Astronomen haben im frühen Universum eine neue Art von Galaxie entdeckt, die bereits weniger als eine Milliarde nach dem Urknall hundert Mal schneller Sterne bildet als unsere Milchstraße. Das könnte einen früheren Befund erklären: eine Population überraschend massereicher Galaxien 1,5 Milliarden Jahre nach dem Urknall, deren Existenz solche Super-Produktivität voraussetzt. Die Beobachtungen zeigen außerdem das früheste bekannte Beispiel verschmelzender Galaxien. Die Ergebnisse von Roberto Decarli vom Max-Planck-Institut für Astronomie und seinen Kollegen werden am 25. Mai in der Fachzeitschrift Nature veröffentlicht.
Abbildung 1: Künstlerische Darstellung eines Quasars mit benachbarten verschmelzenden Galaxien. Die von Decarli und Kollegen beobachteten Galaxien sind soweit entfernt, dass derzeit keine detaillierten Bilder möglich sind. Diese Montage gibt einen Eindruck davon, wie sie aus der Nähe aussehen würden.
Bild: MPIA mit Bildmaterial des NASA/ESA-Weltraumteleskops Hubble
Als eine Gruppe von Astronomen vor ein paar Jahren im frühen Universum eine neue Sorte ungewöhnlich massereicher Galaxien entdeckte, gab deren schiere Größe – mit hunderten von Milliarden Sternen – ein Rätsel auf. Diese Galaxien sind so weit entfernt, dass wir sie sehen, wie sie ganze anderthalb Milliarden Jahre nach dem Urknall aussahen, als das Universum nur rund 10% so alt war wie heute. Wie konnten sie vom Urknall bis dahin, in einer vergleichsweise kurzen Zeit, bereits so viele Sterne bilden?
Jetzt zeigt ein Zufallsfund einer Astronomengruppe unter der Leitung von Roberto Decarli vom Max-Planck-Institut für Astronomie eine mögliche Lösung auf: eine Population superproduktiver Galaxien im frühesten Universum, weniger als eine Milliarde Jahre nach dem Urknall.
Roberto Decarli sagt: "Wir waren eigentlich auf der Suche nach etwas anderem gewesen: nach Sternentstehungs-Aktivität in den Wirtsgalaxien von Quasaren. In vier Fällen fanden wir allerdings etwas unerwartetes: Nachbargalaxien der Quasare, die mit großer Geschwindigkeit neue Sterne bildeten, hundert Sonnenmassen pro Jahr". Quasare sind eine kurze Phase der Galaxien-Evolution, angetrieben dadurch, das Materie auf das supermassereiche Schwarze Loch im Zentrum einer Galaxie fällt.
Fabian Walter, Leiter des Beobachtungsprogramms mit dem ALMA-Observatorium in Chile, welches zu der Entdeckung führte, sagt: "Es dürfte kein Zufall sein, dass diese produktiven Galaxien so nahe an hellen Quasaren liegen. Quasare entstehen nach heutigem Verständnis in Regionen des Universums, in denen die Materiedichte deutlich größer ist als im Durchschnitt. Dieselben Bedingungen dürften begünstigen, dass Galaxien besonders schnell neue Sterne bilden."
Ob die neu entdeckten Galaxien tatsächlich die Vorläufer ihrer massereichen späteren Verwandten sein und so das kosmische Rätsel lösen können hängt davon ab, wie häufig sie im Universum sind. Dieser Frage wollen sich Decarli und seine Kollegen mit weiteren Beobachtungen widmen.
Die ALMA-Beobachtungen zeigen außerdem eine Galaxienkonfiguration, bei der es sich offenbar um das früheste bekannte Beispiel für zwei miteinander verschmelzende Galaxien handelt. Neben der Entstehung neuer Sterne sind solche Verschmelzungen ein wichtiger Mechanismen für Galaxienwachstum – und die neuen Beobachtungen geben die ersten direkten Hinweise darauf, dass solche Verschmelzungen bereits in den frühesten Stadien der Galaxienevolution stattgefunden haben, weniger als eine Milliarde Jahre nach dem Urknall.
Die hier beschriebenen Resultate sind veröffentlicht als Decarli et al., "Rapidly star-forming galaxies adjacent to quasars at z>6" in der Ausgabe vom 25. Mai 2017 der Fachzeitschrift Nature.
Eduardo Bañados (Carnegie Observatories, Pasadena), Frank Bertoldi (Universität Bonn), Chris Carilli (NRAO und Cavendish Laboratory, Cambridge), Xiaohui Fan (University of Arizona), Dominik Riechers (Cornell University), Michael A. Strauss (Princeton University), Ran Wang (Universität Peking) und Y. Yang (Korea Astronomy and Space Science Institute).
Thousands of processors, terabytes of data, and months of computing time have helped a group of researchers in Germany create some of the largest and highest resolution simulations ever made of galaxies like our Milky Way.
A composite of images from the simulation. (Left) Projected gas density of the galaxy environment about 10 billion years ago. Depicted are filamentary gas structures that feed the main galaxy at the centre. (Middle) Bird’s eye view of the gas disc in the present day. The fine detailed spiral pattern is clearly visible. (Right) Side-on view of the same gas disc in the present day. Cold gas is shown as blue, warm gas as green and hot gas as red. Credit: Robert J. J. Grand, Facundo A. Gomez, Federico Marinacci, Ruediger Pakmor, Volker Springel, David J. R. Campbell, Carlos S. Frenk, Adrian Jenkins and Simon D. M. White. Click for a full size imageAstronomers study our own and other galaxies with telescopes and simulations, in an effort to piece together their structure and history.
Spiral galaxies like the Milky Way are thought to contain several hundred thousand million stars, as well as copious amounts of gas and dust.
The spiral shape is commonplace, with a massive black hole at the centre, surrounded by a bulge of old stars, and arms winding outwards where relatively young stars like the Sun are found.
However understanding how systems like our galaxy came into being continues to remain a key question in the history of the cosmos.
The enormous range of scales (stars, the building blocks of galaxies, are each about one trillion times smaller in mass than the galaxy they make up), as well as the complex physics involved, presents a formidable challenge for any computer model.
Using the Hornet and SuperMUC supercomputers in Germany and a state-of-the-art code, the team ran 30 simulations at high resolution, and 6 at very high resolution, for several months.
The dark matter density 500 million years after the Big Bang, centred on what would become the Milky Way. Red, blue and yellow colours indicate low, intermediate and high density regions. Credit: Robert J. J. Grand, Facundo A. Gomez, Federico Marinacci, Ruediger Pakmor, Volker Springel, David J. R. Campbell, Carlos S. Frenk, Adrian Jenkins and Simon D. M. White. Click for a full size imageThe code includes one of the most comprehensive physics models to date. It includes phenomena such as gravity, star formation, hydrodynamics of gas, supernova explosions, and for the first time the magnetic fields that permeate the interstellar medium (the gas and dust between the stars).
Black holes also grew in the simulation, feeding on the gas around them, and releasing energy into the wider galaxy.
Dr Grand and his team were delighted by the results of the simulation. "The outcome of the Auriga Project is that astronomers will now be able to use our work to access a wealth of information, such as the properties of the satellite galaxies and the very old stars found in the halo that surrounds the galaxy."
The team also see the effect of those smaller galaxies, in some cases spiralling into the larger galaxy early in its history, in a process that could have created large spiral discs.
Dr Grand adds: "For a spiral galaxy to grow in size, it needs a substantial supply of fresh star-forming gas around its edges - smaller gas-rich galaxies that spiral gently into ours can provide exactly that."
The scientists will now combine the results of the Auriga Project work with data in surveys from observatories like the Gaiamission, to better understand how mergers and collisions shaped galaxies like our own.
Atomic-scale imaging improves dating of planetary events
Research led by the University of Portsmouth has identified a new way to improve how we measure the age of planetary evolution in our solar system.
The study, published in Nature Communications, uses a new atomic-scale imaging approach to locate and count individual atoms in planetary materials. Directly linking the structure and chemistry of minerals in this way opens up new opportunities to understand the spectacular complexity of planetary samples.
Meteorites provide samples that can be used to measure the timing of major planetary events, including lunar magma ocean crystalisation, Martian volcanism and asteroid bombardment of the inner solar system. However, due to shock metamorphism – extreme deformation and heating that occurs during impact events – samples often give a mixed age between the formation of the rock and timing of shock metamorphism. This makes it difficult to build an accurate timescale of when planetary events occurred.
The 11 nano tips used in the study.
Using atom probe tomography (APT), the researchers were able to accurately date such events in baddeleyite (ZrO2), a relatively common but small uranium bearing mineral in planetary igneous rocks. Atom probe tomography provides 3D atom-by-atom imaging of materials with a uniquely powerful combination of spatial and chemical resolution. It takes tiny grains of the mineral, approximately 1,000th the width of a human hair, and energises atoms one at a time using a laser. This allows researchers to reconstruct 3D atom scale models of the material, and visualise the extent of deformation. Counting individual uranium and lead atoms within these domains enables accurate radiometric dating of the associated planetary events. The samples were taken from a 1.85 billion year old impact structure at Sudbury, approximately 400 km north of Toronto, Canada.
The research was led by PhD student, Lee White. Lee said: “Because of the challenges scientists face in dating these complex materials, many meteorites could be older than previously thought. This could affect what we think regarding the age of the major planetary events in our solar system.
“The ability to generate targeted, high-precision ages with APT shows great promise when examining tiny baddeleyite grains in meteorites. As we are able to identify and sample at the nanoscale, it opens up new avenues for dating highly deformed materials and provides an exceptional opportunity to accurately measure timings of major solar system events.”
Co-author and Lee’s supervisor Dr James Darling, Senior Lecturer in Geology in the School of Earth and Environmental Sciences, said: “By imaging the location of individual atoms, this new approach provides the incredible ability to resolve how deformation can affect the chemistry of materials. In this case, we have imaged uranium and lead isotopes to essentially see complex patterns of time itself.”
The research was a collaboration with CAMECA Instruments, a major US-based international manufacturer of scientific equipment, and Western University, Canada. James and Lee conducted their analysis at the CAMECA facilities in Madison (Wisconsin, USA) and also at Western University (London, Ontario) in Canada.
Understanding Star Formation in the Nucleus of Galaxy IC 342
An international team of researchers used NASA’s Stratospheric Observatory for Infrared Astronomy, SOFIA, to make maps of the ring of molecular clouds that encircles the nucleus of galaxy IC 342. The maps determined the proportion of hot gas surrounding young stars as well as cooler gas available for future star formation. The SOFIA maps indicate that most of the gas in the central zone of IC 342, like the gas in a similar region of our Milky Way Galaxy, is heated by already-formed stars, and relatively little is in dormant clouds of raw material.
At a distance of about 13 million light years, galaxy IC 342 is considered relatively nearby. It is about the same size and type as our Milky Way Galaxy, and oriented face-on so we can see its entire disk in an undistorted perspective. Like our galaxy, IC 342 has a ring of dense molecular gas clouds surrounding its nucleus in which star formation is occurring. However, IC 342 is located behind dense interstellar dust clouds in the plane of the Milky Way, making it difficult to study by optical telescopes.
The team of researchers from Germany and the Netherlands, led by Markus Röllig of the University of Cologne, Germany, used the German Receiver for Astronomy at Terahertz frequencies, GREAT, onboard SOFIA to scan the center of IC 342 at far-infrared wavelengths to penetrate the intervening dust clouds. Röllig’s group mapped the strengths of two far-infrared spectral lines – one line, at a wavelength of 158 microns, is emitted by ionized carbon, and the other, at 205 microns, is emitted by ionized nitrogen.
The 158-micron line is produced both by cold interstellar gas that is the raw material for new stars, and also by hot gas illuminated by stars that have already finished forming. The 205-micron spectral line is only emitted by the hot gas around already-formed young stars. Comparison of the strengths of the two spectral lines allows researchers to determine of the amount of warm gas versus cool gas in the clouds.
Röllig’s team found that most of the ionized gas in IC 342’s central molecular zone (CMZ) is in clouds heated by fully formed stars rather than in cooler gas found farther out in the zone, like the situation in the Milky Way’s CMZ. The team’s research was published in Astronomy and Astrophysics, volume 591.
“SOFIA and its powerful GREAT instrument allowed us to map star formation in the center of IC 342 in unprecedented detail,” said Markus Röllig of the University of Cologne, Germany, “These measurements are not possible from ground-based telescopes or existing space telescopes.”
Researchers previously used SOFIA’s GREAT spectrometer for a corresponding study of the Milky Way’s CMZ. That research, published in 2015 by principal investigator W.D. Langer, et. al, appeared in the journal Astronomy & Astrophysics 576, A1; an overview of that study can be found here.
SOFIA is a Boeing 747SP jetliner modified to carry a 100-inch diameter telescope. It is a joint project of NASA and the German Aerospace Center, DLR. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is based at NASA’s Armstrong Flight Research Center's Hangar 703, in Palmdale, California.
First Science Results from Juno Show Surprises in Jupiter's Atmosphere and Interior
Newly-released, enhanced color view of Jupiter’s south pole from Juno as seen on Dec. 11, 2016. The image was taken from an altitude of about 32,400 miles (52,200 kilometers) above the planet’s beautiful cloud tops. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Gabriel Fiset
There has been a lot of attention given to the Cassini mission at Saturn lately, but meanwhile, NASA’s Juno probe also continues to be busy studying the largest planet in the Solar System, Jupiter. Juno is now revealing more of the giant planets’ secrets, and the first science resultshave now been published, which were presented last week at the European Geosicences Union meeting. As is common in planetary science, the new findings include significant surprises.
As it turns out, Jupiter’s interior seems to be rather different from what had been expected. Being a gas giant, Jupiter doesn’t have a surface as such below the atmosphere, it just gets progressively denser the farther down you go until you reach (as thought) a small, solid core.
“The whole inside of Jupiter is just working differently than our models expected,” said mission principal investigator Scott Bolton of the Southwest Research Institute in Texas.
Artist’s conception of Juno orbiting Jupiter. Juno has already changed scientists’ views and understanding of the giant planet’s atmosphere and interior. Image Credit: NASA/JPL-Caltech
Previous models of Jupiter’s interior had been based on gravitational measurements of the planet, but the new findings appear to suggest something different. Jupiter’s interior, beneath the deep and turbulent atmosphere, was thought to be fairly uniform, with a shallow outer layer of liquid hydrogen overlying a thinner layer. In that thinner layer, it would “rain” helium. Farther down was a deeper layer of metallic hydrogen, and finally a smaller solid core, about 43,000 miles (70,000 kilometers) down. But now it seems, from Juno’s data, that those layers are not as uniform as previously thought.
“Jupiter’s molecular envelope is not uniform,” said Tristan Guillot of the University of the Cote d’Azur in France. “We assumed we could treat the envelope as global, but now, with the finer data, it appears less regular.”
Instead of a solid core, the data suggests that Jupiter has a more “fuzzy” core, which is dilutely mingled with the overlying metallic hydrogen layer. In short, Jupiter’s interior is more complex that first thought, which is an exciting find for scientists who want to understand how larger gas planets form and evolve.
The surprises also include the atmosphere as well. It’s been known for a long time that Jupiter has ammonia clouds, but Juno found that there is a dense, deep zone of ammonia gas around the equator, something not expected. Another parts of the atmosphere, ammonia is depleted, which is evidence for amonnia-based weather systems on Jupiter.
“We’ve known there’s a spike at the equator, but the new microwave data is showing that the spike goes way, way down into the abyss, 300 kilometres below the cloud,” said Leigh Fletcher of the University of Leicester, UK. “It suggests ammonia is being distributed by a weather system that penetrates much deeper than anyone expected.”
The new findings also extend beyond the planet itself as it were, with the discovery that Jupiter’s magnetic field is stronger and more irregular than first thought. The strength of the magnetic field was previously estimated to be about 5 gauss (compared to 0.25 to 0.65 gauss for Earth), but Juno found it to be possibly as high as 8-9 gauss. The dynamo which drives the magnetic field is now thought to be closer to the surface than expected.
Another view of Jupiter’s south pole, in enhanced color, as seen by Juno during its fourth flyby on Feb. 2, 2017. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/John Landino
Jupiter’s north pole, as seen by Juno during its fifth flyby on March 27, 2017. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko
“I didn’t expect all the theories to be wrong, but there’s motion going on in the planet we did not anticipate,” Bolton said.
“Jupiter’s magnetic field is spatially complex, and there were deficits of up to 2 gauss elsewhere,” noted Connerney. “We may need many more orbits to resolve this.”
In March, Juno completed its fifth close flyby of Jupiter. Closest approach occurred on Monday, March 27, at 1:52 a.m. PDT (4:52 a.m. EDT, 8:52 UTC). All of the spacecraft’s science instruments were operating during the flyby; scientists now have even more data to go through from the mission so far.
As mentioned by Bolton last February, “This will be our fourth science pass – the fifth close flyby of Jupiter of the mission – and we are excited to see what new discoveries Juno will reveal. Every time we get near Jupiter’s cloud tops, we learn new insights that help us understand this amazing giant planet.”
Crescent Jupiter, with two of its moons, Europa and Io, as seen by Juno during its fifth flyby on March 27, 2017. This is a view never possible from Earth. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko
Enhanced color view from Juno’s fifth flyby on March 27, 2017. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko
Another enhanced color view from Juno’s fifth flyby on March 27, 2017, from a distance of only 3,728 miles (6,000 kilometers). Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko
Juno has also found previously unseen swirling cyclones in Jupiter’s atmosphere, similar to cyclones on Earth, but much larger.
As Glenn Orton of the Jet Propulsion Laboratory in Pasadena, California told New Scientist, “They’re the size of Earth, or maybe half an Earth. They’re probably composed of condensed ammonia.”
Juno has also seen other white ovals, in the cloud belts south of Jupiter’s equator. Their composition isn’t known for certain yet, but according to Alberto Adriani of the Institute for Space Astrophysics and Planetology in Rome, Italy, they likely contain ammonia and hydrazine. On Earth, hydrazine is used in rocket fuel.
As well as the atmosphere, Juno has also been studying Jupiter’s auroras. These are again similar to what we see on Earth, but more intense. The regions at the poles where they occur are composed mostly of methane and an ion containing three hydrogen atoms (H3+), at temperatures ranging from 500 to 950 kelvin.
Jupiter as seen from Earth: stunning new image taken by the Hubble Space Telescope on April 3, 2017. Photo Credit: NASA/ESA/A. Simon (GSFC)
And of course there are the images. Juno has been taking the highest-resolution images of Jupiter during its mission, including of the polar regions. They can often look like works of art– the clouds, storms and eddies in the atmosphere appearing like they were painted by a cosmic hand. Jupiter’s visible atmosphere is extremely turbulent, but that just adds to its beauty. The camera itself has also proven to be more resilient than anticipated, despite being hit by Jupiter’s radiation on an on-going basis.
“The good news is radiation damage so far is almost negligible, so it will operate for many years,” Orton said.
Last February, it was announced that Juno would remain in the same orbit for the remainder of its mission, due to a problem with the main engine. This doesn’t adversely affect the health of the spacecraft, but it means that Juno won’t be able to orbit even closer to Jupiter. The orbit it’s in right now is an elongated 56-day orbit. Juno was supposed to then switch to a closer, 14-day orbit, but the engine problem meant that the new orbit might be less than desirable, so it was decided by the mission team that the spacecraft would remain in the same orbit it is in now, for the rest of the mission. That won’t affect the science obtained too much however. It also means that the spacecraft will be subjected to less radiation overall, another plus.
“Another key advantage of the longer orbit is that Juno will spend less time within the strong radiation belts on each orbit,” said Bolton. “This is significant because radiation has been the main life-limiting factor for Juno.”
Intricate cloud formations in Jupiter’s atmosphere, from Juno’s fourth flyby on Feb. 2, 2017. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Björn Jónsson
“Juno is providing spectacular results, and we are rewriting our ideas of how giant planets work,” said Bolton. “The science will be just as spectacular as with our original plan.”
Apart from Juno, the Hubble Space Telescope also recently took some breathtaking new images of Jupiter, showing the well-known distinctive dark bands and the Great Red Spot. Hubble is able to see features as small as 80 miles (130 kilometers) across in Jupiter’s atmosphere.
Juno’s next closest approach to Jupiter, the sixth flyby, will be on May 19, which will include flying over the Great Red Spot, the most well-known feature on Jupiter. This will be a chance to study the massive and long-lived storm in more detail than ever before.
“It means that for the first time, we can go down deep and find out what’s going on underneath,” Fletcher said.
More information about the Juno mission is available on its NASA website.
Juno Scientists Prepare for Fifth Science Pass of Jupiter
This enhanced color view of Jupiter’s cloud tops was processed by citizen scientist Bjorn Jonsson using data from the JunoCam instrument on NASA’s Juno spacecraft. The image highlights a massive counterclockwise rotating storm that appears as a white oval in the gas giant’s southern hemisphere.
NASA's Juno spacecraft will make its fifth science flyby over Jupiter's mysterious cloud tops on Thursday, May 18, at 11 p.m. PDT (Friday, May 19, 2 a.m. EDT and 6:00 UTC). At the time of perijove (defined as the point in Juno’s orbit when it is closest to the planet's center), the spacecraft will have logged 63.5 million miles (102 million kilometers) in Jupiter’s orbit and will be about 2,200 miles (3,500 kilometers) above the planet's cloud tops.
Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida, and arrived in orbit around Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,100 miles (3,400 kilometers) During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.
NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California.
Monstrous cyclones churning over Jupiter's poles
Monstrous cyclones are churning over Jupiter's poles, until now a largely unexplored region that is more turbulent than scientists expected.
NASA's Juno spacecraft spotted the chaotic weather at the top and bottom of Jupiter once it began skimming the cloud tops last year, surprising researchers who assumed the giant gas planet would be relatively boring and uniform down low.
"What we're finding is anything but that is the truth. It's very different, very complex," Juno's chief scientist Scott Bolton of the Southwest Research Institute said Thursday.
With dozens of cyclones hundreds of miles across — alongside unidentifiable weather systems stretching thousands of miles — the poles look nothing like Jupiter's equatorial region, instantly recognizable by its stripes and Great Red Spot, a raging hurricane-like storm.
"That's the Jupiter we've all known and grown to love," Bolton said. "And when you look from the pole, it looks totally different ... I don't think anybody would have guessed this is Jupiter."
He calls these first major findings — published Thursday — "Earth-shattering. Or should I say, Jupiter-shattering."
Turning counter-clockwise in the northern hemisphere just like on Earth, the cyclones are clearly clustered near the poles. The diameters of some of these confirmed cyclones stretch up to 1,700 miles (2,800 kilometers). Even bigger, though shapeless weather systems are present in both polar regions. At the same time, the two poles don't really resemble each other, which is puzzling, according to Bolton.
Scientists are eager to see, over time, whether these super cyclones are stable or dynamic. "Are they going to stay the same way for years and years like the Great Red Spot ... Of course, only time will tell," Bolton said.
Just as intriguing will be how fast these super cyclones are moving.
Launched in 2011 and orbiting Jupiter since last summer, Juno is providing the best close-up views ever of our solar system's largest planet, peering beneath the clouds for a true portrait. It's made five close passes over Jupiter so far for science collection, the most recent last week; they occur about every two months given Juno's extremely oblong orbit. The next one will be in July, with investigators targeting the Great Red Spot.
Juno is moving so fast during these chummy encounters that it takes only two hours to get from the north pole to the south.
Besides polar cyclones, Juno has spotted white ice caps on Jupiter — frozen bits of ammonia and water. Bolton refers to them as Jovian snowfall — or maybe hail.
Juno also has detected an overwhelming abundance of ammonia deep down in Jupiter's atmosphere, and a surprisingly strong magnetic field in places — roughly 10 times greater than Earth's. It's also led scientists to believe Jupiter may have a "fuzzy" core — as Bolton puts it — big but partially dissolved.
Then there are the eerie sounds of plasma waves at Jupiter — "nature's music," according to Bolton. During the teleconference, he played two minutes of the spacecraft's recording from February, adjusted for the human ear and full of percussion sounds as well as high-pitched beeps and squeals, and even flute-like notes.
Results were published in Science and Geophysical Research Letters.
Jupiter's poles appear dramatically different from neighboring Saturn's, according to the scientists, with nothing like the hexagon-shaped cloud system over Saturn's north pole.
Researchers hope to compare Juno's observations with those of NASA's Cassini spacecraft, in its final months orbiting Saturn.
Juno's findings are "really going to force us to rethink not only how Jupiter works, but how do we explore Saturn, Uranus and Neptune," Bolton said.
Nasa's Juno probe captures dramatic first close-up images of Jupiter
Excitement greets pictures of giant, chaotic weather systems plus new measurements that will help build unprecedented map of planet’s interior
The first close-up observations from Nasa’s Juno spacecraft have captured towering clouds, swirling cyclones and dramatic flows of ammonia that drive giant weather systems on the largest planet in the solar system.
“We were all jumping up and down with excitement when the images came down,” said Fran Bagenal, a planetary space physicist at the University of Colorado, who joined the Juno mission more than a decade ago. “You’ve got to be patient, but the rewards are fantastic.”
The spacecraft survived an almost six-year, 2.8bn km voyage across the depths of space to reach its destination, where it ducked beneath Jupiter’s intense radiation belts, turned on its suite of instruments, and swept into an orbit that loops over the planet’s north and south poles.
From 5,000km above the brown-orange blanket that covers the planet, Juno’s camera snapped pictures of tall, white storm clouds standing high above the rest. Some were so high, they stood out even on the nightside of the planet, betrayed by the feeble light of the sun glinting off them.
Yet more images revealed flashes of lightning that illuminate the Jovian sky. “The weather is dramatic,” said Bagenal. “What we thought we knew about Jupiter, we underestimated. It’s more variable, there are more features, there is much more detail the closer you look.”
Described as a “planet on steroids” by Scott Bolton, the mission’s principal investigator at the Southwest Research Institute in San Antonio, Jupiter is an enormous gas giant made from hydrogen and helium. Compared with Jupiter and the sun, the rest of the solar system is an afterthought. All of the other planets, the asteroids and comets, would fit within Jupiter, a planet 11 times wider than Earth.
Writing in twopapers in the journal Science today, the Juno team describe fresh images and measurements of the planet’s atmosphere, magnetic field and the brilliant non-stop lightshows that constitute the aurorae at Jupiter’s poles.
Its sensors peering down as it swooped around the planet, Juno spotted chaotic scenes with bright oval-shaped features swirling in the clouds. Time-lapse images revealed them to be enormous cyclones, rotating counter-clockwise in the northern hemisphere. The storms reached up to 1,400km wide, more than ten times the size of the largest cyclones on Earth. Deep inside the atmosphere, the scientists found evidence for what they called an “equatorial plume” – a massive and unexpected overturning of gas driven by a steady upward stream of ammonia from around the planet’s equator. It seems to mirror the Hadley cell convection currents on Earth, where warm air rises at the equator and falls again about 30 degrees to the north and south. But “It looks like a band that goes all the way round the middle of Jupiter,” said Bagenal. The question is where does it go down?”
Another instrument on Juno measured the magnetic field of the planet and found it to be twice as strong as scientists expected, at about ten times greater than the field that surrounds Earth. During observations of the planet’s intense aurorae, Juno detected streams of electrons hurtling down into Jupiter’s upper atmosphere, where they potentially power the spectacular light shows.
Over the coming months, Juno will build up an unprecedented map of the planet’s interior before its instruments succumb to the harsh radiation and the spacecraft plunges into the clouds at the end of its mission. Along for the ride are three Lego crew members: the Roman god Jupiter, his wife Juno, and a telescope-wielding Galileo, who discovered four of Jupiter’s 53 moons.
One mystery scientists are keen to clear up is whether Jupiter has a solid core. With more data from the orbiting Juno, it is a puzzle they hope to answer. “We’re having to put together this 3D puzzle,” Bagenal said. “And surprise, surprise, it isn’t like Earth.”
A WHOLE NEW JUPITER: FIRST SCIENCE RESULTS FROM NASA’S JUNO MISSION
Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world. Credit: NASA/JPL-CalTech/USGS.
WASHINGTON, DC — Early science results from NASA’s Juno mission to Jupiter portray the largest planet in our solar system as a complex, gigantic, turbulent world, with Earth-sized polar cyclones, plunging storm systems that travel deep into the heart of the gas giant, and a mammoth, lumpy magnetic field that may indicate it was generated closer to the planet’s surface than previously thought.
“We are excited to share these early discoveries, which help us better understand what makes Jupiter so fascinating,” said Diane Brown, Juno program executive at NASA Headquarters in Washington, D.C. “It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey.”
Juno launched on Aug. 5, 2011, entering Jupiter’s orbit on July 4, 2016. The findings from the first data-collection pass, which flew within about 2,600 miles (4,200 kilometers) of Jupiter’s swirling cloud tops on Aug. 27, are being published this week in two papers in the journal Science, as well as a 44-paper special collection in Geophysical Research Letters, a journal of the American Geophysical Union.
“We knew, going in, that Jupiter would throw us some curves,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “But now that we are here we are finding that Jupiter can throw the heat, as well as knuckleballs and sliders. There is so much going on here that we didn’t expect that we have had to take a step back and begin to rethink of this as a whole new Jupiter.”
Among the findings that challenge assumptions are those provided by Juno’s imager, JunoCam. The images show both of Jupiter’s poles are covered in Earth-sized swirling storms that are densely clustered and rubbing together.
“We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole,” said Bolton. “We’re questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we’re going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?”
Another surprise comes from Juno’s Microwave Radiometer (MWR), which samples the thermal microwave radiation from Jupiter’s atmosphere, from the top of the ammonia clouds to deep within its atmosphere. The MWR data indicates that Jupiter’s iconic belts and zones are mysterious, with the belt near the equator penetrating all the way down, while the belts and zones at other latitudes seem to evolve to other structures. The data suggest the ammonia is quite variable and co
Is North Korea using China’s satellites to guide its missiles?
Pyongyang doesn't have the funds or resources to build its own satellite navigation network.
As North Korea fires more missiles in its drive to build and test rockets to reach the US mainland, one issue largely overlooked is that satellites are among methods used to guide such weapons to their targets.
Pyongyang doesn’t have a satellite navigation network, raising speculation that if it is using such a guidance system then is it tapping into China’s?
While information on military programs in the North is difficult to verify, reports going back to 2014 show that North Korean engineers were in China for technology training on how the country’s satellite navigation system — known as Beidou or Compass — worked.
Later the same year, another news report cited a Chinese military expert as saying China cannot stop North Korea from using Beidou in military operations.
Beside Beidou, the other main satellite navigation options for North Korea are the Global Positioning System of the United States and the Russian system known as Glonass.
“While I would never exclude the possibility of Glonass applications for N Korea’s rocket and missile systems, Beidou looks like a more reasonable solution for N Korea,” said Yu Koizumi, a research fellow at Japan’s Institute for Future Engineering, in an email.
A model of China’s Beidou satellite navigation system on display in an exhibition in Beijing, China, 7 June 2016. China is expanding the system to improve intelligence gathering in the South China Sea, according to the government. Photo: AFP.
Russia imposed an embargo on transfers of weapons and military-related technologies to North Korea after its nuclear tests in the 2000s, although it’s unclear if Glonass-related equipment was included, said Koizumi, a specialist in Russia’s security policy.
Launches of Beidou satellites started in 1994 and have resulted in China deploying a system in East Asia and beyond that is akin to the GPS. Like GPS, Beidou supports two varieties of service: One for civilian and commercial use, and another more robust, supposedly jam-proof, and more precise for military users.
When 59 Tomahawk missiles launched by US Navy destroyers struck their targets in Syria in early April, they were probably guided to their targets by GPS, although Tomahawks are equipped with other guidance systems as well.
Japan, which has its own variant of GPS that will ultimately involve 7 satellites in orbit over Japan and the surrounding region, is now seeking to acquire Tomahawk missiles or develop their own version.
While it hasn’t been confirmed that the military version of Beidou is being used by North Korea, it seems questionable that the civilian version would be applied to the precision-guided munitions (PGMs) that Pyongyang has hidden away on mobile missile and rocket launchers.
The civilian version of Beidou would be vulnerable to electronic jamming by the US, Japan or South Korea and that is unlikely to be acceptable to Pyongyang’s military in the event of a conflict.
“North Korea would need specific chips, and presumably Chinese cooperation, to use China’s more precise non-public signal,” said Gregory Kulacki, senior analyst and the China Project manager for the Global Security Program of the Union of Concerned Scientists.
During the April 15 military parade in Pyongyang, an upgraded KN-09 300mm Multiple Launch Rocket System (MLRS) was on display, which has a range of 200 kilometers.
Part of North Korea’s missile arsenal. Photo: AFP/North Korean Central News Agency
According to James Lewis, senior vice president at the Center for Strategic and International Studies in Washington DC, it is feasible that the KN-09 could use a hybrid Beidou and Glonass signal to enhance its reliability and accuracy.
Lewis described the KN-09 as a funny system that is copied from a Chinese MLRS, which itself was copied from a Russian MLRS that used Russia’s Glonass system.
“It would not be that hard for the Chinese to add Beidou,” said Lewis via email, adding that solid evidence isn’t available.
North Korea could also use terrain mapping and other more sophisticated capabilities, such as inertial guidance mounted aboard its medium and long-range missiles.
Still, the prospect remains Pyongyang may be using Beidou to make sure missiles aimed at US soldiers on military bases in Asia hit their targets. It’s the same case for North Korea’s stated intention to build missiles that can reach the continental US.
This scenario demands that Washington get clarification from Beijing about the extent if any of North Korea’s access to Beidou, especially considering the comment by the China military expert cited earlier.
Estimated ranges of known North Korean missiles.
As concerns mount over the escalating efforts by Pyongyang to improve its missile systems as well as nuclear weaponry, China plans to add at least 30 new Beidou satellites by 2020 to join the 20-plus currently in operation, greatly adding to its accuracy and capabilities.
This expansion will include construction of dozens of monitoring stations on the ground inside China as well as in other countries.
Ran Chengqi, director of the China Satellite Navigation Office, last year told a news conference that this will improve the accuracy of the Beidou system down to decimeters rather than meters.
The civilian dimension is significant in itself. In 2015, more than 400 million Beidou-equipped smartphones were sold in China, according to the Global Navigation Satellite System and Location Based Services Association of China.
Today, Chinese smartphone users with Beidou-based services number between 700 and 800 million and by 2020, Beidou’s global market footprint should expand to 60 percent of total devices sold or roughly three times the number in 2015.
Meantime, Beidou plays a significant role in all aspects of China’s military operations, including in the South China Sea for intelligence gathering as well as two-way messaging.
In January, Jordan Wilson, a policy analyst at the US-China Economic and Security Review Commission, said the Beidou program could cost China as much as $US10 billion by 2020.
He described China’s deployment and development of precision-guided munitions as “the central feature of China’s anti-access/area denial objective within its People’s Liberation Army’s missions, intended to make a US military intervention in the Western Pacific more costly.”
North Korea’s anti-access/area denial objective is complementary to China’s, and thus not outlandish to assume that Beijing has granted its neighbor access to the Beidou military signal capabilities.
China has always been a willing endorser of a well-armed North Korea and seldom if ever criticizes Pyongyang’s efforts to expand and enhance its arsenal of conventional weapons.
Right now, though, the US needs to focus on the scope of Beidou’s role in North Korea’s missile program and initiate a discussion about it with Beijing.
Perhaps the question of Beidou and its role in guiding North Korea’s growing fleet of drones should be on the agenda, too.
Beginn der Bauarbeiten von ELT-Kuppel und Teleskop
Michelle Bachelet Jeria, die Präsidentin der Republik Chile, hat an einer Zeremonie zur Grundsteinlegung des Extremely Large Telescope (ELT) der ESO teilgenommen, die am Paranal-Observatorium im Norden Chiles in der Nähe des Standorts des zukünftigen Riesenteleskops stattgefunden hat. Dieser Meilenstein ist der Startschuss für die Bauphase von Kuppel und Teleskopstruktur des weltgrößten Teleskops für das sichtbare Licht und leitet eine neue Ära in der Astronomie ein. Gleichzeitig wurde das Obseravtorium an das nationale chilenische Elektrizitätsnetz angeschlossen.
Tim de Zeeuw, der Generaldirektor der ESO, Roberto Tamai, der ELT-Programmmanager und Andreas Kaufer, der Direktor des La Silla-Paranal-Observatoriums empfingen Präsidentin Bachelet. Ebenfalls anwesend waren Aurora Williams, die Ministerin für Bergbau, Wirtschaftsminister Luis Felipe Céspedes und Andrés Rebolledo, der Energieminister. An der Zeremonie nahmen zusätzlich viele angesehene internationale und chilenische Gäste aus Politik und Industrie teil, dazu ESO-Wissenschaftler und Ingenieure sowie Vertreter lokaler und internationaler Medien .
Höhepunkt der Zeremonie war das Versiegeln einer Zeitkapsel, die die ESO vorbereitet hatte. Sie enthält ein Poster mit Fotografien derzeitiger ESO-Mitarbeiter und ein Exemplar des des Buchs, das die wissenschaftliche Zielsetzung des Teleskops beschreibt. Die Abdeckung der Zeitkapsel besteht aus einem gravierten Sechseck aus Zerodur®, das einem Modell eines der Hauptspiegelsegmente des ELT im Maßstab 1:5 entspricht.
In ihrer Rede betonte die Präsidentin: “Mit dem symbolischen Beginn dieser Bauarbeiten errichten wir mehr als nur ein Teleskop: Es stellt in beispielloser Art und Weise unsere wissenschaftlichen und technologischen Möglichkeiten dar und demonstiert das gewaltige Potential nternationaler Zusammenarbeit.”
Tim de Zeeuw bedankte sich bei der Präsidentin und ihrer Regierung für ihre kontinuierliche Unterstützung der ESO in Chile und den Schutz der beispiellosen Nachthimmelsqualität im Land: “Das ELT wird entdeckungen machen, die wir heute noch gar nicht vorhersehen können, und es wird mit Sicherheit unzählige Menschen auf der ganzen Welt dazu inspirieren, über Wissenschaft, technologie und unseren Platz im Univerum nachzudenken. All das zum Wohle der ESO-Mitgliedsländer, für Chile und den Rest der Welt.”
Patrick Roche, der Präsident des ESO-Rats, fügt hinzu: "Dies ist ein Meilenstein in der Geschichte der ESO, das ELT wird das leistungsfähigste und ehrgeizigste Teleskop seiner Art sein. An diesem Punkt sind wir nur dank der langjährigen Anstrengungen unzähliger Menschen in den ESO-Mitgliedsländern, in Chile und anderswo angelangt. Ich möchte mich bei all diesen Leuten bedanknen und freue mich sehr, viele von ihnen heute hier zu sehen, um diesen Augenblick zu feiern."
Mit einem Hauptspiegeldurchmesser von 39 Metern wird das Extremely Large Telescope (ELT) das größte optisch-nahinfrarote Teleskop der Welt sein und den Teleskopebau in eine neue Welt führen. Das Teleskop wird von einem gewaltigen drehbaren Kuppelbau mit 85 Metern Durchmesser geschützt – vergleichbar mit der Fläche eines Fußballfelds.
Vor einem Jahr hat die ESO mit dem ACe-Konsortium bestehend aus Astaldi, Cimolai und der EIE Group als nominiertem Subkontraktor einen Vertrag über den Bau von Kuppel und Teleskopstruktur geschlossen (eso1617). Dabei handelte es sich um den Vertrag mit dem größten finanziellen Volumen , den die ESO jemals abgeschlossen hat, und gleichzeitig auch um den größten in der bodengebundenen Astronomie überhaupt. Mit der Grundsteinlegung hat der Bau von ELT-Kuppel und Teleskopstruktur nun auch offiziell begonnen .
Die Zeremonie markiert gleichzeitig die Anbindung der ESO-Standorte Cerro Paranal und Cerro Armazones an das nationale chilenische Elektrizitätsnetz. Die Anbindung wurde durch die Unterstützung der chilenischen Regierung möglich gemacht und wird von der chilenischen Grupo SAESA verwaltet. Durch die Anbindung werden Kosten reduziert und gleichzeitig Verlässlichkeit und Stabilität der Stromversorgung erhöht. Außerdem bessert sich dadurch die CO2-Bilanz des Observatoriums.
Das ELT ist nur das jüngste der vielen Projekte der ESO über mehr als ein halbes Jahrhundert hinweg, das von der kontinuierlichen Unterstützung der Regierung des Gastlands Chile profitiert. Der starke Rückhalt des Außenministeriums, des Energieministeriums (Minenenergia) und der Nationalen Energiekommission (CNE) hat sich bei der erfolgreichen Anbindung des Standorts an das Elektrizitätsnetz als äußerst wertvoll erwiesen.
Das Gelände, auf dem das ELT errichtet werden wird, wurde von der chilenischen Regierung gestiftet und ist außerdem durch eine große Konzession für die umgebenden Ländereien geschützt, die den ungestörten Betrieb des Teleskops in der Zukunft erst möglich machen – und damit dazu beiträgt, des Status Chiles als führender astronomischer Standort zu sichern.
Das ELT wird das größte "Auge" sein, das man bis dato an den Himmel richten wird und vermutlich unsere Wahrnehmung des Universums revolutionieren. Es wird sich einigen der größten astronomischen Herausforderungen unserer Zeit annehmen, darunter Tests von erdähnlichen Exoplaneten auf Spuren von Leben, die Beobachtung der frühen Stadien des Universums, um unsere Ursprünge zu erforschen, und die Natur der Dunklen Materie und der Dunklen Energie zu verstehen. Es wird neue Fragen aufwerfen, an die heutzutage noch gar nicht gedacht wird und dank neu entwickelter Technologien und ingenieurtechnischer Durchbrüche auch die Lebensqualität auf der Erde verbessern.
Sein "Erstes Licht" soll das ELT im Jahr 2024 einfangen. Die Grundsteinlegung markiert den Beginn einer neuen Ära in der Astronomie.
 Die Zeremonie wurde aufgrund starker Winde vom zukünftigen Teleskopstandort auf dem Cerro Armazones an die Paranal-Residencia verlegt.
 Die Kuppel wird insgesamt 5000 Tonnen wiegen, während die Montierung des Teleskops und die Tubusstruktur eine bewegliche Masse von mehr als 3000 Tonnen aufweisen werden. In beiden Fällen handelt es sich um die mit Abstand größten jemals für ein optisches bzw. nahinfrarotes Teleskop errichteten Strukturen, was das ELT wortwörtlich zum weltgrößten Auge auf den Himmel machen wird.
Künstlerische Darstellung des ELT in Betrieb
Diese künstlerische Darstellung zeigt das Extremely Large Telescope auf dem Cerro Armazones im Norden Chiles in Betrieb. Das Teleskop ist hier zusammen mit den eingeschalteten Lasern gezeigt, die künstliche Sterne in der Hochatmosphäre erzeugen. An der Grundsteinlegungszeremonie für das Teleskop am 26. Mai 2017 nahm die chilenische Präsidentin Michelle Bachelet Jeria teil.
Die sechseckige Plakette zum Versiegeln der ELT-Zeitkapsel
Dieser Aufdruck befindet sich auf einem sechseckigen Stück Zerodur-Glaskeramik, mit dem man am 26. Mai 2017 anlässlich der Grundsteinlegungszeremonie für das Extremely Large Telescope der ESO eine Zeitkapsel versiegelt hat. Es entspricht einem Modell eines der Hauptspiegelsegmente des ELT im Maßstab 1:5.
Die Messinstrumente des ELT
Diese Infografik zeigt ein vereinfachtes Schema des Aufbaus des ELT mit schwerpunkt auf seinen Instrumenten erster Generation. Das ELT soll sein "Erstes Licht" im Jahr 2024 einfangen, die Instrument dann 2025.
Camera on NASA’s Lunar Orbiter Survived 2014 Meteoroid Hit
On Oct.13, 2014 something very strange happened to the camera aboard NASA’s Lunar Reconnaissance Orbiter (LRO). The Lunar Reconnaissance Orbiter Camera (LROC), which normally produces beautifully clear images of the lunar surface, produced an image that was wild and jittery. From the sudden and jagged pattern apparent in the image, the LROC team determined that the camera must have been hit by a tiny meteoroid, a small natural object in space.
The first wild back-and-forth line records the moment on October 13, 2014 when the left Narrow Angle Camera's radiator was struck by a meteoroid.
Credits: NASA's Goddard Space Flight Center/Arizona State University
LROC is a system of three cameras mounted on the LRO spacecraft. Two Narrow Angle Cameras (NACs) capture high resolution black and white images. The third Wide Angle Camera captures moderate resolution images using filters to provide information about the properties and color of the lunar surface.
The NAC works by building an image one line at a time. The first line is captured, then the orbit of the spacecraft moves the camera relative to the surface, and then the next line is captured, and so on, as thousands of lines are compiled into a full image.
According to Mark Robinson, professor and principal investigator of LROC at ASU’s School of Earth and Space Exploration, the jittery appearance of the image captured is the result of a sudden and extreme cross-track oscillation of the camera. LROC researchers concluded that there must have been a brief violent movement of the left Narrow Angle Camera.
There were no spacecraft events like solar panel movements or antenna tracking that might have caused spacecraft jitter during this period. “Even if there had been, the resulting jitter would have affected both cameras identically,” says Robinson. “The only logical explanation is that the NAC was hit by a meteoroid.”
The Narrow Angle Camera sits on a bench in the clean room at Malin Space Science Systems. The radiator (right) extends off the electronics end and keeps the sensor cool while imaging the moon. Computer modeling shows the meteoroid impacted somewhere on the radiator.
Credits: Malin Space Science Systems/Arizona State University
How big was the meteoroid?
During LROC’s development, a detailed computer model was made to insure the NAC would not fail during the severe vibrations caused by the launch of the spacecraft. The computer model was tested before launch by attaching the NAC to a vibration table that simulated launch. The camera passed the test with flying colors, proving its stability.
Using this detailed computer model, the LROC team ran simulations to see if they could reproduce the distortions seen on the Oct. 13 image and determine the size of the meteoroid that hit the camera. They estimate the impacting meteoroid would have been about half the size of a pinhead (0.8 millimeter), assuming a velocity of about 4.3 miles (7 kilometers) per second and a density of an ordinary chondrite meteorite (2.7 grams/cm3).
“The meteoroid was traveling much faster than a speeding bullet,” says Robinson. “In this case, LROC did not dodge a speeding bullet, but rather survived a speeding bullet!”
How rare is it that the effects of an event like this were captured on camera? Very rare, according to Robinson. LROC typically only captures images during daylight and then only about 10 percent of the day, so for the camera to be hit by a meteor during the time that it was also capturing images is statistically unlikely.
“LROC was struck and survived to keep exploring the moon,” says Robinson, “thanks to Malin Space Science Systems’ robust camera design.”
“Since the impact presented no technical problems for the health and safety of the instrument, the team is only now announcing this event as a fascinating example of how engineering data can be used, in ways not previously anticipated, to understand what is happing to the spacecraft over 236,000 miles (380,000 kilometers) from the Earth," said John Keller, LRO project scientist from NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon.
“A meteoroid impact on the LROC NAC reminds us that LRO is constantly exposed to the hazards of space,” says Noah Petro, deputy project scientist from NASA Goddard. “And as we continue to explore the moon, it reminds us of the precious nature of the data being returned.”
LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, as a project under NASA's Discovery Program. The Discovery Program is managed by NASA's Marshall Spaceflight Center in Huntsville, Alabama, for the Science Mission Directorate at NASA Headquarters in Washington.
The Lunar Reconnaissance Orbiter Camera was developed at Malin Space Science Systems in San Diego, California and Arizona State University in Tempe.
This rocky outcrop at Sudbury is where the crystals of baddeleyite came from -- crystals that are now being used in a new technology to help date when meteorite strikes took place. Photo by Des Moser/Western University
Almost two billion years ago, a 10-kilometre-wide chunk of space slammed down into rock near what is now the city of Sudbury. Now, scientists from Western University and the University of Portsmouth are marrying details of that meteorite impact with technology that measures surrounding crystal fragments as a way to date other ancient meteorite strikes.
The pioneering technique is helping add context and insight into the age of meteor impacts. And ultimately, it provides new clues into the beginnings of life on this planet and others, said Desmond (Des) Moser, associate professor in the Departments of Earth Sciences and Geography at Western.
“The underlying theme is, when did life begin? We know that it couldn’t happen as long as the surface was being periodically vaporized by meteorite strikes during the solar system’s early years and youth — so if we can figure out when those strikes stopped, we can then understand a bit more about how we got here, and when.”
In this instance, researchers have been able to use new imaging techniques to measure the atomic nanostructure of ancient crystals at impact locations, using the 150-kilometre-wide crater at Sudbury as a test site.
Shock waves from that meteorite impact deformed the minerals that made up the rock beneath the crater, including small, tough crystals that contain trace amounts of radioactive uranium and lead. “These can be used as tiny clocks that are the basis for our geologic time scale,” Moser said. “But because these crystals are a banged-up mess, conventional methods won’t help in extracting age data from them.”
An international team using specialized instruments at Western’s Zircon and Accessory Phase Laboratory (ZAPLab) and a new instrument called the atom probe, at CAMECA Laboratories in the US, have made that job easier. With the probe, researchers are able to slice and lift out tiny pieces of crystal baddeleyite which is common in terrestrial, Martian and lunar rocks and meteorites.
Then Moser’s team – including researcher Lee White and co-supervisor James Darling of the University of Portsmouth – measured the deformation in the crystals after sharpening and polishing the pieces into extremely fine needles, then evaporated and identified the atoms and their isotopes layer by layer. The result is a 3D model of the atoms and their positions.
“Using the atom probe to go from the rock to the crystal to its atomic level is like zooming in with the ultimate Google Earth,” Moser says. This atomic-scale approach holds great potential in establishing a more accurate chronology of the formation and evolution of planetary crusts.
This so-called "massive fail," spotted in a nearby galaxy, could explain why so few massive stars have been observed going supernova, researchers conducting a new study explained. As many as 30 percent of these massive stars may instead quietly collapse into a black hole.
"The typical view is that a star can form a black hole only after it goes supernova," Christopher Kochanek, co-author on the paper and an astronomer at Ohio State University, said in a statement. "If a star can fall short of a supernova and still make a black hole, that would help to explain why we don't see supernovae from the most massive stars."
The dying star was about 25 times as massive as Earth's sun and located in NGC 6946, a spiral galaxy 22 million light-years from Earth. (Astronomers nickname this galaxy the "Fireworks Galaxy" because so many supernovas happen there, including recently discovered SN 2017eaw.)
One star in this galaxy, called N6946-BH1, began to brighten weakly in 2009. It vanished altogether in 2015, and the researchers, who had been monitoring the sky with the Large Binocular Telescope in Arizona, could not see signs of a supernova in that zone. So astronomers aimed two more powerful space telescopes — Hubble and Spitzer — toward the area to see if the star had faded a little, or was hidden behind a dust cloud.
With searches coming up empty, astronomers eliminated other possibilities and concluded that N6946-BH1 had turned directly into a black hole.
"N6946-BH1 is the only likely failed supernova that we found in the first seven years of our survey," Scott Adams, a former Ohio State University student who earned his doctorate as a co-author of this work, said in the statement. "During this period, six normal supernovae have occurred within the galaxies we've been monitoring, suggesting that 10 to 30 percent of massive stars die as failed supernovae."
"This is just the fraction that would explain the very problem that motivated us to start the survey, that is, that there are fewer observed supernovae than should be occurring if all massive stars die that way," he added.
Another co-author, Ohio State astronomer Krzysztof Stanek, suggested that stars collapsing directly into black holes may actually make more sense than a supernova collapsing into a black hole. That's because the supernova blows off much of a star's outer layers, leaving little mass behind to create a massive black hole, he said in the statement.