samedi 31 janvier 2015

SMAP Launches on Mission to Study Soil Moisture











NASA - SMAP Mission patch.

January 31, 2015

NASA’s Soil Moisture Active Passive (SMAP) spacecraft launched!

NASA’s Soil Moisture Active Passive successfully lifted off from Vandenberg Air Force Base in California at 9:22 a.m. EST Saturday. SMAP is a three-year mission to study and map the Earth’s soil moisture, which regulates plant growth and has impacts on weather, emergency management and more.

video
NASA Earth Science Mission Launches

NASA’s Soil Moisture Active Passive (SMAP) spacecraft launched Jan. 31 from California’s Vandenberg Air Force Base. SMAP is the first U.S. Earth-observing satellite designed to collect global observations of surface soil moisture.

The mission’s high resolution space-based measurements of soil moisture will give scientists a new capability to better predict natural hazards of extreme weather and improve our understanding of Earth’s water, energy and carbon cycles.


Image above: Artist’s rendering of NASA's Soil Moisture Active Passive (SMAP) spacecraft in orbit.

Remote sensing instruments are called “active” when they emit their own signals and “passive” when they record signals that already exist. The mission's science instrument ropes together a sensor of each type to corral the highest-resolution, most accurate measurements ever made of soil moisture -- a tiny fraction of Earth's water that has a disproportionately large effect on weather and agriculture.

To enable the mission to meet its accuracy needs while covering the globe every three days or less, SMAP engineers at NASA's Jet Propulsion Laboratory in Pasadena, California, designed and built the largest rotating antenna that could be stowed into a space of only one foot by four feet (30 by 120 centimeters) for launch. The dish is 19.7 feet (6 meters) in diameter.

Related link:

Technology Innovations Spin NASA's SMAP into Space: http://orbiterchspacenews.blogspot.ch/2015/01/technology-innovations-spin-nasas-smap.html

For more about the SMAP mission, visit: http://www.nasa.gov/smap/

Images, Video, Text, Credits: NASA/NASA TV.

Greetings, Orbiter.ch

vendredi 30 janvier 2015

Astronomers Discover Ancient System with Five Small Planets












NASA - Kepler Space Telescope patch.

January 30, 2015

Astronomers using data from NASA's Kepler mission have discovered a planetary system of five small planets dating back to when the Milky Way galaxy was a youthful two billion years old.

The tightly packed system, named Kepler-444, is home to five planets that range in size, the smallest comparable to the size of Mercury and the largest to Venus. All five planets orbit their sun-like star in less than ten days, which makes their orbits much closer than Mercury's sweltering 88-day orbit around the sun.


Image above: The tightly packed system, named Kepler-444, is home to five small planets in very compact orbits. The planets were detected from the dimming that occurs when they transit the disc of their parent star, as shown in this artist's conception. Image Credit: Tiago Campante/Peter Devine.

"While this star formed a long time ago, in fact before most of the stars in the Milky Way, we have no indication that any of these planets have now or ever had life on them," said Steve Howell, Kepler/K2 project scientist at NASA's Ames Research Center in Moffett Field, California. "At their current orbital distances, life as we know it could not exist on these ancient worlds."

Kepler-444 formed 11.2 billion years ago, when the universe was less than 20 percent its current age. This makes Kepler-444 the oldest known system of terrestrial-size planets, two and a half times older than the Earth.

To determine the age of the star and thus its planets, scientists measured the very small change in brightness of the host star caused by pressure waves within the star. The boiling motion beneath the surface of the star generates these pressure waves, affecting the star's temperature and luminosity. These fluctuations lead to miniscule changes or variations in a star's brightness. This study of the interior of stars is called asteroseismology and allows the researchers to measure the diameter, mass and age of a star.

Artist's view of Kepler Space Telescope. Image Credit: NASA

The Kepler-444 system is approximately 117 light-years away toward the constellation Lyra. A paper reporting this discovery is published in The Astrophysical Journal.

For more information on the discovery, see the University of Birmingham's press release: http://www.birmingham.ac.uk/news/latest/2015/01/discovery-of-replica-solar-system-27-01-15.aspx

Ames is responsible for Kepler's mission operations, ground system development and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colorado, developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The NASA Exoplanet Archive in Pasadena and the Space Telescope Science Institute in Baltimore archive, host and distribute Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate in Washington.

For more information about the Kepler mission, visit: http://www.nasa.gov/kepler

Related link:

The Astrophysical Journal: http://arxiv.org/abs/1501.06227

Images (mentioned), Text, Credits: NASA/Ames Research Center/Michele Johnson.

Greetings, Orbiter.ch

Planck: gravitational waves remain elusive












ESA - Planck Mission patch.

30 January 2015

Despite earlier reports of a possible detection, a joint analysis of data from ESA’s Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves.

The Universe began about 13.8 billion years ago and evolved from an extremely hot, dense and uniform state to the rich and complex cosmos of galaxies, stars and planets we see today.

An extraordinary source of information about the Universe’s history is the Cosmic Microwave Background, or CMB, the legacy of light emitted only 380 000 years after the Big Bang.

Planck view of BICEP2 field

ESA’s Planck satellite observed this background across the whole sky with unprecedented accuracy, and a broad variety of new findings about the early Universe has already been revealed over the past two years.

But astronomers are still digging ever deeper in the hope of exploring even further back in time: they are searching for a particular signature of cosmic ‘inflation’ – a very brief accelerated expansion that, according to current theory, the Universe experienced when it was only the tiniest fraction of a second old.

This signature would be seeded by gravitational waves, tiny perturbations in the fabric of space-time, that astronomers believe would have been generated during the inflationary phase.

Interestingly, these perturbations should leave an imprint on another feature of the cosmic background: its polarisation.

When light waves vibrate preferentially in a certain direction, we say the light is polarised.

The CMB is polarised, exhibiting a complex arrangement across the sky. This arises from the combination of two basic patterns: circular and radial (known as E-modes), and curly (B-modes).

Planck and the cosmic microwave background

Different phenomena in the Universe produce either E- or B-modes on different angular scales and identifying the various contributions requires extremely precise measurements. It is the B-modes that could hold the prize of probing the Universe’s early inflation.

“Searching for this unique record of the very early Universe is as difficult as it is exciting, since this subtle signal is hidden in the polarisation of the CMB, which itself only represents only a feeble few percent of the total light,” says Jan Tauber, ESA’s project scientist for Planck.

Planck is not alone in this search. In early 2014, another team of astronomers presented results based on observations of the polarised CMB on a small patch of the sky performed 2010–12 with BICEP2, an experiment located at the South Pole. The team also used preliminary data from another South Pole experiment, the Keck Array.

They found something new: curly B-modes in the polarisation observed over stretches of the sky a few times larger than the size of the full Moon.

The BICEP2 team presented evidence favouring the interpretation that this signal originated in primordial gravitational waves, sparking an enormous response in the academic community and general public.

However, there is another contender in this game that can produce a similar effect: interstellar dust in our Galaxy, the Milky Way.

The Milky Way is pervaded by a mixture of gas and dust shining at similar frequencies to those of the CMB, and this foreground emission affects the observation of the most ancient cosmic light. Very careful analysis is needed to separate the foreground emission from the cosmic background.

Critically, interstellar dust also emits polarised light, thus affecting the CMB polarisation as well.

“When we first detected this signal in our data, we relied on models for Galactic dust emission that were available at the time,” says John Kovac, a principal investigator of BICEP2 at Harvard University, in the USA.

Planck view of Galactic dust

“These seemed to indicate that the region of the sky chosen for our observations had dust polarisation much lower than the detected signal.”

The two ground-based experiments collected data at a single microwave frequency, making it difficult to separate the emissions coming from the Milky Way and the background.

On the other hand, Planck observed the sky in nine microwave and sub-millimetre frequency channels, seven of which were also equipped with polarisation-sensitive detectors. By careful analysis, these multi-frequency data can be used to separate the various contributions.

The BICEP2 team had chosen a field where they believed dust emission would be low, and thus interpreted the signal as likely to be cosmological.

However, as soon as Planck’s maps of the polarised emission from Galactic dust were released, it was clear that this foreground contribution could be much higher than previously expected.

In fact, in September 2014, Planck revealed for the first time that the polarised emission from dust is significant over the entire sky, and comparable to the signal detected by BICEP2 even in the cleanest regions.

So, the Planck and BICEP2 teams joined forces, combining the satellite’s ability to deal with foregrounds using observations at several frequencies – including those where dust emission is strongest – with the greater sensitivity of the ground-based experiments over limited areas of the sky, thanks to their more recent, improved technology. By then, the full Keck Array data from 2012 and 2013 had also become available.

“This joint work has shown that the detection of primordial B-modes is no longer robust once the emission from Galactic dust is removed,” says Jean-Loup Puget, principal investigator of the HFI instrument on Planck at the Institut d’Astrophysique Spatiale in Orsay, France.

“So, unfortunately, we have not been able to confirm that the signal is an imprint of cosmic inflation.”

Another source of B-mode polarisation, dating back to the early Universe, was detected in this study, but on much smaller scales on the sky.

This signal, first discovered in 2013, is not a direct probe of the inflationary phase but is induced by the cosmic web of massive structures that populate the Universe and change the path of the CMB photons on their way to us.

Deflecting light from the Big Bang

This effect is called ‘gravitational lensing’, since it is caused by massive objects bending the surrounding space and thus deflecting the trajectory of light much like a magnifying glass does. The detection of this signal using Planck, BICEP2 and the Keck Array together is the strongest yet.

As for signs of the inflationary period, the question remains open.

“While we haven’t found strong evidence of a signal from primordial gravitational waves in the best observations of CMB polarisation that are currently available, this by no means rules out inflation,” says Reno Mandolesi, principal investigator of the LFI instrument on Planck at University of Ferrara, Italy.

In fact, the joint study sets an upper limit on the amount of gravitational waves from inflation, which might have been generated at the time but at a level too low to be confirmed by the present analysis.

“This analysis shows that the amount of gravitational waves can probably be no more than about half the observed signal,” says Clem Pryke, a principal investigator of BICEP2 at University of Minnesota, in the USA.

“The new upper limit on the signal due to gravitational waves agrees well with the upper limit that we obtained earlier with Planck using the temperature fluctuations of the CMB,” says Brendan Crill, a leading member of both the Planck and BICEP2 teams from NASA’s Jet Propulsion Laboratory in the USA.

“The gravitational wave signal could still be there, and the search is definitely on.”

Notes for Editors

“A Joint Analysis of BICEP2/Keck Array and Planck Data” by the BICEP2/Keck and Planck collaboration has been submitted to the journal Physical Review Letters.

The study combines data from ESA’s Planck satellite and from the US National Science Foundation ground-based experiments BICEP2 and the Keck Array, at the South Pole.

The analysis is based on observations of the CMB polarisation on a 400 square degree patch of the sky. The Planck data cover frequencies between 30 GHz and 353 GHz, while the BICEP2 and Keck Array data were taken at a frequency of 150 GHz.

A public release of Planck data products will follow next week.

More about Planck

Launched in 2009, Planck was designed to map the sky in nine frequencies using two state-of-the-art instruments: the Low Frequency Instrument, which includes three frequency bands in the range 30–70 GHz, and the High Frequency Instrument, which includes six frequency bands in the range 100–857 GHz.

HFI completed its survey in January 2012, while LFI continued to make science observations until 3 October 2013, before being switched off on 19 October 2013. Seven of Planck’s nine frequency channels were equipped with polarisation-sensitive detectors.

The Planck Scientific Collaboration consists of all the scientists who have contributed to the development of the mission, and who participate in the scientific exploitation of the data during the proprietary period. These scientists are members of one or more of four consortia: the LFI Consortium, the HFI Consortium, the DK-Planck Consortium, and ESA's Planck Science Office. The two European-led Planck Data Processing Centres are in Paris, France and Trieste, Italy.

The LFI consortium is led by N. Mandolesi, Università degli Studi di Ferrara, Italy (deputy PI: M. Bersanelli, Università degli Studi di Milano, Italy), and was responsible for the development and operation of LFI.

The HFI consortium is led by J.L. Puget, Institut d’Astrophysique Spatiale in Orsay, France (deputy PI: F. Bouchet, Institut d’Astrophysique de Paris, France), and was responsible for the development and operation of HFI.

Planck Toolkit:

Planck toolkit introduction: http://www.esa.int/Our_Activities/Space_Science/Planck/Planck_Toolkit_introduction

Planck and the CMB: http://www.esa.int/Our_Activities/Space_Science/Planck/Planck_and_the_cosmic_microwave_background

CMB and inflation: http://www.esa.int/Our_Activities/Space_Science/Planck/The_cosmic_microwave_background_and_inflation

CMB and the distribution of matter: http://www.esa.int/Our_Activities/Space_Science/Planck/The_cosmic_microwave_background_and_the_distribution_of_matter_in_the_Universe

Tools to study the distribution of matter: http://www.esa.int/Our_Activities/Space_Science/Planck/Tools_to_study_the_distribution_of_matter_in_the_Universe

History of cosmic structure formation: http://www.esa.int/Our_Activities/Space_Science/Planck/History_of_cosmic_structure_formation

Effect of cosmic structure on CMB: http://www.esa.int/Our_Activities/Space_Science/Planck/The_effect_of_cosmic_structure_on_the_cosmic_microwave_background

In depth:

Planck in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=17

Planck Science Team: http://www.rssd.esa.int/index.php?project=Planck

Planck cosmology highlights: http://sci.esa.int/planck/53103

Planck cosmic structure highlights: http://sci.esa.int/planck/53104

Planck Milky Way highlights: http://sci.esa.int/planck/53105

Images, Text, Credits: ESA/Planck Collaboration/D. Ducros. Acknowledgment: M.-A. Miville-Deschênes, CNRS – Institut d’Astrophysique Spatiale, Université Paris-XI, Orsay, France.

Greetings, Orbiter.ch

jeudi 29 janvier 2015

The tell-tale signs of a galactic merger












ESA - Hubble Space Telescope logo.

29 January 2015

Hubble image of NGC 7714

The NASA/ESA Hubble Space Telescope has captured this striking view of spiral galaxy NGC 7714. This galaxy has drifted too close to another nearby galaxy and the dramatic interaction has twisted its spiral arms out of shape, dragged streams of material out into space, and triggered bright bursts of star formation.

NGC 7714 is a spiral galaxy at 100 million light-years from Earth — a relatively close neighbour in cosmic terms.

The galaxy has witnessed some violent and dramatic events in its recent past. Tell-tale signs of this brutality can be seen in NGC 7714's strangely shaped arms, and in the smoky golden haze that stretches out from the galactic centre.

Wide-field image of NGC 7714 (ground-based image)

So what caused this disfigurement? The culprit is a smaller companion named NGC 7715, which lies just out of the frame of this image — but is visible in the wider-field DSS image. The two galaxies [1] drifted too close together between 100 and 200 million years ago, and began to drag at and disrupt one another’s structure and shape.

As a result, a ring and two long tails of stars have emerged from NGC 7714, creating a bridge between the two galaxies. This bridge acts as a pipeline, funnelling material from NGC 7715 towards its larger companion and feeding bursts of star formation. Most of the star-forming activity is concentrated at the bright galactic centre, although the whole galaxy is sparking new stars.

video
Panning across NGC 7714

Astronomers characterise NGC 7714 as a typical Wolf-Rayet starburst galaxy. This is due to the stars within it; a large number of the new stars are of the Wolf-Rayet type — extremely hot and bright stars that begin their lives with dozens of times the mass of the Sun, but lose most of it very quickly via powerful winds.

video
Zooming in on NGC 7714

This Hubble image is a composite of data capturing a broad range of wavelengths, revealing the correlation of the gas clouds and stars in the galaxy. This new picture not only reveals the intricate structure of NGC 7714, but also shows many other objects that are much further away. These background galaxies resemble faint smudges of light, some of them with spiral forms.

Notes for editors:

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

[1] The interacting pair formed by NGC 7714 and NGC 7715 is named Arp 284.

Link:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Images, Text, Credits: ESA/NASA/Acknowledgement: A. Gal-Yam (Weizmann Institute of Science)/Digitized Sky Survey 2/Videos: NASA/ESA/Digitized Sky Survey 2 and A. Fuji/Music: movetwo.

Best regards, Orbiter.ch

mercredi 28 janvier 2015

The Mouth of the Beast












ESO - European Southern Observatory logo.

28 January 2015

VLT images cometary globule CG4

 VLT image of the cometary globule CG4

Like the gaping mouth of a gigantic celestial creature, the cometary globule CG4 glows menacingly in this new image from ESO’s Very Large Telescope. Although it appears to be big and bright in this picture, this is actually a faint nebula, which makes it very hard for amateur astronomers to spot. The exact nature of CG4 remains a mystery.

In 1976 several elongated comet-like objects were discovered on pictures taken with the UK Schmidt Telescope in Australia. Because of their appearance, they became known as cometary globules even though they have nothing in common with comets. They were all located in a huge patch of glowing gas called the Gum Nebula. They had dense, dark, dusty heads and long, faint tails, which were generally pointing away from the Vela supernova remnant located at the centre of the Gum Nebula. Although these objects are relatively close by, it took astronomers a long time to find them as they glow very dimly and are therefore hard to detect.

The cometary globule CG4 in the constellation of Puppis

The object shown in this new picture, CG4, which is also sometimes referred to as God’s Hand, is one of these cometary globules. It is located about 1300 light-years from Earth in the constellation of Puppis (The Poop, or Stern).

The head of CG4, which is the part visible on this image and resembles the head of the gigantic beast, has a diameter of 1.5 light-years. The tail of the globule — which extends downwards and is not visible in the image — is about eight light-years long. By astronomical standards this makes it a comparatively small cloud.

Wide-field view of the sky around the cometary globule CG4

The relatively small size is a general feature of cometary globules. All of the cometary globules found so far are isolated, relatively small clouds of neutral gas and dust within the Milky Way, which are surrounded by hot ionised material.

The head part of CG4 is a thick cloud of gas and dust, which is only visible because it is illuminated by the light from nearby stars. The radiation emitted by these stars is gradually destroying the head of the globule and eroding away the tiny particles that scatter the starlight. However, the dusty cloud of CG4 still contains enough gas to make several Sun-sized stars and indeed, CG4 is actively forming new stars, perhaps triggered as radiation from the stars powering the Gum Nebula reached CG4.

video
Zooming in on the cometary globule CG4

Why CG4 and other cometary globules have their distinct form is still a matter of debate among astronomers and two theories have developed. Cometary globules, and therefore also CG4, could originally have been spherical nebulae, which were disrupted and acquired their new, unusual form because of the effects of a nearby supernova explosion. Other astronomers suggest, that cometary globules are shaped by stellar winds and ionising radiation from hot, massive OB stars. These effects could first lead to the bizarrely (but appropriately!) named formations known as elephant trunks and then eventually cometary globules.

To find out more, astronomers need to find out the mass, density, temperature, and velocities of the material in the globules. These can be determined by the measurements of molecular spectral lines which are most easily accessible at millimetre wavelengths — wavelengths at which telescopes like the Atacama Large Millimeter/submillimeter Array (ALMA) operate.

video
Panning over a VLT image of the cometary globule CG4

This picture comes from the ESO Cosmic Gems programme, an outreach initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

More information:

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 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 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:

ESO Cosmic Gems programme: http://www.eso.org/public/outreach/gems.html

Photos of the Very Large Telescope: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Very%20Large%20Telescope

Photos from the Very Large Telescope: http://www.eso.org/public/images/archive/search/?adv=&facility=31

Images, Text, Credits: ESO/IAU and Sky & Telescope/Digitized Sky Survey 2/Videos: ESO/J.Perez/Digitized Sky Survey 2/N. Risinger (skysurvey.org). Music: movetwo.

Best regards, Orbiter.ch

mardi 27 janvier 2015

NASA and NOAA's Nighttime and Daytime Views of the Blizzard of 2015













NASA logo / NOAA logo.

January 27, 2015


Image above: On January 27, 2015 at 17:35 UTC (12:35 p.m. EST) NOAA's Geostationary Operational Environmental or GOES- East satellite captured an image of the nor'easter over New England. Image Credit: NASA/NOAA GOES Project.

NASA and NOAA have provided night-time and daytime views of the Blizzard of 2015 from the Suomi NPP and the GOES-East satellites.

A combination of the day-night band and high resolution infrared imagery from the NASA-NOAA's Suomi NPP satellite showed the historic blizzard near peak intensity as it moves over the New York through Boston Metropolitan areas at 06:45Z (1:45 a.m. EST) on January 27, 2015. The nighttime lights of the region were blurred by the high cloud tops associated with the most intense parts of the storm.

The center of the low pressure center was about 85 miles southeast of Nantucket, Massachusetts at 9:00 a.m. EST and had an estimated pressure of 975 millibars. The center of the storm was moving in a north-northeasterly direction.

At 10 a.m. EST, the National Weather Service noted "the powerful nor'easter that brought moderate to heavy snowfall and blizzard conditions to the Northeast on Monday will continue to affect the region on Tuesday, with heavy snow and blizzard conditions expected from eastern Long Island to Maine as the system slowly moves to the northeast. Snow and strong winds will being tapering off from south to north Tuesday night into Wednesday morning."


Image above: A combination of the day-night band and high resolution infrared imagery from the NASA-NOAA's Suomi NPP satellite showed the historic blizzard near peak intensity as it moves over the New York through Boston Metropolitan areas at 06:45Z (1:45 a.m. EST) on January 27, 2015. Image Credit: NOAA/NASA.

Later on January 27, 2015 at 17:35 UTC (12:35 p.m. EST) NOAA's Geostationary Operational Environmental or GOES-East satellite captured an image of the nor'easter over New England. The image was created by the NASA/NOAA GOES Project and showed the clouds associated with the nor'easter blanketing New England.  An occluded front extended north and eastward out of the low pressure area's center out into the Atlantic Ocean.

GOES satellites provide the kind of continuous monitoring necessary for intensive data analysis. Geostationary describes an orbit in which a satellite is always in the same position with respect to the rotating Earth. This allows GOES to hover continuously over one position on Earth's surface, appearing stationary. As a result, GOES provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms and hurricanes.

video
 2015 Blizzard – Time-Lapse video from International Space Station

For updated information about the storm system, visit NOAA's NWS website: http://www.weather.gov

For more information about GOES satellites, visit: http://www.goes.noaa.gov/  or http://goes.gsfc.nasa.gov/

For more information about Suomi NPP, visit: http://www.jpss.noaa.gov and  http://npp.gsfc.nasa.gov/

Images (mentioned), Video, Text, Credits: NASA TV/NASA's Goddard Space Flight Center/Rob Gutro.

Greetings, Orbiter.ch

Some Tiger's will can not be repaired












Swiss Air Force patch.

January 27, 2015

The Swiss army is not yet certain to repair combat aircraft that presented cracks at the beginning of the year.

Air Force first want to complete the inspection conducted on all devices before making a decision.

Northrop F-5E Tiger II Swiss Air Force

Five fighters have yet to be examined and are temporarily not allowed to fly. Cracks were detected on time for four fighters, detailed the Commander of the Swiss Air Forces Aldo Schellenberg speaking in an interview published Sunday in the weekly "Zentralschweiz am Sonntag".

If it turns out that additional jets for cracks, the four damaged units would likely be stored in the shed. This is already the case for 18 of the 54 Tiger's.

The price of a possible repair of cracked Tiger is not yet established, recognized Mr. Schellenberg. Their control costs about half a million Swiss francs. Models with two seats are not affected by the review, as already indicated in mid-January.

Northrop F-5E Tiger II Swiss Air Force two-seater

Editor notes:

Another demonstration of the disastrous management of the Military Department of Defense. Government headed by the Defence Minister Ueli Maurer, if not repair these fighters is a "political tactic" to again challenge the vote of the people of Switzerland against the purchase of the Gripen (bad choice of fighter) and put the country with a accomplished fact, that is the excuse of not being able to provided aerial security of our country is pathetic!

It is not a question of money, funds are available to repair the aircraft and replace 24/24 aviation safety in the sky of Switzerland. Mr. Maurer is guilty of mismanagement and influence peddling to achieve his obscure political designs.

Related links:

Cracks in the Swiss Air Force F-5E Tiger: http://orbiterchspacenews.blogspot.ch/2015/01/cracks-in-swiss-air-force-f-5e-tiger.html

It is not! The Gripen aircraft will not fly in Switzerland: http://orbiterchspacenews.blogspot.ch/2014/05/it-is-not-gripen-aircraft-will-not-fly.html

Images, Text, Credits: ATS/Swiss Air Force/Orbiter.ch Aerospace.

Greetings, Orbiter.ch

NASA’s Dawn Spacecraft Captures Best-Ever View of Dwarf Planet












ESA - Dawn Mission patch.

January 27, 2015

NASA’s Dawn spacecraft has returned the sharpest images ever seen of the dwarf planet Ceres. The images were taken 147,000 miles (237,000 kilometers) from Ceres on Jan. 25, and represent a new milestone for a spacecraft that soon will become the first human-made probe to visit a dwarf planet.

"We know so little about our vast solar system, but thanks to economical missions like Dawn, those mysteries are being solved," said Jim Green, Planetary Science Division Director at NASA Headquarters in Washington.

At 43 pixels wide, the new images are more than 30 percent higher in resolution than those taken by NASA's Hubble Space Telescope in 2003 and 2004 at a distance of over 150 million miles. The resolution is higher because Dawn is traveling through the solar system to Ceres, while Hubble remains fixed in Earth orbit. The new Dawn images come on the heels of initial navigation images taken Jan. 13 that reveal a white spot on the dwarf planet and the suggestion of craters. Hubble images also had glimpsed a white spot on the dwarf planet, but its nature is still unknown.


Image above: This animation of the dwarf planet Ceres was made by combining images taken by NASA's Dawn spacecraft on Jan. 25. The spacecraft's framing camera took these images, at a distance of about 147,000 miles (237,000 kilometers) from Ceres, and they represent the highest-resolution views to date of the dwarf planet. Image Credit: NASA/JPL.

"Ceres is a 'planet' that you've probably never heard of,” said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California. “We're excited to learn all about it with Dawn and share our discoveries with the world."

As the spacecraft gets closer to Ceres, its camera will return even better images. On March 6, Dawn will enter into orbit around Ceres to capture detailed images and measure variations in light reflected from Ceres, which should reveal the planet’s surface composition.

"We are already seeing areas and details on Ceres popping out that had not been seen before. For instance, there are several dark features in the southern hemisphere that might be craters within a region that is darker overall," said Carol Raymond, deputy principal investigator of the Dawn mission at JPL. "Data from this mission will revolutionize our understanding of this unique body. Ceres is showing us tantalizing features that are whetting our appetite for the detailed exploration to come."

Ceres, the largest body between Mars and Jupiter in the main asteroid belt, has a diameter of about 590 miles (950 kilometers). Some scientists believe the dwarf planet harbored a subsurface ocean in the past and liquid water may still be lurking under its icy mantle.

Originally described as a planet, Ceres was later categorized as an asteroid, and then reclassified as a dwarf planet in 2006. The mysterious world was discovered in 1801 by astronomer Giuseppe Piazzi, who named the object for the Roman goddess of agriculture, grain crops, fertility and motherly relationships.


Image above: Zoomed out -- PIA19173 Ceres appears sharper than ever at 43 pixels across, a higher resolution than images of Ceres taken by the NASA's Hubble Space Telescope in 2003 and 2004. Image Credit: NASA/JPL.

“You may not realize that the word ‘cereal’ comes from the name Ceres. Perhaps you already connected with the dwarf planet at breakfast today," said JPL's Marc Rayman, Mission Director and Chief Engineer of the Dawn mission.

Powered by a uniquely capable ion propulsion system, Dawn also orbited and explored Vesta, the second most massive body in the asteroid belt. From 2011 to 2012, Dawn returned more than 30,000 images, 18 million light measurements and other scientific data about the impressive large asteroid. Vesta has a diameter of about 326 miles (525 kilometers).

"With the help of Dawn and other missions, we are continually adding to our understanding of how the solar system began and how the planets were formed,” said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.

Dawn's mission to Vesta and Ceres 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 Sciences Corp. of Dulles, Virginia, designed and built the spacecraft. JPL is managed for NASA by the California Institute of Technology in Pasadena.

The framing cameras were provided by the Max Planck Institute for Solar System Research in Gottingen, Germany, with significant contributions by the German Aerospace Center (DLR) Institute of Planetary Research in Berlin, and in coordination with the Institute of Computer and Communication Network Engineering in Braunschweig.

The visible and infrared mapping spectrometer was provided by the Italian Space Agency and the Italian National Institute for Astrophysics, was built by Selex ES, and is managed by Italy’s National Institute for Astrophysics and Planetology in Rome. The gamma ray and neutron detector was built by Los Alamos National Laboratory in New Mexico, and is operated by the Planetary Science Institute of Tucson, Arizona.

The new Dawn images are available online at: http://go.nasa.gov/1wyp0LA

To view the images taken by Hubble, visit: http://go.nasa.gov/1Ju41mf

More information about Dawn is available online at: http://www.nasa.gov/dawn

Images (mentioned), Text, Credits: NASA/Dwayne Brown / Felicia Chou.

Cheers, Orbiter.ch

Citizen Scientists Lead Astronomers to Mystery Objects in Space












NASA - Spitzer Space Telescope patch.

January 27, 2015

Sometimes it takes a village to find new and unusual objects in space. Volunteers scanning tens of thousands of starry images from NASA's Spitzer Space Telescope, using the Web-based Milky Way Project, recently stumbled upon a new class of curiosities that had gone largely unrecognized before: yellow balls. The rounded features are not actually yellow -- they just appear that way in the infrared, color-assigned Spitzer images. 

"The volunteers started chatting about the yellow balls they kept seeing in the images of our galaxy, and this brought the features to our attention," said Grace Wolf-Chase of the Adler Planetarium in Chicago. A colorful, 122-foot (37-meter) Spitzer mosaic of the Milky Way hangs at the planetarium, showcasing our galaxy's bubbling brew of stars. The yellow balls in this mosaic appear small but are actually several hundred to thousands of times the size of our solar system.


Image above: Volunteers using the web-based Milky Way Project brought star-forming features nicknamed "yellowballs" to the attention of researchers, who later showed that they are a phase of massive star formation. Image Credit: NASA/JPL-Caltech.

"With prompting by the volunteers, we analyzed the yellow balls and figured out that they are a new way to detect the early stages of massive star formation," said Charles Kerton of Iowa State University, Ames. "The simple question of 'Hmm, what's that?' led us to this discovery." Kerton is lead author, and Wolf-Chase a co-author, of a new study on the findings in the Astrophysical Journal.

The Milky Way Project is one of many so-called citizen scientist projects making up the Zooniverse website, which relies on crowdsourcing to help process scientific data. So far, more than 70 scientific papers have resulted from volunteers using Zooniverse, four of which are tied to the Milky Way Project. In 2009, volunteers using a Zooniverse project called Galaxy Zoo began chatting about unusual objects they dubbed "green peas."  Their efforts led to the discovery of a class of compact galaxies that churned out extreme numbers of stars.

In the Milky Way Project, volunteers scan through images that Spitzer took of the thick plane of our galaxy, where newborn stars are igniting in swaths of dust. The infrared wavelengths detected by Spitzer have been assigned visible colors we can see with our eyes. In addition to the yellow balls, there are many green bubbles with red centers, populating a landscape of swirling gas and dust. These bubbles are the result of massive newborn stars blowing out cavities in their surroundings. The green bubble rims are made largely of organic molecules called polycyclic aromatic hydrocarbons (PAHs), cleared away by blasts of radiation and winds from the central star. Dust warmed by the star appears red in the center of the bubbles.

Volunteers have classified more than 5,000 of these green bubbles using the project's Web-based tools. When they started reporting that they were finding more reoccurring features in the shape of yellow balls, the Spitzer researchers took note and even named the features accordingly. In astronomy and other digital imaging, yellow represents areas where green and red overlap. So what are these yellow balls?


Image above: This series of images show three evolutionary phases of massive star formation, as pictured in infrared images from NASA's Spitzer Space Telescope. Image Credit: NASA/JPL-Caltech.

A thorough analysis by the team led to the conclusion that the yellow balls precede the green bubble features, representing a phase of star formation that takes place before the bubbles form.

"The yellow balls are a missing link," said Wolf-Chase, "between the very young embryonic stars buried in dark filaments and newborn stars blowing the bubbles."

"If you wind the clock backwards from the bubbles, you get the yellow ball features," said Kerton.

The researchers explained why the yellow balls appear yellow: The PAHs, which appear green in the Spitzer images, haven't been cleared away by the winds from massive stars yet, so the green overlaps with the warm dust, colored red, to make yellow. The yellow balls are compact because the harsh effects of the massive star have yet to fully expand into their surroundings.

So far, the volunteers have identified more than 900 of these compact yellow features. The next step for the researchers is to look at their distribution. Many appear to be lining the rims of the bubbles, a clue that perhaps the massive stars are triggering the birth of new stars as they blow the bubbles, a phenomenon known as triggered star formation. If the effect is real, the researchers should find that the yellow balls statistically appear more often with bubble walls.

"These results attest to the importance of citizen scientist programs," said Wolf-Chase. Kerton added, "There is always the potential for serendipitous discovery that makes citizen science both exciting for the participants and useful to the professional astronomer."

NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

Related links:

The Milky Way Project: http://www.milkywayproject.org/

The Zooniverse website: https://www.zooniverse.org/

For more information about Spitzer, visit: http://spitzer.caltech.edu
and http://www.nasa.gov/spitzer

Images (mentioned), Text, Credits: NASA/JPL/Whitney Clavin.

Greetings, Orbiter.ch

lundi 26 janvier 2015

Asteroid That Flew Past Earth Today Has Moon










Asteroid Watch logo.

January 26, 2015

Scientists working with NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone, California, have released the first radar images of asteroid 2004 BL86. The images show the asteroid, which made its closest approach today (Jan. 26, 2015) at 8:19 a.m. PST (11:19 a.m. EST) at a distance of about 745,000 miles (1.2 million kilometers, or 3.1 times the distance from Earth to the moon), has its own small moon.

The 20 individual images used in the movie were generated from data collected at Goldstone on Jan. 26, 2015. They show the primary body is approximately 1,100 feet (325 meters) across and has a small moon approximately 230 feet (70 meters) across. In the near-Earth population, about 16 percent of asteroids that are about 655 feet (200 meters) or larger are a binary (the primary asteroid with a smaller asteroid moon orbiting it) or even triple systems (two moons). The resolution on the radar images is 13 feet (4 meters) per pixel.

video
Asteroid 2004 BL86 Has a Small Moon

Video above: This movie of asteroid 2004 BL86 was generated from data collected by NASA's Deep Space Network antenna at Goldstone, California, on Jan. 26, 2015. Twenty individual images were used.

The trajectory of asteroid 2004 BL86 is well understood. Monday's flyby was the closest approach the asteroid will make to Earth for at least the next two centuries. It is also the closest a known asteroid this size will come to Earth until asteroid 1999 AN10 flies past our planet in 2027.

Asteroid 2004 BL86 was discovered on Jan. 30, 2004, by the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico.

Radar is a powerful technique for studying an asteroid's size, shape, rotation state, surface features and surface roughness, and for improving the calculation of asteroid orbits. Radar measurements of asteroid distances and velocities often enable computation of asteroid orbits much further into the future than if radar observations weren't available.

Asteroid 2004 BL86 on January 19, 2015

NASA places a high priority on tracking asteroids and protecting our home planet from them. In fact, the U.S. has the most robust and productive survey and detection program for discovering near-Earth objects (NEOs). To date, U.S. assets have discovered over 98 percent of the known NEOs.

In addition to the resources NASA puts into understanding asteroids, it also partners with other U.S. government agencies, university-based astronomers, and space science institutes across the country, often with grants, interagency transfers and other contracts from NASA, and also with international space agencies and institutions that are working to track and better understand these objects.

NASA's Near-Earth Object Program at NASA Headquarters, Washington, manages and funds the search, study and monitoring of asteroids and comets whose orbits periodically bring them close to Earth. JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


Image above: Artist's impression of asteroid 2004 BL86 passing close by Earth on the evening of 26th January.

In 2016, NASA will launch a robotic probe to one of the most potentially hazardous of the known NEOs. The OSIRIS-REx mission to asteroid (101955) Bennu will be a pathfinder for future spacecraft designed to perform reconnaissance on any newly discovered threatening objects. Aside from monitoring potential threats, the study of asteroids and comets enables a valuable opportunity to learn more about the origins of our solar system, the source of water on Earth, and even the origin of organic molecules that led to the development of life.

NASA's Goddard Space Flight Center in Greenbelt, Maryland, will provide overall mission management, systems engineering, and safety and mission assurance for OSIRIS-REx. Lockheed Martin Space Systems in Denver will build the spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency's Science Mission Directorate in Washington.

Goldstone Deep Space Communication Complex

NASA also continues to advance the journey to Mars through progress on the Asteroid Redirect Mission (ARM), which will test a number of new capabilities needed for future human expeditions to deep space, including to Mars. This includes advanced Solar Electric Propulsion -- an efficient way to move heavy cargo using solar power, which could help pre-position cargo for future human missions to the Red Planet. As part of ARM, a robotic spacecraft will rendezvous with a near-Earth asteroid and redirect an asteroid mass to a stable orbit around the moon. Astronauts will explore the asteroid mass in the 2020’s, helping test modern spaceflight capabilities like new spacesuits and sample return techniques. Astronauts at NASA's Johnson Space Center in Houston have already begun to practice the capabilities needed for the mission.

More information about asteroids and near-Earth objects is available at: http://neo.jpl.nasa.gov and http://www.jpl.nasa.gov/asteroidwatch

and via Twitter at http://www.twitter.com/asteroidwatch

More information about asteroid radar research is at: http://echo.jpl.nasa.gov/

More information about the Deep Space Network is at: http://deepspace.jpl.nasa.gov/dsn

For more information about the OSIRIS-REx mission, visit: http://www.nasa.gov/osiris-rex and http://osiris-rex.lpl.arizona.edu

Images, Video, Text, Credits: NASA/JPL/DC Agle/ESA/P. Carril.

Greetings, Orbiter.ch

Rosetta watches comet shed its dusty coat












ESA - Rosetta Mission patch.

26 January 2015

ESA's Rosetta mission is providing unique insight into the life cycle of a comet's dusty surface, watching 67P/Churyumov-Gerasimenko as it sheds the dusty coat it has accumulated over the past four years.


Image above: Fluffy dust grains. Credit: ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S.

The COmetary Secondary Ion Mass Analyser, or COSIMA, is one of Rosetta's three dust analysis experiments. It started collecting, imaging and measuring the composition of dust particles shortly after the spacecraft arrived at the comet in August 2014.

Results from the first analysis of its data are reported today in the journal Nature. The study covers August to October, when the comet moved along its orbit between about 535 million kilometres to 450 million kilometres from the Sun. Rosetta spent the most of this time orbiting the comet at distances of 30 km or less.

The scientists looked at the way that many large dust grains broke apart when they were collected on the instrument's target plate, typically at low speeds of 1-10 m/s. The grains, which were originally at least 0.05 mm across, fragmented or shattered upon collection.

The fact that they broke apart so easily means that the individual parts were not well bound together. Moreover, if they had contained ice, they would not have shattered. Instead, the icy component would have evaporated off the grain shortly after touching the collecting plate, leaving voids in what remained.

By comparison, if a pure water-ice grain had struck the detector, then only a dark patch would have been seen.


Image above: Comet 67P/C-G on 12 January 2015 - NavCam mosaic. Credit: ESA/Rosetta/NAVCAM, CC BY-SA IGO 3.0.

The dust particles were found to be rich in sodium, sharing the characteristics of 'interplanetary dust particles'. These are found in meteor streams originating from comets, including the annual Perseids from Comet 109P/Swift-Tuttle and the Leonids from 55P/Tempel-Tuttle.

"We found that the dust particles released first when the comet started to become active again are 'fluffy'. They don't contain ice, but they do contain a lot of sodium. We have found the parent material of interplanetary dust particles," says lead author Rita Schulz of ESA's Scientific Support Office.

The scientists believe that the grains detected were stranded on the comet's surface after its last perihelion passage, when the flow of gas away from the surface had subsided and was no longer sufficient to lift dust grains from the surface.

While the dust was confined to the surface, the gas continued evaporating at a very low level, coming from ever deeper below the surface during the years that the comet travelled furthest from the Sun. Effectively, the comet nucleus was 'drying out' on the surface and just below it.

"We believe that these 'fluffy' grains collected by Rosetta originated from the dusty layer built up on the comet's surface since its last close approach to the Sun," explains Martin Hilchenbach, COSIMA principal investigator at the Max-Planck Institute for Solar System research in Germany.

"This layer is being removed as the activity of the comet is increasing again. We see this layer being removed, and we expect it to evolve into a more ice-rich phase in the coming months."

The comet is on a 6.5-year circuit around the Sun, and is moving towards its closest approach in August of this year. At that point, Rosetta and the comet will be 186 million kilometres from the Sun, between the orbits of Earth and Mars.

As the comet warms, the outflow of gases is increasing and the grains making up the dry surface layers are being lifted into the inner atmosphere, or coma. Eventually, the incoming solar energy will be high enough to remove all of this old dust, leaving fresher material exposed at the surface.

"In fact, much of the comet's dust mantle should actually be lost by now, and we will soon be looking at grains with very different properties," says Rita.

"Rosetta's dust observations close to the comet nucleus are crucial in helping us to link together what is happening at the very small scale with what we see at much larger scales, as dust is lost into the comet's coma and tail," says Matt Taylor, ESA's Rosetta project scientist.

"For these observations, it really is a case of "watch this space" as we continue to watch in real time how the comet evolves as it approaches the Sun along its orbit over the coming months."

Notes for Editors:

"Comet 67P/Churyumov-Gerasimenko sheds dust coat accumulated over the past four years" by R. Schulz et al. is published in the 26 January issue of the journal Nature.

COSIMA was built by a consortium led by the Max-Planck-Institut für Extraterrestrische Physik (Garching, DE) in collaboration with Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, CNRS / Université d'Orléans (FR), Institut d'Astrophysique Spatiale, CNRS / Université Paris Sud (Orsay, FR), Finnish Meteorological Institute (Helsinki, FI), Universität Wuppertal (Wuppertal, DE), von Hoerner und Sulger GmbH (Schwetzingen, DE), Universität der Bundeswehr (Neubiberg, DE), Institut für Physik, Forschungszentrum Seibersdorf (Seibersdorf, AT), Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften (Graz, AT) and is led by the Max-Planck-Institut für Sonnensystemforschung (Göttingen, DE).

More about Rosetta:

Rosetta is an ESA mission with contributions from its Member States and NASA. Rosetta's Philae lander was provided by a consortium led by DLR, MPS, CNES and ASI. Rosetta is the first mission in history to rendezvous with a comet. It is escorting the comet as they orbit the Sun together. Philae landed on the comet on 12 November 2014. Comets are time capsules containing primitive material left over from the epoch when the Sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission should become the key to unlocking the history and evolution of our Solar System.

Related Publications:

Schulz, R., et al. (2015): http://sci.esa.int/rosetta/55343-schulz-et-al-2015/

Related link:

For more information about Rosetta mission, visit: http://www.esa.int/Our_Activities/Space_Science/Rosetta

Images (mentioned), Text, Credit: European Space Agency (ESA).

Best regards, Orbiter.ch

dimanche 25 janvier 2015

NASA Data Peers into Greenland’s Ice Sheet












NASA - Operation IceBridge patch.

January 25, 2015

A three-dimensional view of the age and structure of the Greenland Ice Sheet

Scientists using ice-penetrating radar data collected by NASA’s Operation IceBridge and earlier airborne campaigns have built the first-ever comprehensive map of layers deep inside the Greenland Ice Sheet.

video
Greenland's Ice Layers Mapped in 3D

Video above: Peering into the thousands of frozen layers inside Greenland’s ice sheet is like looking back in time. Each layer provides a record of what Earth’s climate was like at the dawn of civilization, or during the last ice age, or during an ancient period of warmth similar to the one we experience today. Image Credit: NASA Goddard's Scientific Visualization Studio.

This new map allows scientists to determine the age of large swaths of Greenland’s ice, extending ice core data for a better picture of the ice sheet’s history. “This new, huge data volume records how the ice sheet evolved and how it’s flowing today,” said Joe MacGregor, a glaciologist at The University of Texas at Austin’s Institute for Geophysics and the study’s lead author.

Greenland’s ice sheet is the second largest mass of ice on Earth, containing enough water to raise ocean levels by about 20 feet. The ice sheet has been losing mass over the past two decades and warming temperatures will mean more losses for Greenland. Scientists are studying ice from different climate periods in the past to better understand how the ice sheet might respond in the future.

One way of studying this distant past is with ice cores. These cylinders of ice drilled from the ice sheet hold evidence of past snow accumulation and temperature and contain impurities like dust and volcanic ash that were carried by snow that accumulated and compacted over hundreds of thousands of years. These layers are visible in ice cores and can be detected with ice-penetrating radar.

Ice-penetrating radar works by sending radar signals into the ice and recording the strength and return time of reflected signals. From those signals, scientists can detect the ice surface, sub-ice bedrock and layers within the ice.

New techniques used in this study allowed scientists to efficiently pick out these layers in radar data. Prior studies had mapped internal layers, but not at the scale made possible by these newer, faster methods. Another major factor in this study was the amount of Greenland IceBridge has measured.


Image above: An east Greenland glacier seen from the NASA P-3 in April 2014. Image Credit: NASA/Jim Yungel.

“IceBridge surveyed previously unexplored parts of the Greenland Ice Sheet and did it using state-of-the-art CReSIS radars,” said study co-author, Mark Fahnestock, a glaciologist from the Geophysical Institute at University of Alaska Fairbanks and IceBridge science team member. CReSIS is the Center for Remote Sensing of Ice Sheets, a National Science Foundation Science and Technology Center headquartered at the University of Kansas in Lawrence, Kansas. 

IceBridge’s flight lines often intersect ice core sites where other scientists have analyzed the ice’s chemical composition to map and date layers in the ice. These core data provide a reference for radar measurements and provide a way to calculate how much ice from a given climate period exists across the ice sheet, something known as an age volume. Scientists are interested in knowing more about ice from the Eemian period, a time from 115,000 to 130,000 years ago that was roughly as warm as today. This new age volume provides the first rough estimate of where Eemian ice may remain.

Comparing this age volume to simple computer models helped the study’s team better understand the ice sheet’s history. Differences in the mapped and modeled age volumes point to past changes in ice flow or processes like melting at the ice sheet’s base. This information will be helpful for evaluating the more sophisticated ice sheet models that are crucial for projecting Greenland’s future contribution to sea-level rise. “Prior to this study, a good ice-sheet model was one that got its present thickness and surface speed right. Now, they’ll also be able to work on getting its history right, which is important because ice sheets have very long memories,” said MacGregor.

This study was published online on Jan. 16, 2015, in Journal of Geophysical Research Earth Surface. It was a collaboration between scientists at UTIG, UAF-GI, CReSIS and the Dept. of Earth System Science at University of California, Irvine. It was supported by NASA’s Operation IceBridge and the National Science Foundation’s Arctic Natural Sciences.

Related link:

Journal of Geophysical Research Earth Surface: http://onlinelibrary.wiley.com/doi/10.1002/2014JF003215/abstract

For more information on Operation IceBridge, visit: http://www.nasa.gov/icebridge

Image (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center/George Hale.

Best regards, Orbiter.ch