intelligent life.

These messages would be sent to relatively nearby stellar systems with potentially habitable planets. According to these astrophysicists, such an approach is more promising than previous attempts to make contact with aliens, as the disk on board the two Voyager spacecraft, launched in 1977, containing sounds and images selected to be a portrait of the diversity of life and the terrestrial culture.

Radio signals have also been sent for this purpose in the cosmos. In 1999, Russian scientists sent their own messages with the telescope Yevpatoria in the Crimea, and in 2008, NASA, the US space agency has forwarded the Beatles song "Across the Universe" toward the North Star, a distance of 430 years light. Through the use of today's most powerful radio telescopes, Seth Shostak, director of the SETI Institute, said in the same statement Thursday that it would broadcast to the stars all the content of the Internet, which would allow another civilization would capture these signals to decipher all of human history and culture.


Images above: The Arecibo message and its primary objective: the globular cluster M13.

"Progress of future generations"

The researchers acknowledge that their project is controversial citing reservations including Stephen Hawking, for which such transmissions would be "irresponsible". The British astrophysicist highlighted the fact that human history provides many examples of tragic encounters for less advanced civilizations such as the Incas with the Spanish. But proponents Active SETI forcefully reject these arguments, which they fall under the "paranoia".


Images above: Front and reverse sides of the Golden Record on board the Voyager 1 & 2 spacecrafts.

Seth Shostak argues that "it is in any case too late to worry about signal our presence" to prospective AND bellicose. "Any sufficiently advanced extraterrestrial civilization to attack and vaporize the Earth can easily pick up our radio broadcasts, we broadcast since the Second World War," he noted. For him, if one wanted to prohibit the dissemination of signals in space, it would also prevent the use of military radar systems and airports, and why not lights of cities.

"Such actions undermine paranoid all the activities and progress of future human generations," he ruled. Dismissing paranoid accusations, David Brin, astrophysicist and author of science fiction, called for a moratorium before sending these messages. "We offer a call to an international consensus and public consultation before humanity will make an irreversible step, namely to report loudly our presence in the cosmos," said the writer in front of AAAS.

For more informqation about the Search for Extra-Terrestrial Intelligence (SETI), visit: http://www.seti.org/

Images, Text, Credits: AFP / SETI /NROA / R.Gralak/ NASA/Wikimedia/Orbiter.ch Aerospace.

Greetings, Orbiter.ch

Wilmore and Virts Complete Second Spacewalk










ISS - Expedition 42 Mission patch.

February 25, 2015


Image above: NASA astronaut Terry, Virts Flight Engineer of Expedition 42 is seen working to complete a cable routing task while near the forward facing port of the Harmony module on the International Space Station. Image Credit: NASA TV.

NASA astronauts Barry Wilmore and Terry Virts ended their spacewalk at 1:34 p.m. EST with the repressurization of the Quest airlock. Wilmore and Virts completed all the scheduled tasks for today. They completed rigging a series of power cables on Pressurized Mating Adapter-2, lubricated the Latching End Effecter of the space station’s Canadarm2 robotic arm, and prepared the Tranquility module for the station’s upcoming reconfiguration in preparation for the arrival of commercial crew vehicles later this decade. They also were able to complete get-ahead work for the installation during Sunday’s spacewalk of the Common Communications for Visiting Vehicles (C2V2) system by pre-staging wire-ties that will be used to secure some 400 feet of cable.

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Spacewalk continues prepping of ISS for new docking ports

The 6-hour, 43-minute spacewalk was the third for Wilmore and the second for Virts. Wilmore now has spent 19 hours and 58 minutes in the void of space during his three spacewalks. Virts has now spent 13 hours and 24 minutes outside during his two excursions. Crews have now spent a total of 1,165 hours and 51 minutes conducting space station assembly and maintenance during 186 spacewalks.


Image above: Spacewalkers Terry Virts and Barry Wilmore work outside Pressurized Mating Adapter-2. Image Credit: NASA TV.

The duo will venture outside the space station again on Sunday, March 1, to install the C2V2 equipment commercial spacecraft delivering crews to the space station will use to rendezvous and dock with the orbital laboratory. NASA TV coverage will begin at 6 a.m. Sunday ahead of a planned 7:10 a.m. start time for the spacewalk.

NASA astronaut and spacewalker Terry Virts reported seeing a small amount of water floating free in his helmet during airlock repressurization at the conclusion of Wednesday’s spacewalk. There was no report of water during the spacewalk itself, and the crew was never in any danger. After removing the helmet, Expedition 42 crew member Samantha Cristoforetti reported on the free floating water inside the helmet and indicated the helmet absorption pad was damp. Ground teams are currently analyzing the situation to confirm the source of the water.


Image above: (From left) Spacewalker Terry Virts, Italian astronaut Samantha Cristoforetti and cosmonaut Anton Shkaplerov are in the Quest airlock checking out the spacesuit helmet reported to have a small amount of water in it. Image Credit: NASA TV.

Virts was wearing spacesuit #3005, which experienced a similar issue after a spacewalk in December 2013.

The teams will carefully evaluate the spacesuit data and perform a detailed assessment prior to the next spacewalk. Virts and fellow spacewalker Barry Wilmore are scheduled to perform their third and final spacewalk on Sunday, March 1.

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Video, Text, Credits: NASA/NASA TV.

Greetings, Orbiter.ch

"Bright Spot' on Ceres Has Dimmer Companion












NASA - Dawn Mission patch.

February 25, 2015


Image above: This image was taken by NASA's Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 kilometers). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Dwarf planet Ceres continues to puzzle scientists as NASA's Dawn spacecraft gets closer to being captured into orbit around the object. The latest images from Dawn, taken nearly 29,000 miles (46,000 kilometers) from Ceres, reveal that a bright spot that stands out in previous images lies close to yet another bright area.

"Ceres' bright spot can now be seen to have a companion of lesser brightness, but apparently in the same basin. This may be pointing to a volcano-like origin of the spots, but we will have to wait for better resolution before we can make such geologic interpretations," said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.


Images above: These images of dwarf planet Ceres, processed to enhance clarity, were taken on Feb. 19, 2015, from a distance of about 29,000 miles (46,000 kilometers), by NASA's Dawn spacecraft. Dawn observed Ceres completing one full rotation, which lasted about nine hours. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Using its ion propulsion system, Dawn will enter orbit around Ceres on March 6. As scientists receive better and better views of the dwarf planet over the next 16 months, they hope to gain a deeper understanding of its origin and evolution by studying its surface. The intriguing bright spots and other interesting features of this captivating world will come into sharper focus.

"The brightest spot continues to be too small to resolve with our camera, but despite its size it is brighter than anything else on Ceres. This is truly unexpected and still a mystery to us," said Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research, Gottingen, Germany.


Images above: NASA's Dawn spacecraft obtained these uncropped images of dwarf planet Ceres on Feb. 19, 2015, from a distance of about 29,000 miles (46,000 kilometers). They are part of a series taken as Dawn observed Ceres completing one full rotation, which lasted about nine hours. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Dawn visited the giant asteroid Vesta from 2011 to 2012, delivering more than 30,000 images of the body along with many other measurements, and providing insights about its composition and geological history. Vesta has an average diameter of 326 miles (525 kilometers), while Ceres has an average diameter of 590 miles (950 kilometers). Vesta and Ceres are the two most massive bodies in the asteroid belt, located between Mars and Jupiter.

Dawn's mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK, Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team. For a complete list of acknowledgements, visit: http://dawn.jpl.nasa.gov/mission

For information about NASA's Dawn mission, visit: http://dawn.jpl.nasa.gov

Images (mentioned), Text, Credits: NASA/JPL/Elizabeth Landau.

Best regards, Orbiter.ch

NASA’s Chandra Finds Intriguing Member of Black Hole Family Tree












NASA - Chandra X-ray Observatory patch.

February 25, 2015

A newly discovered cosmic object may help provide answers to some long-standing questions about how black holes evolve and influence their surroundings, according to a new study using NASA’s Chandra X-ray Observatory.

“In paleontology, the discovery of certain fossils can help scientists fill in the evolutionary gaps between different dinosaurs,” said Mar Mezcua of the Harvard-Smithsonian Center for Astrophysics, who led the study. “We do the same thing in astronomy, but we often have to ‘dig’ up our discoveries in galaxies that are millions of light years away.”


Image above: A newly discovered object in the galaxy NGC 2276 may prove to be an important black hole that helps fill in the evolutionary story of these exotic objects. Image Credit: X-ray: NASA/CXC/SAO/M.Mezcua et al & NASA/CXC/INAF/A.Wolter.

The intriguing object, called NGC2276-3c, is located in an arm of the spiral galaxy NGC 2276, which is about 100 million light years from Earth. NGC2276-3c appears to be what astronomers call an “intermediate-mass black hole” (IMBH).

For many years, scientists have found conclusive evidence for smaller black holes that contain about five to thirty times the mass of the sun. There is also a lot of information about so-called supermassive holes that reside at the center of galaxies and weigh millions or even billions times the sun’s mass.

As their name suggests, IMBHs represent a class of black holes that fall in between these two well-established groups, with masses in the range of a few hundred to a few hundred thousand solar masses. One reason that IMBHs are important is that they could be the seeds from which supermassive black holes formed in the early universe.

“Astronomers have been looking very hard for these medium-sized black holes,” said co-author Tim Roberts of the University of Durham in the UK. “There have been hints that they exist, but the IMBHs have been acting like a long-lost relative that isn’t interested in being found.”

To learn about NGC2276-3c, the researchers observed it at almost the same time in X-rays with Chandra and in radio waves with the European Very Long Baseline Interferometry (VLBI) Network. The X-ray and radio data, along with an observed relation between radio and X-ray luminosities for sources powered by black holes, were used to estimate the black hole’s mass. A mass of about 50,000 times that of the sun was obtained, placing it in the range of IMBHs.

“We found that NGC2276-3c has traits similar to both stellar-mass black holes and supermassive black holes” said co-author Andrei Lobanov of the Max Planck Institute for Radio Astronomy in Bonn, Germany. “In other words, this object helps tie the whole black hole family together.”

In addition to its mass, another remarkable property of NGC2276-3c is that it has produced a powerful radio jet that extends up to 2,000 light years. The region along the jet that extends for about 1,000 light years from NGC2276-3c seems to be missing young stars. This provides evidence that the IMBH may have had a strong influence on its environment, as the jet could have cleared out a cavity in the gas and suppressed the formation of new stars. Further studies of the NGC2276-3c jet could provide insight into the potentially large effects that supermassive black hole seeds in the early universe have had on their surroundings.

NASA’s Chandra X-ray Observatory. Image Credits: NASA

The location of this IMBH in a spiral arm of NGC 2276 raises other questions. Was it formed within the galaxy, or did it come from the center of a dwarf galaxy that collided and merged with NGC 2276 in the past?

This IMBH is one of eight ultraluminous X-ray sources (ULXs) in NGC 2276 studied by Anna Wolter of the National Institute for Astrophysics (INAF) in Milan, Italy, and her colleagues. Hundreds of ULXs have been detected in the last 30 years; however, the nature of these sources is still a matter of debate, with some thought to contain IMBHs. Chandra observations show that one apparent ULX observed by ESA’s XMM-Newton is actually five separate ULXs, including NGC2276-3c. Wolter’s study concluded that about five to fifteen solar masses worth of stars are forming each year in NGC 2276. This high rate of star formation may have been triggered by a collision with a dwarf galaxy, supporting the merger idea for the IMBH’s origin.

The results from Mezcua and Wolter and their colleagues will appear in separate papers in the Monthly Notices of the Royal Astronomical Society. The Mezcua paper and Wolter paper are also available online. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

An interactive image, a podcast, and a video about these findings are available at: http://chandra.si.edu

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Mezcua paper: http://arxiv.org/abs/1501.04897

Wolter paper: http://arxiv.org/abs/1501.01994

Images (mentioned), Text, Credits: NASA/Marshall Space Flight Center/Janet Anderson.

Cheers, Orbiter.ch

New NASA Soil Moisture Mapper Completes Key Milestone












NASA - SMAP Mission patch.

February 25, 2015

Mission controllers at NASA's Jet Propulsion Laboratory in Pasadena, California, today sent commands to unfurl the massive 20-foot-wide (6-meter) reflector antenna on NASA’s new Soil Moisture Active Passive (SMAP) observatory, launched Jan. 31. The deployment of the mesh reflector antenna, which supports the collection of SMAP's radar and radiometer instrument measurements in space, marks a key milestone in commissioning the satellite. SMAP will soon begin its three-year science mission to map global soil moisture and detect whether soils are frozen or thawed.

SMAP will help scientists understand the links in Earth's water, energy and carbon cycles, help reduce uncertainties in predicting weather and climate, and enhance our ability to monitor and predict natural hazards such as floods and droughts.


Image above: NASA's Soil Moisture Active Passive (SMAP) mission will produce high-resolution global maps of soil moisture to track water availability around our planet and guide policy decisions. Image Credit: NASA/JPL-Caltech.

Today, an onboard pyro was fired to open restraints on the furled antenna, which then sprang partially open through the force of stored energy. A motor then wound a cable to pull the reflector open to its full circular configuration. The total procedure took approximately 33 minutes. Initial data indicate the antenna deployment went as planned. Mission managers are downloading onboard inertial measurement unit data and other telemetry to confirm the antenna successfully deployed. The assessment of this more detailed data and telemetry is expected to be completed later this week. The reflector antenna and its boom, which holds the reflector in position and reduces deflections caused by the antenna as it spins, were designed and built by Astro Aerospace, a Northrop Grumman Corporation company located in Carpinteria, California, under subcontract to JPL.

In about a month, after additional tests and maneuvers to adjust the observatory to its final science orbit, the antenna will be spun up to nearly 15 revolutions per minute in a two-stage process. By rotating, the antenna will be able to measure a 620-mile (1,000-kilometer) swath of Earth below, allowing SMAP to map the globe every two to three days.

For more information on SMAP, visit: http://www.nasa.gov/smap

For more information about NASA's Earth science programs, visit: http://www.nasa.gov/earthrightnow

Image (mentioned), Text, Credits: NASA/JPL/Alan Buis.

Greetings, Orbiter.ch

mardi 24 février 2015

Timelapse: LHC experiments prepare for restart












CERN - European Organization for Nuclear Research logo.

February 24, 2015

video
ALMOST READY TO RESTART

The LHC is preparing to restart at almost double the collision energy of its previous run. The new energy will allow physicists to check previously untestable theories, and explore new frontiers in particle physics.

When the LHC is on, counter-rotating beams of particles will be made to collide at four interaction points 100 metres underground, around which sit the huge detectors ALICE, ATLAS, CMS and LHCb.

In the video above, engineers and technicians prepare these four detectors to receive the showers of particles that will be created in collisions at energies of 13 TeV. The giant endcaps of the ATLAS detector are back in position and the wheels of the CMS detector are moving it back into its "closed" configuration. The huge red door of the ALICE experiment is closed up ready for restart, and the access door to the LHC tunnel is sealed with concrete blocks.

Large Hadron Collider (LHC)

The LHC will start up again end of March. Read about how the machine has changed since its previous run: http://press.web.cern.ch/backgrounders/lhc-season-2-stronger-machine

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

CERN's two-year shutdown drawing to a close: http://orbiterchspacenews.blogspot.ch/2015/02/cerns-two-year-shutdown-drawing-to-close.html

For more information about the European Organization for Nuclear Research (CERN), visit: http://home.web.cern.ch/

Image, Video, Text, Credits: CERN/Cian O'Luanaigh.

Best regards, Orbiter.ch

Curiosity Self-Portrait at 'Mojave' Site on Mount Sharp












NASA - Mars Science Laboratory (MSL) patch.

February 24, 2015

Curiosity Self-Portrait at 'Mojave' Site on Mount Sharp

This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the "Mojave" site, where its drill collected the mission's second taste of Mount Sharp.

The scene combines dozens of images taken during January 2015 by the Mars Hand Lens Imager (MAHLI) camera at the end of the rover's robotic arm.  The pale "Pahrump Hills" outcrop surrounds the rover, and the upper portion of Mount Sharp is visible on the horizon.  Darker ground at upper right and lower left holds ripples of wind-blown sand and dust.

An annotated version, labels several of the sites Curiosity has investigated during three passes up the Pahrump Hills outcrop examining the outcrop at increasing levels of detail. The rover used its sample-collecting drill at "Confidence Hills" as well as at Mojave, and in late February was assessing "Telegraph Peak" as a third drilling site.

 Curiosity Self-Portrait at 'Mojave' Site on Mount Sharp annotated (Click on the image for enlarge)

The view does not include the rover's robotic arm.  Wrist motions and turret rotations on the arm allowed MAHLI to acquire the mosaic's component images. The arm was positioned out of the shot in the images, or portions of images, that were used in this mosaic. This process was used previously in acquiring and assembling Curiosity self-portraits taken at sample-collection sites "Rock Nest" (http://photojournal.jpl.nasa.gov/catalog/PIA16468), "John Klein" (http://photojournal.jpl.nasa.gov/catalog/PIA16937) and "Windjana" (http://photojournal.jpl.nasa.gov/catalog/PIA18390).

Curiosity used its drill to collect a sample of rock powder from target "Mojave 2" at this site on Jan. 31, 2015.  The full-depth, sample-collection hole and the shallower preparation test hole beside it are visible in front of the rover in this self-portrait, and in more detail at http://photojournal.jpl.nasa.gov/catalog/PIA19115 .  The Mojave site is in the "Pink Cliffs" portion of the Pahrump Hills outcrop. The outcrop is an exposure of the Murray formation, which forms the basal geological layer of Mount Sharp.  Views of Pahrump Hills from other angles are at http://photojournal.jpl.nasa.gov/catalog/PIA19039 and the inset at http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=6968 .

The frames showing the rover in this mosaic were taken during the 868th Martian day, or sol, of Curiosity's work on Mars (Jan. 14, 2015).  Additional frames around the edges to extend the amount of terrain included in the scene were taken on Sol 882 (Jan. 29, 2015).  The frames showing the drill holes were taken on Sol 884 (Jan. 31, 2015).

For scale, the rover's wheels are 20 inches (50 centimeters) in diameter and about 16 inches (40 centimeters) wide.  The drilled holes in the rock are 0.63 inch (1.6 centimeters) in diameter.

MAHLI was built by Malin Space Science Systems, San Diego. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover.

More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/.

Images, Text, Credits: NASA/JPL-Caltech/MSSS.

Greetings, Orbiter.ch

Satellite Reveals How Much Saharan Dust Feeds Amazon’s Plants








NASA/CNES - CALIPSO logo.

February 24, 2015

What connects Earth's largest, hottest desert to its largest tropical rain forest?

The Sahara Desert is a near-uninterrupted brown band of sand and scrub across the northern third of Africa. The Amazon rain forest is a dense green mass of humid jungle that covers northeast South America. But after strong winds sweep across the Sahara, a tan cloud rises in the air, stretches between the continents, and ties together the desert and the jungle. It’s dust. And lots of it.

For the first time, a NASA satellite has quantified in three dimensions how much dust makes this trans-Atlantic journey. Scientists have not only measured the volume of dust, they have also calculated how much phosphorus – remnant in Saharan sands from part of the desert’s past as a lake bed – gets carried across the ocean from one of the planet’s most desolate places to one of its most fertile.

video
Satellite Tracks Saharan Dust to Amazon in 3-D

Video above: For the first time, a NASA satellite has quantified in three dimensions how much dust makes the trans-Atlantic journey from the Sahara Desert the Amazon rain forest. Among this dust is phosphorus, an essential nutrient that acts like a fertilizer, which the Amazon depends on in order to flourish. Video Credit: NASA's Goddard Space Flight Center.

A new paper published Feb. 24 in Geophysical Research Letters, a journal of the American Geophysical Union, provides the first satellite-based estimate of this phosphorus transport over multiple years, said lead author Hongbin Yu, an atmospheric scientist at the University of Maryland who works at NASA's Goddard Space Flight Center in Greenbelt, Maryland. A paper published online by Yu and colleagues Jan. 8 in Remote Sensing of the Environment provided the first multi-year satellite estimate of overall dust transport from the Sahara to the Amazon.

This trans-continental journey of dust is important because of what is in the dust, Yu said. Specifically the dust picked up from the Bodélé Depression in Chad, an ancient lake bed where rock minerals composed of dead microorganisms are loaded with phosphorus. Phosphorus is an essential nutrient for plant proteins and growth, which the Amazon rain forest depends on in order to flourish.

Nutrients – the same ones found in commercial fertilizers – are in short supply in Amazonian soils. Instead they are locked up in the plants themselves. Fallen, decomposing leaves and organic matter provide the majority of nutrients, which are rapidly absorbed by plants and trees after entering the soil. But some nutrients, including phosphorus, are washed away by rainfall into streams and rivers, draining from the Amazon basin like a slowly leaking bathtub.

The phosphorus that reaches Amazon soils from Saharan dust, an estimated 22,000 tons per year, is about the same amount as that lost from rain and flooding, Yu said. The finding is part of a bigger research effort to understand the role of dust and aerosols in the environment and on local and global climate.

Dust in the Wind

"We know that dust is very important in many ways. It is an essential component of the Earth system. Dust will affect climate and, at the same time, climate change will affect dust," said Yu. To understand what those effects may be, "First we have to try to answer two basic questions. How much dust is transported? And what is the relationship between the amount of dust transport and climate indicators?"

The new dust transport estimates were derived from data collected by a lidar instrument on NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, or CALIPSO, satellite from 2007 though 2013.


Image above: The lidar instrument aboard the CALIPSO satellite sends out pulses of light that bounce off particles in the atmosphere and back to the satellite. It distinguishes dust from other particles based on optical properties. Image Credit: NASA Goddard's Scientific Visualization Studio.

The data show that wind and weather pick up on average 182 million tons of dust each year and carry it past the western edge of the Sahara at longitude 15W. This volume is the equivalent of 689,290 semi trucks filled with dust. The dust then travels 1,600 miles across the Atlantic Ocean, though some drops to the surface or is flushed from the sky by rain. Near the eastern coast of South America, at longitude 35W, 132 million tons remain in the air, and 27.7 million tons – enough to fill 104,908 semi trucks – fall to the surface over the Amazon basin. About 43 million tons of dust travel farther to settle out over the Caribbean Sea, past longitude 75W.

Yu and colleagues focused on the Saharan dust transport across the Atlantic Ocean to South America and then beyond to the Caribbean Sea because it is the largest transport of dust on the planet.

Dust collected from the Bodélé Depression and from ground stations on Barbados and in Miami give scientists an estimate of the proportion of phosphorus in Saharan dust. This estimate is used to calculate how much phosphorus gets deposited in the Amazon basin from this dust transport.

The seven-year data record, while too short for looking at long-term trends, is nevertheless very important for understanding how dust and other aerosols behave as they move across the ocean, said Chip Trepte, project scientist for CALIPSO at NASA's Langley Research Center in Virginia, who was not involved in either study.

"We need a record of measurements to understand whether or not there is a fairly robust, fairly consistent pattern to this aerosol transport," he said.


Image above: CALIPSO, launched in 2006, flies in formation at more than fifteen thousand miles per hour, along with four other Earth Observing System satellites in NASA's "A-Train"constellation. Image Credit: NASA.

Looking at the data year by year shows that that pattern is actually highly variable. There was an 86 percent change between the highest amount of dust transported in 2007 and the lowest in 2011, Yu said.

Why so much variation? Scientists believe it has to do with the conditions in the Sahel, the long strip of semi-arid land on the southern border of the Sahara. After comparing the changes in dust transport to a variety of climate factors, the one Yu and his colleagues found a correlation to was the previous year's Sahel rainfall. When Sahel rainfall increased, the next year's dust transport was lower.

The mechanism behind the correlation is unknown, Yu said. One possibility is that increased rainfall means more vegetation and less soil exposed to wind erosion in the Sahel. A second, more likely explanation is that the amount of rainfall is related to the circulation of winds, which are what ultimately sweep dust from both the Sahel and Sahara into the upper atmosphere where it can survive the long journey across the ocean.

CALIPSO collects "curtains" of data that show valuable information about the altitude of dust layers in the atmosphere. Knowing the height at which dust travels is important for understanding, and eventually using computers to model, where that dust will go and how the dust will interact with Earth's heat balance and clouds, now and in future climate scenarios.

"Wind currents are different at different altitudes," said Trepte. "This is a step forward in providing the understanding of what dust transport looks like in three dimensions, and then comparing with these models that are being used for climate studies."

Climate studies range in scope from global to regional changes, such as those that may occur in the Amazon in coming years. In addition to dust, the Amazon is home to many other types of aerosols like smoke from fires and biological particles, such as bacteria, fungi, pollen, and spores released by the plants themselves. In the future, Yu and his colleagues plan to explore the effects of those aerosols on local clouds – and how they are influenced by dust from Africa.

"This is a small world," Yu said, "and we're all connected together."

For more information about NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, or CALIPSO, visit: http://www.nasa.gov/mission_pages/calipso/main/

Images (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center/NASA's Earth Science News Team/Ellen Gray.

Greetings, Orbiter.ch