vendredi 17 octobre 2014

Mars Express ready for comet encounter












ESA - Mars Express Mission patch.

17 October 2014

Europe’s Mars orbiter and its scientific instruments will have a frontrow seat on Sunday when Comet Siding Spring grazes the Red Planet, skimming past at a little more than a third of the Moon’s distance from Earth.

Comet Siding Spring, discovered in January 2013, is less than a kilometre across and will pass Mars at 56 km/s, closing to within 139 500 km at 18:27 GMT (20:27 CEST) on 19 October.

Initially, the comet and its envelope of gas and dust were predicted to pass much closer to Mars, posing a serious risk to the fleet of orbiting spacecraft. Later observations confirmed that the miss distance will, in fact, be more comfortable.

Mars and comet

ESA’s teams flying Mars Express have spent months preparing for the encounter.

“In 2013, we had very little information about the comet, which was still very far and faint. In the worst case, we expected the pass to be much closer, and the comet to be much more active,” says Spacecraft Operations Manager Michel Denis.

“We designed a special mode for Mars Express that would minimise any risk due to impacts with cometary particles.

“This included turning off all instruments and non-essential onboard systems, and turning the spacecraft so as to use the large high-gain antenna as a shield.”

Opportunity for unique science

Instead, Mars Express will operate substantially normally, and the close flyby will present an invaluable opportunity for science, including close-up observations of this enigmatic comet, the Mars atmosphere under the direct influence of the comet’s gas and dust, and the complex three-way interaction between Mars, the comet and the solar wind.

Mars Express

The detailed observation plans include high-resolution imaging of the comet and its structure.

“Most interestingly, we may also obtain images of cometary particles – meteors – burning up in the martian atmosphere, allowing an in-depth comparison of meteor science between Earth and Mars,” notes Håkan Svedhem, project scientist for Mars Express.

Oort Cloud object comes near

Siding Spring spent most of its life in the Oort Cloud, a shell surrounding our Sun some 5000–100 000 times the Earth–Sun distance and containing billions of comets thought to be left over from the formation of our Solar System.

“The best estimate of the maximum distance of Siding Spring is 60 000 times Earth’s distance from the Sun – almost exactly a light-year,” says Håkan.

“This makes it an extraordinary comet. It has most likely never been close to the Sun before.”

Mars Comet Science Workshop, Part III

Siding Spring will be the first Oort Cloud comet to be studied up close by spacecraft, giving scientists an invaluable opportunity to learn more about the materials, including water and carbon compounds, that existed during the formation of the Solar System 4.6 billion years ago.

Despite the much reduced risk of particle impacts on Mars Express, the control team will be watching closely on Sunday evening to ensure its safety.

Updates will be posted in the Mars Express blog and a webcast from ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany, will be streamed live 19 October, starting at 17:50 GMT (19:50 CEST).

Related links:

Mars Express blog: http://blogs.esa.int/mex

Webcast from ESA’s Space Operations Centre, ESOC: http://www.livestream.com/eurospaceagency

Mars Express overview: http://www.esa.int/Our_Activities/Space_Science/Mars_Express_overview

Mars Express in depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=9

Mars Express top 10 discoveries: http://sci.esa.int/jump.cfm?oid=51820

Images, Video, Text, Credits: ESA/R. Kaufman/Alex Lutkus/NASA.

Cheers, Orbiter.ch

Herschel's view of Comet Siding Spring












ESA - Herschel Mission patch.

17 October 2014

(Click on the image for enlarge)

Images above:
Date: 17 October 2014
Satellite: Herschel
Depicts: Comet Siding Spring (C/2013 A1)
Images Credits:: ESA/Herschel/PACS/Cs. Kiss et al. 2014

These three images show emission from the dust in the coma surrounding the nucleus of Comet C/2013 A1 – also known as Comet Siding Spring – as observed at three different far-infrared wavelengths with ESA's Herschel space observatory.

Discovered on 3 January 2013, Comet Siding Spring is an Oort Cloud comet on its first journey into the inner Solar System. It will reach perihelion – its closest approach to the Sun – on 25 October 2014 at 1.4 AU (about 210,000,000 km). Having spent most of its life far from the Sun, this comet is much more pristine than periodic comets – those that orbit the Sun every two hundred years or less – and for that reason is particularly interesting to study.

On 31 March 2013, not long after it was discovered, astronomers observed Comet Siding Spring with Herschel. This was just one month before the observatory exhausted its supply of liquid helium coolant and ceased to collect data. When Herschel observed it, the comet was about 6.5 AU from the Sun. The observations were performed following a proposal for Director’s Discretionary Time from Peter Mattisson from the Stockholm Amateur Astronomers (STAR) in Sweden.

The three panels show the comet at wavelengths of 70 microns (shown in blue), 100 microns (shown in green) and 160 microns (shown in red). Telescopes observing at these long wavelengths see the direct thermal emission from dust in the comet's coma.

The coma is resolved at the two shorter wavelengths (in the left and central panels). Close inspection of these two images reveals that the coma's shape is slightly elongated towards the left – in the direction opposite the Sun. From these images, astronomers estimated that the coma extends some 50,000 km from the comet's nucleus. The structure of the coma can hardly be resolved at the longest wavelength probed by Herschel (in the right panel).

These observations were also used to calculate the total mass of dust in the coma, which amounts to about 300,000,000 kg. At the time of the Herschel observations, the comet appeared to be quite active – astronomers estimated that the activity had begun even prior to the comet's discovery, when it was about 8 AU from the Sun. Observations performed at a later stage with space and ground-based telescopes showed that the comet's activity has increased quite slowly over the past months, which is quite unusual for an Oort Cloud comet. There are even some hints that the comet's activity has declined recently.

Herschel space observatory spacecraft. Image Credit: ESA

Astronomers have been closely monitoring the activity of Comet Siding Spring because, a few days before perihelion, the comet will have an historic close approach to Mars, passing some 140,000 km from the Red Planet on 19 October 2014. The comet's current moderate activity is good news for the fleet of spacecraft that are operated at Mars by various space agencies (including ESA's Mars Express) because it means a low risk of dust particles hitting the instruments on board.

Since Oort Cloud comets are discovered with an extremely short notice before perihelion – a few years at most – it is virtually impossible to plan a space mission to fly by such a comet. This is what makes Comet Siding Spring and its closest approach to Mars truly unique, as the spacecraft at Mars will have the chance to observe an Oort Cloud comet from a distance that could not possibly be achieved otherwise.

The analysis of the Herschel images was performed by Cs. Kiss (Konkoly Observatory, Budapest, Hungary), T.G. Müller (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), M. Kidger (ESAC, European Space Agency, Madrid, Spain), P. Mattisson (STAR, Stockholm Amateur Astronomers, Sweden), and G. Marton (Konkoly Observatory, Budapest, Hungary).

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

Images (mentioned), Text, Credit: ESA.

Greetings, Orbiter.ch

Cassini caught in Hyperion's electron beam












ESA - Cassini Missio to Saturn logo.

17 October 2014

Static electricity is known to play an important role on the airless, dusty Moon, but evidence of surface charging on other objects in the Solar System has been elusive. However, a new analysis of data from the international Cassini mission has revealed that the orbiter was briefly bathed in a beam of electrons coming from the electrostatically charged surface of Saturn's moon, Hyperion.

Hyperion is an irregular outer moon of Saturn, with a mean radius of 133 km. It has a low mean density, suggesting that it may consist primarily of water ice, with an unusually porous interior, resulting in a bizarre, sponge-like appearance.

Hyperion tumbles chaotically as it moves around Saturn at a distance of 1.48 million km – four times further than our Moon is from Earth. The distant, elliptical orbit often causes it to cross from the planet's magnetosphere - the invisible bubble generated by Saturn's internal magnetic dynamo – and enter the solar wind. This is partly due to its changing orbital position and partly due to expansion and contraction of the planet's magnetosphere.

As a result, Hyperion is sometimes exposed to plasma (charged particles – electrons and ions) trapped in the magnetosphere and sometimes it is bathed in the solar wind of particles ejected from the Sun. The surface of the airless satellite is also bombarded by solar ultraviolet (UV) light. This exposure to the hostile space environment causes some unusual effects.


Image above: Saturn's moon Hyperion. Credit: NASA/JPL/Space Science Institute.

Spacecraft observations and theoretical studies have previously shown that incoming solar radiation and charged particles can generate a static electrical charge on Earth's Moon. Now a team led by Tom Nordheim, a PhD student at Mullard Space Science Laboratory (MSSL), University College London, has shown that similar effects can occur on other small, airless objects, such as Hyperion. Their results are published in Geophysical Research Letters.

During a close encounter with Hyperion on 26 September 2005, unexpected measurements from several instruments on board the Cassini spacecraft indicated that something strange was taking place in the particle – plasma environment.

The new analysis of the data shows that Cassini was magnetically connected to the surface of Hyperion for a brief period, which enabled it to be bathed in a beam of electrons coming from the moon's surface.

"We know that objects in space, including Earth's Moon, may become electrostatically charged by exposure to solar ultraviolet light and incoming charged particles. This is comparable to what happens when you rub your hair against a balloon, or when a shirt or blouse rubs against a sweater," said Nordheim.

The Cassini data show that a similar process can take place on Hyperion. Due to its interaction with solar UV light and charged particles from Saturn's magnetosphere, the moon's surface may acquire a net electric charge. This is precisely what was found by Cassini's instruments.

Approximately 6 minutes before its closest approach to Hyperion, the Electron Spectrometer (ELS), part of the Cassini Plasma Spectrometer (CAPS) instrument, detected a sharp increase in the number of negatively charged particles. Cassini's magnetometer showed that these electrons were coming in a beam along the magnetic field lines, from the direction of Hyperion.

At the same time, the Radio and Plasma Wave instrument detected intense plasma wave fluctuations caused by the electron beam and the Magnetospheric Imaging Instrument observed the absorption of other particles by Hyperion.

Analysis of the CAPS-ELS data indicates that it remotely detected a strongly negative surface potential (-200 volts) on Hyperion, consistent with the predicted electrostatic charge in regions near the moon's terminator – the day-night boundary.

"The large difference in potential between the surface and the spacecraft resulted in a flow of electrons being accelerated from Hyperion toward Cassini," said Tom Nordheim. "It was rather like Cassini receiving a 200 volt electric shock from Hyperion, even though they were over 2000 km apart at the time."

"The alignment between the two was just right for us to be able to detect this fairly rare event. If Cassini had been in a different location during the flyby, the electron beam would not have been detected."


Image above: Hyperion shocks Cassini. Credit: UCL Mullard Space Science Laboratory/T. Nordheim, K. Eriksson, G. Jones; Hyperion image: NASA/JPL/Space Science Institute.

 The first confirmed detection of surface charging on an object in the outer Solar System has wide-ranging implications. This fundamental process is predicted to occur on many different bodies, including asteroids, moons and the surface of comets.

Scientists have previously suggested that surface features observed on the asteroid Eros and several Saturnian moons are due to the motion of charged dust across their surfaces. On small objects with low gravity, dust grains might even be able to overcome the force of gravity and escape into space.

In terms of human exploration of planetary objects without atmospheres, such as the Moon, strong electric charging effects may also prove to be a hazard to astronauts, who might be subjected to strong electrostatic discharges.

"Surface charging as a fundamental phenomenon affecting planetary objects is currently not well understood and while it has been observed on Earth's Moon, the Saturn system presents us with an opportunity to study this effect in an environment where many parameters are completely different," said Geraint Jones of MSSL, who co-supervised Tom Nordheim's research.

"Our observations show that this is also an important effect at outer planet moons and that we need to take this into account when studying how these moons interact with their environment."

"After 10 years in orbit around Saturn, Cassini continues to demonstrate its importance in probing the physics of the highly complex, interconnected system made up of the giant ringed planet, its moons and their immediate space environment," said Nicolas Altobelli, ESA's Cassini-Huygens Project Scientist.

"We see once again that the knowledge gained by this remarkable explorer can be applied to other places in the Solar System and beyond."

More Information:

Detection of a strongly negative surface potential at Saturn's moon Hyperion, by T. Nordheim et al., is published in Geophysical Research Letters, 2014; DOI: 10.1002/2014GL061127

The Cassini–Huygens mission is a cooperative project of NASA, ESA and the Italian Space Agency (ASI). Launched in 1997, Cassini arrived in the Saturn system in 2004 and is studying the ringed planet and its moons. The Huygens probe was released from the main spacecraft and, in 2005, parachuted through the atmosphere to the surface of Saturn's largest moon, Titan.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C.

Detection of a strongly negative surface potential at Saturn's moon Hyperion: http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=54780

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

Images (mentioned), Text, Credit: ESA.

Best regards, Orbiter.ch

jeudi 16 octobre 2014

A Different Kind of Green Movement: Seedling Growth in Space












ISS - Seedling Growth-2 mission patch.

October 16, 2014

Plants—literally rooted in Earth—lack locomotion. And although plants may appear static, even the tiniest seedlings are sophisticated organisms that sense and respond to their environment. Seedlings may not travel, but they do move.

An international team of NASA and European Space Agency (ESA) researchers are studying the growth and development of Arabidopsis thaliana seedlings – also known as "thale cress" – aboard the International Space Station to gain a better understanding of how plants adapt to weightless and low-gravity environments. Scientists appreciate Arabidopsis thaliana more for its small, fully sequenced genome than for what it may add to a salad. It is a widely studied biological research model.

The Seedling Growth-2 mission is the second in a series of NASA-ESA collaborative plant biology experiments using the European Modular Cultivation System (EMCS) facility aboard the space station. The investigation launched to the station aboard a SpaceX Falcon 9 rocket on Sept. 21, 2014. Station crew will start the first experimental run of the study on October 17.


Image above: Arabidopsis thaliana seeds are mounted in a specific orientation onto supportive membranes for the Seedling Growth-2 mission. Image Credit: NASA / Dominic Hart.

Plants are essential to support life on Earth; they provide food and recycle carbon dioxide into breathable oxygen. This latter ability may prove critical for astronauts who will undertake long-duration deep space missions. A better understanding of how spaceflight affects plants will help researchers determine if plants can provide a complete, sustainable, dependable and economical means to support humans in space.

Plants adjust their growth and behavior in response to changing environmental conditions such as light exposure, temperature and humidity. Like all life on Earth, plants evolved under the constant force of gravity. Plants sense gravity, and gravity influences plant growth. 

"We are studying the interaction between gravity and light in plant development. More specifically, we want to better understand the role of red light signaling in phototropism—the directed growth of plants in response to light," said John Z. Kiss, Ph.D., professor of biology at the University of Mississippi, and NASA's principal investigator for the Seedling Growth-2 investigation.

Plants sense and respond to different colors of light. A seedling growing beneath another plant detects that it is in the shade by sensing that certain colors of sunlight are missing; those colors of light are screened out as sunlight passes through the canopy of leaves above. As a survival response, the seedling grows sideways rather than straight up in an effort to get out of the shade and receive direct sunlight. This is one example of phototropism.

This also is an example of plant signaling. Cellular sensors in one part of the seedling detected light. Subsequently, a signal traveled to cells in other parts of the seedling. These cells responded to the signal and changed the seedling’s direction of growth.

In the Seedling Growth-2 study, Kiss is studying three genetic strains of Arabidopsis thaliana seeds. One is a wild type or "normal" strain. The other two have genetic mutations and lack certain red light sensors called phytochromes.


Image above: Tiny Arabidopsis thaliana seeds are visible as a dotted line across the membrane that is sealed inside of an experiment cassette. Image Credit: NASA / Dominic Hart.

"By studying the mutants and wild type seedlings, we can better understand the role of specific phytochromes in plant signaling in microgravity and in Earth's gravity," said Kiss. "In the long term, these studies will aid in growing plants on space missions as well as on developing better crop species on Earth."

Because light and gravity sensing are limiting factors for crop plant growth and development, understanding these factors may help researchers to develop ways to optimize light sensing in plants and improve crop production. The findings also may help researchers develop new ways to reduce environmental impacts and increase long-term sustainability of agricultural practices on Earth.

For each run of the experiment, crew aboard the space station will place the equipment inside the EMCS. A team in Norway will control the system remotely from ESA’s Norwegian User Support and Operations Centre.

During the Seedling Growth-2 study, Arabidopsis thaliana seeds will germinate and grow for six days into tiny seedlings. Images of the seedlings downlinked to Earth will reveal the behavior of the seedlings as they grow under varying conditions of gravity and light.

Molecular biological analysis of the seedlings will be done in the laboratory of ESA principal investigator F. Javier Medina of the Spanish National Research Council in Madrid. The analysis that Medina’s team will perform on the plant tissues will help researchers shed light on the cellular signaling mechanisms involved in plant movement and growth.


Image above: Hardware integration engineer Stephen Martin places experiment cassettes that contain Arabidopsis thaliana seeds into a unique Ames equipment assembly for Seedling Growth-2. The assembly’s hardware and electronics will support the study inside the EMCS facility aboard the space station. Image Credit: NASA / Dominic Hart.

As each experiment run completes, the station crew will freeze the seedlings and keep them in the Minus Eighty-Degree Laboratory Freezer for the International Space Station (MELFI). The crew then will transfer the seedlings into the SpaceX Dragon spacecraft for a return trip to Earth. The still-frozen seedlings will arrive at NASA’s Ames Research Center in Moffett Field, California, where a team of plant biologists will chemically treat the seedlings to stabilize the plant tissue for a room temperature shipment to Europe.

"This project serves as a fine example of cooperation within NASA as well a collaboration between NASA and ESA," said Kiss. "Medina and I jointly serve as principal investigators for the Seedling Growth series of spaceflight investigations. By combining our technical and scientific efforts, the potential science return from this project is much greater than if we were both to work singly with our respective space agencies."

video
Space Station Live: Seedling Growth-2 Experiment

While the Seedling Growth-2 mission is in progress, researchers also are preparing for the third part of this investigation—Seedling Growth-3—that is planned to launch to the station in 2015. Kiss expects these studies will yield comprehensive new knowledge about the cell cycle, light signaling and development of plants in space.

"This type of research is vital to enable future long-range space travel and cultivation of plants on Mars for the purpose of human life support," said Kiss.

Some of the most well-traveled seedlings in history are revealing fundamental information about how plants sense and respond to light and gravity, and whether they will be able to accompany us as we travel deeper into space.

Related links:

European Space Agency (ESA): http://www.esa.int/

Seedling Growth-2 mission: http://www.nasa.gov/mission_pages/station/research/experiments/755.html

European Modular Cultivation System (EMCS) facility: http://www.nasa.gov/mission_pages/station/research/experiments/345.html

Minus Eighty-Degree Laboratory Freezer for the International Space Station (MELFI): http://www.nasa.gov/mission_pages/station/research/experiments/MELFI.html

NASA’s Ames Research Center: http://www.nasa.gov/centers/ames/home/

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

Images (mentioned), Video, Text, Credits: NASA Ames Research Center / Space Biosciences Division / Gianine M. Figliozzi.

Best regards, Orbiter.ch

Saturn Moon May Hide a 'Fossil' Core or an Ocean












NASA - Cassini Mission to Saturn patch.

October 16, 2014

A new study focused on the interior of Saturn's icy moon Mimas suggests its cratered surface hides one of two intriguing possibilities: Either the moon's frozen core is shaped something like a football, or the satellite contains a liquid water ocean.

Researchers used numerous images of Mimas taken by NASA's Cassini mission to determine how much the moon wobbles as it orbits Saturn. They then evaluated several possible models for how its interior might be arranged, finding two possibilities that fit their data.The study is published in the Oct. 17 issue of the journal Science.


Image above: This mosaic of Saturn's moon Mimas was created from images taken by NASA's Cassini spacecraft during its closest flyby of the moon on Feb. 13, 2010. Image Credit: NASA/JPL-Caltech/Space Science Institute.

"The data suggest that something is not right, so to speak, inside Mimas," said Radwan Tajeddine, a Cassini research associate at Cornell University, Ithaca, New York, and lead author on the paper. "The amount of wobble we measured is double what was predicted."

Either possiblity for the interior of Mimas would be interesting, according to Tajeddine, as the moon's heavily cratered outward appearance does not suggest anything unusual lies beneath its surface. Because Mimas formed more than four billion years ago, scientists would expect its core to have relaxed into a more or less spherical shape by now. So if Mimas' core is oblong in shape, it likely represents a record of the moon's formation, frozen in time.

If Mimas possesses an ocean, it would join an exclusive club of "ocean worlds" that includes several moons of Jupiter and two other Saturn moons, Enceladus and Titan. A global ocean would be surprising, said Tajeddine, as the surface of Mimas does not display signs of geologic activity.

Like a lot of moons in the solar system, including our own, Mimas always shows essentially the same face to its parent planet. This is called a spin-orbit resonance, meaning the moon's rotation, or spin, is in sync with its orbit around Saturn. Like Earth's moon, Mimas takes the same amount of time to spin completely around on its axis as it takes to orbit its planet.

The orbit of Mimas is very slightly stretched out, forming an ellipse rather than a perfect circle. This slight deviation causes the point on Mimas' surface that faces Saturn to vary a bit over the course of an orbit -- an observer on Saturn would see Mimas wobble slightly during its orbit, causing small amounts of terrain over the limb to become visible. This effect is called libration, and Earth's moon does it as well.

"Observing libration can provide useful insights about what is going on inside a body," said Tajeddine. "In this case, it is telling us that this cratered little moon may be more complex than we thought."

Models developed by Tajeddine and co-authors from France and Belgium indicate that, if Mimas is hiding a liquid water ocean, it lies 15 to 20 miles (24 to 31 kilometers) beneath the moon's impact-battered surface. At 246 miles (396 kilometers) wide, Mimas is too small to have retained internal heat from its formation, so some other source of energy would be required to maintain an underground ocean. The researchers note that there is evidence that Mimas' current, elongated orbit could have been even more stretched out in the past, which might have created enough tidal heating to produce an ocean.

Although an ocean within Mimas would be a surprise, the authors found that the interior model they considered for an oblong core ought to give the moon a slightly different shape than what is observed. They suggest that other models could be developed to explain the moon's observed libration, and that further measurements by Cassini could help determine which model is most likely to be correct.

Cassini spacecraft. Image Credits: ESA

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The imaging team is based at the Space Science Institute in Boulder, Colorado.

More information about Cassini is available at the following sites: http://www.nasa.gov/cassini and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

http://saturn.jpl.nasa.gov

Images (mentioned), Text, Credits: NASA / JPL / Preston Dyches.

Greetings, Orbiter.ch

Opportunity Rover Gets Panorama Image at 'Wdowiak Ridge'











NASA - Mars Exploration Rover B (MER-B) "Opportunity" patch.

October 16, 2014


Image above: This vista from NASA's Mars Exploration Rover Opportunity shows "Wdowiak Ridge," from left foreground to center, as part of a northward look with the rover's tracks visible at right. Opportunity's panoramic camera (Pancam) recorded the component images for this mosaic on Sept. 17, 2014. Image Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

The latest fieldwork site for NASA's Mars Exploration Rover Opportunity, which has been examining a series of Martian craters since 2004, is on the slope of a prominent hill jutting out of the rim of a large crater and bearing its own much smaller crater. It's called "Wdowiak Ridge."

"Wdowiak Ridge sticks out like a sore thumb.  We want to understand why this ridge is located off the primary rim of Endeavour Crater and how it fits into the geologic story of this region," said Opportunity science-team member Jim Rice of the Planetary Science Institute, Tucson, Arizona.

The ridge extends about 500 feet (about 150 meters) long and stands about 40 feet (12 meters) above surrounding ground, about two football fields' distance outside the main crest line of Endeavour Crater's western rim.


Image above: This stereo vista from NASA's Mars Rover Opportunity shows "Wdowiak Ridge," from left foreground to center, as part of a northward look. The image combines Sept. 17, 2014, views from the left eye and right eye of Opportunity's Pancam to appear three-dimensional when seen through blue-red glasses. Image Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

The science team calls it "Wdowiak Ridge" [DOW-ee-ak] as a tribute to former team member Thomas J. Wdowiak (1939-2013), who taught astronomy for decades at the University of Alabama, Birmingham.

A new vista from Opportunity's panoramic camera (Pancam) looks northward from near the southern end of Wdowiak Ridge and shows the hill with the rover's tracks along its base, at: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18614

"Tom would have enjoyed this view," said Rice, who first knew of Wdowiak as the enthusiastic outer-space expert who appeared on local television when Rice was a grade-schooler in Alabama in the 1960s.

"Decades later, when I was selected by NASA to be on the Mars rover science team with him, I told Tom I was one of the kids he inspired," Rice said. "Inspiring young people to become interested in space exploration is important to us on this mission."


Image above: This north-looking vista from NASA's Mars Rover Opportunity shows "Wdowiak Ridge," from left foreground to center. This version is presented in false color, which enhances visibility of the rover's wheel tracks at right. It combines multiple images taken by Opportunity's Pancam on Sept. 17, 2014. Image Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

Opportunity approached Wdowiak Ridge from the north on the rover's traverse along the western rim of Endeavour crater, which is about 14 miles (22 kilometers) in diameter. The rover is now examining rocks that were tossed outward by an impact that dug a crater 100 feet wide (30 meters) into the southern end of the ridge. That much-smaller crater is called "Ulysses."

"Ulysses is punched down into Wdowiak Ridge, so this boulder field around the crater gives us samples of different types of rocks from inside the ridge," said Opportunity Principal Investigator Steve Squyres, of Cornell University, Ithaca, New York. "Wdowiak Ridge is one on the most dramatic topographic features we've seen on this mission. Why does it stand up the way it does?  Is it especially resistant to erosion? What formed it?"

Mars Exploration Rover B (MER-B) "Opportunity". Image Credits: NASA/JPL-Caltech

During Opportunity's first decade on Mars and the 2004-2010 career of its twin, Spirit, NASA's Mars Exploration Rover Project yielded a range of findings proving wet environmental conditions on ancient Mars -- some very acidic, others milder and more conducive to supporting life.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for NASA's Science Mission Directorate in Washington. For more information about Spirit and Opportunity, visit: http://www.nasa.gov/rovers and http://marsrovers.jpl.nasa.gov

You can follow the project on Twitter and on Facebook at: http://twitter.com/MarsRovers and http://www.facebook.com/mars.rovers

Images (mentioned), Text, Credits: NASA / JPL / Guy Webster.

Cheers, Orbiter.ch

Arianespace successfully launches two satellites for the Americas


















ARIANESPACE - Flight VA220 Mission poster.


October 16, 2014

Ariane 5 ECA rocket launch Intelsat 30 & ARSAT-1 satellites

Arianespace has successfully launched two telecommunications satellites:   Intelsat 30, which is hosting the DLA-1 Ku-band payload for DIRECTV Latin America, is designed to provide distribution services for DIRECTV Latin America in South America and the Caribbean and ARSAT-1, which features direct-to-home (DTH) TV broadcast payloads for Latin America. The launch was performed by an Ariane 5 ECA on October 16 at 6:43 pm (local time) from the Guiana Space Center in Kourou, French Guiana. This launch again clearly shows that Arianespace's quality, reliability and experience are recognized by all operators, established and new, global and regional.

video
Arianespace delivers for Latin America! Ariane 5 orbits Intelsat 30 and ARSAT-1

Arianespace, the benchmark launch services provider for all operators, established or new

Intelsat 30 is a 20-kilowatt class Ku-and C-band satellite.  The Ku-band payload, known as DLA-1, is designed to provide distribution services for DIRECTV Latin America in South America and the Caribbean. The C-band portion enhances Intelsat’s existing C-band service infrastructure serving Latin America. This is the 54th satellite launched by Arianespace for Intelsat and the sixth for DIRECTV, as well as the 45th satellite built by Space Systems/Loral (SSL) to be orbited by Arianespace. Today's launch clearly shows the relationship of mutual trust established by Arianespace, Intelsat and Space Systems/Loral over the last 31 years.

ARSAT-1 is the first in a series of three geostationary (GEO) satellites that will give Argentina its own space telecommunications system. It is the first satellite of this type to be built in Argentina, by the state-owned company Invap in its plant in Bariloche, north of Patagonia. It is also the first part of the space infrastructure being built by Arsat, for which Arianespace's experience and reliable launch solutions played a decisive role in this successful market entry.

ARSAT-1 satellite

Arianespace and Latin America

With this launch, Arianespace is sharing its expertise with two customers that have very different requirements, although both are based in the Americas. Intelsat is a global operator and world leader in fixed satellite services (FSS) that has been operating in Latin America since 1965; while Arsat is a regional operator and is starting with this first satellite.

Intelsat 30/DLA satellite

Arianespace has launched nearly three-fourths of all commercial satellites for operators in Latin America, where demand for access to space is growing.

Arianespace, global leader in commercial GTO launches, with nearly 60% of the market

Having launched 60% of commercial satellites now in orbit, Arianespace clearly sets the standard for all satellite manufacturers and operators. This year to date, Arianespace has orbited seven out of the 12 geostationary commercial satellites launched.

Shortly after the announcement that the satellites had been injected into orbit, Arianespace Chairman and CEO Stéphane Israël said: "Arianespace is very proud of being able to share our expertise with customers in the Americas. Whether for Intelsat, our first commercial customer and the worldwide leader in fixed satellite services, or Arsat, a new regional operator in South America – to whom we with a long, successful life – Arianespace provides tailored launch services with proven quality and reliability. I would like to thank Intelsat for their continued loyalty throughout our 31 year partnership, which honors us, and also thank Arsat and Argentina for placing their trust in us for the launch of their first satellite, which is so important for the company and for the country as a whole. I would also like to thank DIRECTV, for whom the Intelsat 30 payload was custom-built, with whom we have a number of projects now under way. Lastly, thanks to everybody who contributed to this latest success: our prime Airbus and its European partners for the Ariane 5 ECA launcher, with its unrivaled reliability; our partners CNES-CSG and all staff at the launch base for the record availability achieved since the beginning of the year". 

For more information about Arianespace, visit: http://www.arianespace.com/index/index.asp

Images, Video, Text, Credits: Arianespace / Gunter Space Page / Orbiter.ch Aerospace.

Greetings, Orbiter.ch

Hubble Finds Extremely Distant Galaxy through Cosmic Magnifying Glass











NASA - Hubble Space Telescope patch.

October 16, 2014


Image above: The mammoth galaxy cluster Abell 2744 is so massive that its powerful gravity bends the light from galaxies far behind it, making these otherwise unseen background objects appear larger and brighter than they would normally. Image Credit: NASA, J. Lotz, (STScI).

Peering through a giant cosmic magnifying glass, NASA’s Hubble Space Telescope has spotted a tiny, faint galaxy -- one of the farthest galaxies ever seen. The diminutive object is estimated to be more than 13 billion light-years away.

This galaxy offers a peek back to the very early formative years of the universe and may just be the tip of the iceberg.

“This galaxy is an example of what is suspected to be an abundant, underlying population of extremely small, faint objects that existed about 500 million years after the big bang, the beginning of the universe,” explained study leader Adi Zitrin of the California Institute of Technology in Pasadena, California. “The discovery is telling us galaxies as faint as this one exist, and we should continue looking for them and even fainter objects, so that we can understand how galaxies and the universe have evolved over time.”

The galaxy was detected by the Frontier Fields program, an ambitious three-year effort that teams Hubble with NASA’s other great observatories -- the Spitzer Space Telescope and Chandra X-ray Observatory -- to probe the early universe by studying large galaxy clusters. These clusters are so massive their gravity deflects light passing through them, magnifying, brightening, and distorting background objects in a phenomenon called gravitational lensing. These powerful lenses allow astronomers to find many dim, distant structures that otherwise might be too faint to see.

The discovery was made using the lensing power of the mammoth galaxy cluster Abell 2744, nicknamed Pandora’s Cluster, which produced three magnified images of the same, faint galaxy. Each magnified image makes the galaxy appear 10 times larger and brighter than it would look without the zooming qualities of the cluster.

The galaxy measures merely 850 light-years across -- 500 times smaller than our Milky Way galaxy-- and is estimated to have a mass of only 40 million suns. The Milky Way, in comparison, has a stellar mass of a few hundred billion suns. And the galaxy forms about one star every three years, whereas the Milky Way galaxy forms roughly one star per year. However, given its small size and low mass, Zitrin said the tiny galaxy actually is rapidly evolving and efficiently forming stars.

The astronomers believe galaxies such as this one are probably small clumps of matter that started to form stars and shine, but do not yet have a defined structure. It is possible Hubble is only detecting one bright clump magnified due to the lensing. This would explain why the object is smaller than typical field galaxies of that time.

Zitrin’s team spotted the galaxy’s gravitationally multiplied images using near-infrared and visible-light photos of the galaxy cluster taken by Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys. But they needed to measure how far away it was from Earth.

Usually, astronomers can determine an object’s distance based on how far its light has been stretched as the universe slowly expands. Astronomers can precisely measure this effect through spectroscopy, which characterizes an object’s light. But the gravitationally-lensed galaxy and other objects found at this early time period are too far away and too dim for spectroscopy, so astronomers use an object’s color to estimate its distance. The universe’s expansion reddens an object’s color in predictable ways, which scientists can measure.

Zitrin’s team performed the color-analysis technique and took advantage of the multiple images produced by the gravitational lens to independently confirm the group’s distance estimate. The astronomers measured the angular separation between the three magnified images of the galaxy in the Hubble photos. The greater the angular separation due to lensing, the farther away the object is from Earth.

To test this concept, the astronomers compared the three magnified images with the locations of several other closer, multiply-imaged background objects captured in Hubble images of Pandora’s cluster. The angular distance between the magnified images of the closer galaxies was smaller.

“These measurements imply that, given the large angular separation between the three images of our background galaxy, the object must lie very far away,” Zitrin explained. “It also matches the distance estimate we calculated, based on the color-analysis technique. So we are about 95 percent confident this object is at a remote distance, at redshift 10, a measure of the stretching of space since the big bang. The lensing takes away any doubt that this might be a heavily reddened, nearby object masquerading as a far more distant object.”

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Hubble orbiting Earth

Astronomers have long debated whether such early galaxies could have provided enough radiation to warm the hydrogen that cooled soon after the big bang. This process, called reionization, is thought to have occurred 200 million to 1 billion years after the birth of the universe. Reionization made the universe transparent to light, allowing astronomers to look far back into time without running into a “fog” of cold hydrogen.

The team’s results appeared in the September online edition of The Astrophysical Journal Letters.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.

For images and more information about Hubble, visit: http://www.nasa.gov/hubble and http://www.spacetelescope.org/

Image (mentioned), Video, Text, Credits: NASA / Felicia Chou / ESA.

Greetings, Orbiter.ch

NASA's IRIS Helps Explain Mysterious Heating of the Solar Atmosphere










NASA - IRIS Mission patch.

October 16, 2014


Image above: NASA’s Solar Dynamics Observatory provided the outer image of a coronal mass ejection on May 9, 2014. The IRIS spacecraft. The IRIS mission views the interface region that lies between the sun’s photosphere and corona in unprecedented detail for researchers to study. Image Credit: NASA, Lockheed Martin Solar & Astrophysics Laboratory.

NASA's newest sun-watcher, the Interface Region Imaging Spectrograph, launched in 2013 with a specific goal: track how energy and heat coursed through a little understood region of the sun called the interface region. Sandwiched between the solar surface and its outer atmosphere, the corona, the interface region is where the cooler temperatures of the sun's surface transition to the hotter temperatures above. Moreover, all the energy to power the sun's output -- including eruptions such as solar flares and the sun's constant outflow of particles called the solar wind -- must make its way through this region.


Image above: An artist's rendition of NASA's Interface Region Imaging Spectrograph, or IRIS, mission in space. Image Credit: NASA/Goddard Space Flight Center.

Five papers based on IRIS data will highlight different aspects of the energy’s journey from the sun’s surface through its atmosphere in the Oct. 17, 2014, issue of Science magazine. By looking at various regions of the interface region in unprecedented resolution, the papers offer clues to what heats the corona to unexplained temperatures of millions of degrees, far hotter than the surface of the sun itself, as well as what causes great writhing movement and accelerated particles throughout the solar atmosphere.

"This set of research really delivers on the promise of IRIS, which has been looking at a region of the sun with a level of detail that has never been done before," said Bart De Pontieu the IRIS science lead at Lockheed Martin in Palo Alto, California. "The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises."

Solar Heat Bombs

One of the biggest surprises comes in the form of heat pockets of 200,000 F, low in the solar atmosphere – far lower down than where such high temperatures were expected. In a paper led by Hardi Peter of the Max Planck Institute for Solar System Research in Gottingen, Germany, the pockets were named bombs because of how much energy they release in such a short time.

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IRIS Sees Solar Heat Bombs

Video above: Bright lights in this movie from NASA’s IRIS, represents spots of intense heat — at 200,000 F — that may hold clues to what heats the solar atmosphere to mysteriously high temperatures. Video Credit: NASA/IRIS/Peter.

Identifying different temperature material in the solar atmosphere is fairly straightforward, but it is much more complex to determine how high above the surface such material lies. Spotting such features relied heavily on IRIS' high-resolution spectrograph, an instrument that divides incoming light into its separate wavelengths. Such spectra can then be analyzed to see what temperature material is present in a given area as well as how dense it is and how fast it is moving. IRIS showed this very hot material sandwiched between two cold layers at temperatures usually found only near the sun's surface, thus giving information about its low-lying location that would have been otherwise hard to find.

"These unexpected results will likely lead to a reassessment of other phenomena in the low solar atmosphere," said Alan Title, the IRIS principal investigator at Lockheed.

Resolving Unresolved Structure

A second paper highlights IRIS' ability to zoom into part of the interface region, called the transition region, with unprecedented resolution. Early observations of the atmosphere hovering over the sun's limb from Skylab in the 1970s pointed to the fact that this layer must be more complicated and structured than what could be seen in those images – the energy emissions coming from the region just didn't seem to be physically possible based on the structure seen. But, like someone with nearsighted vision, Skylab didn't have the necessary resolution to determine exactly what that structure was.

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IRIS Resolving Unresolved Structure

Video above: NASA’s IRIS, which is able to look at a low layer of the sun’s atmosphere in unprecedented resolution, reveals details in the bright loops seen over the sun’s limb that have never been witnessed before. Video Credit: NASA/IRIS/Hansteen.

Able to see hundreds of times more detail than Skylab, IRIS has resolved numerous, small, low lying loops of material in the transition region, as described in a paper led by Viggo Hansteen, a solar scientist at the University of Oslo in Norway. These move quickly and last for only minutes at a time. At just a couple thousand miles high, the loops could not be seen with any previous instrument. Identifying such loops offers new insight into how the transition region emits the light and energy that we see: These loops show us a dynamic region where much heating occurs and is quickly released.

Mini-Tornadoes

A third paper uses IRIS to determine speeds of structures in the other part of the interface region just above the sun’s surface, called the chromosphere. The solar features seem to be twisting – one side of the loop appears to be moving away from the viewer, the other side is moving toward it.

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IRIS Reveals Speed of Solar Material, Sees Mini-Tornadoes

Video above: This movie shows succeeding images from NASA’s IRIS of the same area of the sun in different wavelengths. Each image carries information about how fast the solar material is moving, which has shown scientists that a series of loops are twisting in the sun’s lower atmosphere. Video Credit: NASA/IRIS/De Pontieu, Pereira.

"We conclude that the gas in the chromosphere is often twisting like a tornado twirling around a central magnetic tube," said De Pontieu, who is also the first author on this paper. "These twisting motions are often associated with heating to hundreds of thousands of degrees."

While fairly small by solar standards, these mini-tornadoes twist at up to 12 miles per second, and are scattered throughout the chromosphere. The tornadoes are signatures of a magnetic feature called Alfven waves, which are known to be able to carry energy and heat throughout the solar material.

High Speed Jets

A fourth paper led by Hui Tian at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, reveals insight about the very creation of the solar wind. It has generally been thought that the solar wind originates in a gentle way, evaporating from funnels of solar material that are rooted in strong magnetic field regions called networks on the sun's surface. However, these ideas might need to be updated based on IRIS observations of high-speed jets, traveling at speeds of 90 miles per second -- faster than any previously reported jet structures in the interface region.

The IRIS observations show such intermittent jets coming out of areas of weaker magnetic fields and less dense material in the solar atmosphere, called coronal holes, which are typically thought to be a source of the solar wind. Scientists' next steps are to determine whether the jets are indeed the origins of the solar wind – in contrast to previous predictions that the solar wind traveled through the interface region at just a couple miles per second – or at least how it relates to the solar wind.

Additionally, the jets show temperatures of 200,000 F and can be many times taller than the relatively thin transition region itself, which is about 300 miles high. Hui states that the jets appear to be one of the most important basic structures in the transition region – knowing more about them could help explain why the amount of energy emitted from the transition region is brighter than models would predict.

Accelerated Electrons in Nanoflares

The final paper spotted the effects of ubiquitous nanoflares throughout the corona. Large solar flares are initiated by a mechanism called magnetic reconnection, during which magnetic field lines cross and explosively realign, often sending particles zooming off at near-light speeds. Nanoflares are smaller versions of these that have long been hypothesized to drive coronal heating as they might release enough energy sufficient to heat the entire corona. In this paper, Paola Testa, also at the Harvard-Smithsonian Center for Astrophysics, used IRIS' ability to measure velocity to determine how the material at the footpoints of magnetic loops react to the accelerated particles that slam down into the interface region.

"Nanoflares have long been associated with coronal heating," said Title. "With this research we can show the properties of these high energy electrons and how they affect the interface region – the area where the bulk of solar atmospheric heating is known to occur."

This research has applications beyond just understanding the sun: These high-speed electrons also occur in other stars. Understanding what accelerates them on the sun can translate to better understanding of a host of astrophysical events.

"These five papers show clearly what IRIS offers to our studies of the sun," said Adrian Daw, the mission scientist for IRIS at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "We've never before been able to look at this low level of the atmosphere with such detail. Now, IRIS is uncovering a trove of information on how material moves and heats up there. "

This trove of new IRIS results has revealed a region of the sun more complicated than thought. Instead of homogenous layers of material of one temperature, the interface region is rife with heated zones threading and twisting through it. Together, this information will help scientists map the dynamic interface region for the first time to improve our understanding of how the vast deposits of magnetic energy and twisting solar material of the solar surface are transferred into the million degree temperatures above.

Goddard manages the Explorer Program for NASA's Science Mission Directorate in Washington. Lockheed Martin Solar & Astrophysics Laboratory designed the IRIS observatory and manages the mission for NASA. The Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., built the telescope. Montana State University in Bozeman designed the spectrograph. NASA's Ames Research Center in Moffett Field, California, provides mission operations and ground data systems. The Norwegian Space Centre is providing regular downlinks of science data. Other contributors include the University of Oslo and Stanford University in Stanford, California.

Related Links:

Download high resolution videos: http://svs.gsfc.nasa.gov/cgi-bin/details.cgi?aid=11708

For more information about IRIS, visit: http://www.nasa.gov/iris

Images (mentioned), Videos (mentioned), Text, Credits: NASA's Goddard Space Flight Center / Karen C. Fox.

Best regards, Orbiter.ch

Fishbone forest












ESA - Proba-V Mission logo.

October 16, 2014

Proba-V image of western Brazil

Deforestation in the state of Rondônia in western Brazil, as imaged by ESA’s Proba-V minisatellite.

This 300 m-resolution image reveals the human impact on the world’s largest tropical rainforest. The brownish colours indicate deforested areas – note the distinctive ‘fishbone’ pattern as main roads are cut through an area, followed by secondary roads for further clearing.

INPE, the Brazilian Institute for Space Research, uses satellites to monitor Brazil’s rainforests. Its results show the annual rate of deforestation has fallen from some 3900 sq km in 2004 to 900 sq km in 2013, although substantial amounts of precious forest are still disappearing every day.

Proba-V is a miniaturised ESA satellite tasked with a full-scale mission: to map land cover and vegetation growth across the entire planet every two days.

The camera’s continent-spanning field of view collects light in the blue, red, near-infrared and mid-infrared wavebands, ideal for monitoring plant and forest growth as well as inland water bodies.

Artist's view of the Proba-V satellite

Proba-V’s images are processed and distributed to hundreds of scientific users by VITO, Belgium’s Flemish Institute for Technological Research, extending the coverage of previous generations of the Vegetation camera flown on the Spot-4 and Spot-5 satellites.

For more information about Proba-V mission, visit: http://www.esa.int/Our_Activities/Technology/Proba_Missions

Images, Text, Credits. ESA / VITO.

Greetings, Orbiter.ch

mercredi 15 octobre 2014

ISRO PSLV rocket launch IRNSS-1C navigation satellite in orbit











ISRO - Indian Space Research Organisation logo.


October 15, 2014

 Launch of Indian IRNSS-1C GPS Satellite on PSLV Rocket from Satish Dhawan Space Centre

An Indian PSLV rocket successfully launched this evening at 20:02 UTC from the Satish Dhawan Space Centre carrying the IRNSS-1C satellite into orbit. IRNSS (Indian Regional Navigation Satellite System)-1C is the third of seven satellites planned that will provide positioning data for India under the complete control of Indian government due to the fact the American GPS system may not be guaranteed in hostile situations to foreign users.

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Launch of Indian IRNSS-1C GPS Satellite on PSLV Rocket

The first satellite, IRNSS-1A, was launched last July with the seven-satellite constellation scheduled for completion by the end of 2015.

IRNSS-1C is the first geostationary satellite in the IRNSS system. Planned for operation at a longitude of 83 degrees East, it will operate at the middle station of the constellation.

 IRNSS-1C navigation satellite

Two satellites already in orbit were deployed in July 2013 and April 2014, both riding PSLV rockets to orbit from the Satish Dhawan Space Centre. The PSLV, or Polar Satellite Launch Vehicle, is the same rocket which will be used to launch IRNSS-1C.

For more information about Indian Space Research Organisation (ISRO), visit: http://www.isro.org/

Images, Video, Text, Credits: ISRO / Orbiter.ch Aerospace.

Greetings, Orbiter.ch

Slow-Growing Galaxies Offer Window to Early Universe













NASA - Spitzer Space Telescope patch / ESA - Herschel Mission patch / NASA - GALEX Mission patch.

October 15, 2014

What makes one rose bush blossom with flowers, while another remains barren? Astronomers ask a similar question of galaxies, wondering how some flourish with star formation and others barely bloom.

A new study published in the Oct. 16 issue of the journal Nature addresses this question by making some of the most accurate measurements yet of the meager rates at which small, sluggish galaxies create stars. The report uses data from the European Space Agency's Herschel mission, in which NASA is a partner, and NASA's Spitzer Space Telescope and Galaxy Evolution Explorer (GALEX).

The findings are helping researchers figure out how the very first stars in our universe sprouted. Like the stars examined in the new study, the first-ever stars from billions of years ago took root in poor conditions. Growing stars in the early cosmos is like trying to germinate flower seeds in a bed of dry, poor soil. Back then, the universe hadn't had time yet to make "heavy metals," elements heavier than hydrogen and helium.


Image above: A small galaxy, called Sextans A. Image Credit: ESA/NASA/JPL-Caltech/NRAO.

"The metals in space help act in some ways like a fertilizer to help stars grow," said George Helou, an author of the new study and director of NASA's Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology, Pasadena. The lead author of the study is Yong Shi, who performed some of the research at IPAC before moving to Nanjing University in China.

The two slow-going galaxies in the study, called Sextans A and ESO 146-G14, lack in heavy metals, just like our young and remote cosmos, only they are a lot closer to us and easier to see.  Sextans A is located about 4.5 million light-years from Earth, and ESO 146-G14 is more than 70,000 light-years away.

These smaller galaxies are late bloomers. They managed to travel through history while remaining pristine, and never bulked up in heavy metals (heavy metals not only help stars to form, but are also created themselves by stars).

"The metal-poor galaxies are like islands left over from the early universe," said Helou. "Because they are relatively close to us, they are especially valuable windows to the past."

Studying star formation in poor growing environments such as these is tricky. The galaxies, though nearby, are still faint and hard to see. Shi and his international team wrangled the problem with a multi-wavelength approach. The Herschel data, captured at the longest infrared wavelengths of light, let the researchers see the cool dust in which stars are buried. The dust serves as a proxy for the total amount of gas in the region -- the basic ingredient of stars. To other telescopes, this dust is cold and invisible. Herschel, on the other hand, can pick up its feeble glow.

Herschel Space Observatory. Image Credit: ESA

Supporting radio-wavelength measurements of some of the gas in the galaxies came from the National Radio Astronomy Observatory's Jansky Very Large Array observatory near Socorro, New Mexico, and the Australia Telescope Compact Array observatory, near Narrabri.

Meanwhile, archived data from Spitzer and GALEX were used to look at the rate of star formation. Spitzer sees shorter-wavelength infrared light, which comes from dust that is warmed by new stars. GALEX images capture ultraviolet light from the shining stars themselves.

GALEX spacecraft. Image Credit: NASA

Putting all these pieces together enabled the astronomers to determine that the galaxies are plodding along, creating stars at rates 10 times lower than their normal counterparts.

"Star formation is very inefficient in these environments," said Shi. "Extremely metal-poor nearby galaxies are the best way to know what went on billions of years ago."

The heavy metals in present-day galaxies help star formation to flourish through cooling effects. For a star to form, a ball of gas needs to fall in on itself with the help of its own gravity. Ultimately, the material has to become dense enough for atoms to fuse and ignite, creating starlight. But as this cloud collapses, it heats up and puffs back out again, counteracting the process. Heavy metals cool everything down by radiating away the heat, enabling the cloud to condense into a star.

Spitzer Space Telescope. Image Credit: NASA

How stars in the early universe were able to do this without the cooling benefits of heavy metals remains unknown.

Studies like this shine light on the very first stellar buds, giving us a glimpse into the roots of our cosmic history.

NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. The GALEX mission, which ended in 2013, was also managed by JPL for NASA and led by Caltech. JPL served as the NASA Herschel Project Office for the European Space Agency's Herschel mission, which also ended in 2013.

Data from Spitzer and Herschel are accessible through the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

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

For more information about Spitzer mission, visit: http://www.spitzer.caltech.edu/

For more information about GALEX mission, visit: http://www.galex.caltech.edu/

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

Greetings, Orbiter.ch