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  • richardmitnick 12:19 pm on November 23, 2016 Permalink | Reply
    Tags: Asteroids, ,   

    From Rutgers: “Asteroid Impacts Could Create Habitats for Life” 

    Rutgers University
    Rutgers University

    11.23.16
    No writer credit

    An international team of 38 scientists, including Rutgers’ Sonia Tikoo, has shown how large asteroid impacts deform rocks and possibly create habitats for early life on Earth and elsewhere.

    Around 65 million years ago, a massive asteroid crashed into the Gulf of Mexico, causing an impact so huge that the blast and its aftermath wiped out about 75 percent of all life on Earth, including most of the dinosaurs. It’s known as the Chicxulub impact.

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    Split drill cores collected from the peak ring of Chicxulub crater. The left two cores consist of basement granite. The right two cores are impact melt rocks that were created by the heat associated with the impact. Photo: E. Le Ber

    In April and May, scientists on an offshore expedition drilled deep into part of the Chicxulub impact crater. Their mission was to retrieve samples from the rocky inner ridges of the crater – known as the “peak ring” – drilling about 1,600 to 4,380 feet below the modern-day sea floor to learn more about the ancient cataclysmic event.

    Now, the researchers have performed the first analysis of the core samples in a study published online today in the journal Science. They found that the impact deformed the peak ring rocks, making them more porous and less dense than models had predicted.

    “Chicxulub crater is the only crater on Earth that has such a well-preserved peak ring and since we can’t get samples of peak rings from other planets yet, it’s really our best window into understanding the formation of large impact basins anywhere in the solar system,” said Tikoo, an assistant professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences. “We really didn’t know the exact physical mechanisms behind how peak ring craters form until this study.”

    For more information, please contact science communicator Todd B. Bates at tbates@ucm.rutgers.edu or 848-932-0550.

    See the full article here .

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    Rutgers, The State University of New Jersey, is a leading national research university and the state’s preeminent, comprehensive public institution of higher education. Rutgers is dedicated to teaching that meets the highest standards of excellence; to conducting research that breaks new ground; and to providing services, solutions, and clinical care that help individuals and the local, national, and global communities where they live.

    Founded in 1766, Rutgers teaches across the full educational spectrum: preschool to precollege; undergraduate to graduate; postdoctoral fellowships to residencies; and continuing education for professional and personal advancement.

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  • richardmitnick 8:29 am on October 31, 2016 Permalink | Reply
    Tags: Asteroids, , , NASA's New 'Intruder Alert' System Spots An Incoming Asteroid   

    From NPR: “NASA’s New ‘Intruder Alert’ System Spots An Incoming Asteroid” 

    NPR

    National Public Radio (NPR)

    October 30, 2016
    Joe Palca

    1

    Asteroids regularly pass by Earth, as depicted here. A new NASA system called Scout aims to identify the ones that will come closest to the planet.
    P. Carril/ESA

    A large space rock is going to come fairly close to Earth later tonight. Fortunately, it’s not going to hit Earth, something astronomers are sure of thanks in part to a new tool NASA is developing for detecting potentially dangerous asteroids.

    The tool is a computer program called Scout, and it’s being tested at NASA Jet Propulsion Laboratory in Pasadena, Calif. Think of Scout as a celestial intruder alert system. It’s constantly scanning data from telescopes to see if there are any reports of so-called Near Earth Objects. If it finds one, it makes a quick calculation of whether Earth is at risk, and instructs other telescopes to make follow-up observations to see if any risk is real.

    NASA pays for several telescopes around the planet to scan the skies on a nightly basis, looking for these objects. “The NASA surveys are finding something like at least five asteroids every night,” says astronomer Paul Chodas of JPL.

    But then the trick is to figure out which new objects might hit Earth.

    “When a telescope first finds a moving object, all you know is it’s just a dot, moving on the sky,” says Chodas. “You have no information about how far away it is. “The more telescopes you get pointed at an object, the more data you get, and the more you’re sure you are how big it is and which way it’s headed. But sometimes you don’t have a lot of time to make those observations.

    “Objects can come close to the Earth shortly after discovery, sometimes one day, two days, even hours in some cases,” says JPL’s Davide Farnocchia. “The main goal of Scout is to speed up the confirmation process.”

    The rock whizzing past Earth tonight was discovered on the night of Oct. 25-26 by the NASA-funded Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) on Maui, Hawaii. Within a few hours, preliminary details about the object appeared on a Web page maintained by the Minor Planet Center at the Smithsonian Astrophysical Observatory. Scout did a quick analysis of the preliminary details and determined that the object was headed for Earth but would miss us by about 310,000 miles.


    Pannstars telescope, U Hawaii, Mauna Kea, Hawaii, USA. A telescope in Hawaii first spotted an errant rock headed toward Earth. The Scout program quickly flagged it for follow-up observations.

    Additional observations by three telescopes, one operated by the Steward Observatory, another called Spacewatch, and a third at the Tenagra Observatories, confirmed the object would miss Earth by a comfortable margin. Astronomers were also able to estimate the size of the object: somewhere between 5 meters and 25 meters across. In case you’re interested, full details about the object’s trajectory can be found here.

    U Arizona Steward Observatory Vatican Advanced Technology Telescope
    U Arizona Steward Observatory Vatican Advanced Technology Telescope

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    Spacewatch

    2
    Tenagra Observatory

    Scout is still in the testing phase. It should become fully operational later this year.

    Now Scout is mainly dealing with smallish, very nearby objects. Complementing Scout is another system that is already operational called Sentry.

    3
    NASA’s Other Asteroid Mission: Grab A Chunk And Put It In Orbit Around The Moon

    4
    Scientists in Michigan have found a new dwarf planet in our solar system. It’s about 330 miles across and some 8.5 billion miles from the sun. It takes 1,100 years to complete one orbit. But one of the most interesting things about the new object, known for the time being as 2014 UZ224, is the way astronomers found it. David Gerdes of the University of Michigan led the team that found the new dwarf planet. Gerdes describes himself as “an adult-onset astronomer,” having started his scientific career as a particle physicist.

    He helped develop a special camera called the Dark Energy Camera that the U.S. Department of Energy commissioned to make a map of distant galaxies.

    Fermilab DECam
    DEam built at FNAL

    The dwarf planet that Gerdes and his colleagues have found isn’t the first distant dwarf planet astronomers have found in recent years. Sedna, Eris and Makemake have all been discovered in the past decade or so. Add to that Pluto, which used to be a planet until it was demoted when the definition changed.

    Sentry’s job is to identify objects large enough to wipe out a major city that might hit Earth in the next hundred years. “Our goal right now is to find 90 percent of the 140-meter asteroids and larger,” says Chodas, but right now he estimates they’re able to find only 25 to 30 percent of the estimated population of objects that size.

    That number should get better when a new telescope being built in Chile called the Large Synoptic Survey Telescope [LSST] comes online. NASA is also considering a space telescope devoted to searching for asteroids.

    LSST/Camera, built at SLAC
    LSST/Camera, built at SLAC

    LSST Interior
    LSST telescope, currently under construction at Cerro Pachón Chile
    LSST telescope, currently under construction at Cerro Pachón Chile

    OK, so let’s say you find one of these monster rocks heading for Earth. What then? Astronomer Ed Lu says there is something you can do. He’s CEO of an organization called B612. It’s devoted to dealing with asteroid threats.

    “If you know well in advance, and by well in advance I mean 10 years, 20 years, 30 years in advance, which is something we can do, ” says Lu, “then you can divert such an asteroid by just giving it a tiny nudge when it’s many billions of miles from hitting the Earth.”

    NASA and the European Space Agency are developing a mission to practice doing just that.

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    ESA/NASA DART

    Lu says in the past decade, people who should worry about such things have begun to make concrete plans for dealing with dangerous asteroids.

    “I believe in the next 10 to 15 years we’ll actually be at the point where we as humans can say, ‘Hey, we’re safe from this danger of large asteroids hitting the Earth,’ ” he says.

    In the meantime, we’ll just have to hope that luck is on our side.

    See the full article here.

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  • richardmitnick 9:44 am on August 5, 2016 Permalink | Reply
    Tags: , Asteroids, ,   

    From AAS NOVA: ” Images of an Activated Asteroid” 

    AASNOVA

    American Astronomical Society

    5 August 2016
    Susanna Kohler

    1
    Graphic (collage) showing relative sizes of possible target asteroids and other known asteroids. ESA

    In late April of this year, asteroid P/2016 G1 (PANSTARRS) was discovered streaking through space, a tail of dust extending behind it. What caused this asteroid’s dust activity?

    2
    Images of asteroid P/2016 G1 at three different times: late April, late May, and mid June. The arrow in the center panel points out an asymmetric feature that can be explained if the asteroid initially ejected material in a single direction, perhaps due to an impact. [Moreno et al. 2016]

    Asteroid or Comet?

    Asteroid P/2016 G1 is an interesting case: though it has the orbital elements of a main-belt asteroid — it orbits at just under three times the Earth–Sun distance, with an eccentricity of e ~ 0.21 — its appearance is closer to that of a comet, with a dust tail extending 20” behind it.

    To better understand the nature and cause of this unusual asteroid’s activity, a team led by Fernando Moreno (Institute of Astrophysics of Andalusia, in Spain) performed deep observations of P/2016 G1 shortly after its discovery. The team used the 10.4-meter Great Canary Telescope to image the asteroid over the span of roughly a month and a half.

    Gran Telescopio  Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain
    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain

    A Closer Look at P/2016 G1

    P/2016 G1 lies in the inner region of the main asteroid belt, so it is unlikely to have any ices that suddenly sublimated, causing the outburst. Instead, Moreno and collaborators suggest that the asteroid’s tail may have been caused by an impact that disrupted the parent body.

    To test this idea, the team used computer simulations to model their observations of P/2016 G1’s dust tail. Based on their models, they demonstrate that the asteroid was likely activated on February 10 2016 — roughly 350 days before it reached perihelion in its orbit — and its activity was a short-duration event, lasting only ~24 days. The team’s models indicate that over these 24 days, the asteroid lost around 20 million kilograms of dust, and at its maximum activity level, it was ejecting around 8 kg/s!

    4
    Comparison of the observation from late May (panel a) and two models: one in which the emission is all isotropic (panel b), and one in which the emission is initially directed (panel c). The second model better fits the observations. [Adapted from Moreno et al. 2016]

    Activation By Impact

    To reproduce the observed asymmetric features in the asteroid’s tail, Moreno and collaborators show that the ejected material could not have been completely isotropically emitted. Instead, the observations can be reproduced if the material was initially ejected all in the same direction (away from the Sun) at the time of the asteroid’s activation.

    These conclusions support the idea that the asteroid’s parent body was impacted by another object. The initial impact caused a large ejection of material, and the subsequent activity is due to the partial or total disruption of the asteroid as a result of the impact.

    To further test this model for P/2016 G1, the next step is to obtain higher-resolution and higher-sensitivity imaging (as could be provided by Hubble) of this unusual object. Such images would allow scientists to search for smaller fragments of the parent body that could remain near the dust tail.

    Citation

    F. Moreno et al 2016 ApJ 826 L22. doi:10.3847/2041-8205/826/2/L22

    See the full article here .

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  • richardmitnick 10:11 am on July 28, 2016 Permalink | Reply
    Tags: Asteroids, , ,   

    From SPACE.com- “Asteroid Defense: Scanning the Sky for Threats From Space” 

    space-dot-com logo

    SPACE.com

    July 28, 2016
    Elizabeth Howell

    1
    This graphic shows all of the potentially hazardous asteroids (and their orbital paths) around Earth (not to scale). As of 2013, scientists had counted over 1,400 of these potentially hazardous asteroids. Credit: NASA/JPL-Caltech

    Earth is hit every day by small bits of space dust. Slightly larger chunks burn up colorfully in the atmosphere, causing the shooting stars you see in the sky. Occasionally even bigger rocks hit our atmosphere; they are known as fireballs, because the light from them burning up is particularly bright. These tend to smack the Earth a few times a year and may produce a few fragments for rock-hunters to find.

    NASA and other organizations do regular scans of the sky to catalog any small bodies that are at risk of crashing into our planet. No imminently threatening bodies have been found yet, but it’s clear that sooner or later Earth will be struck by something big. The organizations are actively researching the best ways to protect Earth from asteroids, meteoroids or comets that may come crashing down.

    Asteroids refer principally to small, rocky bodies. Comets contain more ice and can also pose a threat to Earth. Before fragments enter our atmosphere, they are known as meteroids. During their path in the atmosphere, they are called meteors. If any of these pieces reach the ground, those pieces are called meteorites. The best hunting ground on Earth for meteorites is Antarctica because the ice makes it so easy to see the fragments, and the ground is not disturbed as much as a typical urban area or forest.

    The difference between a meteroid and an asteroid is a little vague. In 1961, The International Astronomical Union (the official body for naming objects in space) said a meteroid is much smaller than an asteroid, but bigger than an atom. A 2010 Meteoritics and Planetary Science paper led by Alan Rubin, a geophysicist at the University of California, Los Angeles, suggested that the limit for meteoroids be about 1 meter in size.

    Characterizing the threat

    It is clear that even small bodies can pose a threat; the asteroid that broke up over Chelyabinsk, Russia, in 2013 was roughly 56 feet (17 meters) across, shattering glass and injuring hundreds of people. In 1908, an estimated 130-foot (40-meter) object exploded over Siberia and flattened trees over 825 square miles (2,137 square kilometers). Around 50,000 years ago, before human civilization began, a rock about 150 feet wide (46 meters) smacked into what is now called Arizona. It left behind Meteor Crater, which is roughly 0.7 miles (1.2 kilometers) wide today.

    1

    Even bigger collisions happened far in the past. The dinosaurs were wiped out 66 million years ago by an object about 6 miles (10 km) wide, which left behind a 110-mile (180 km) crater in Mexico known as Chicxulub. But that’s nothing compared to evidence of another impactor found in 2014. A rock formation in our planet’s crust pointed to a possible impactor 23 to 36 miles (37 to 58 kilometers) across that smacked into Earth 3.26 billion years ago, just a few million years after life evolved.

    NASA began tracking near-Earth objects (NEOs) in the 1970s. Its goal is to find objects that are at least tens of meters in size, “which could cause significant harm to populated areas on the Earth if they were to strike without warning,” NASA stated in 2014.

    Congress directed NASA in 1994 to find at least 90 percent of potentially hazardous NEOs larger than 0.62 miles (1 kilometer) in diameter, which NASA fulfilled in 2010. Congress also asked NASA in 2005 to find at least 90 percent of potentially hazardous NEOs that are 460 feet (140 meters) in size or larger. That’s supposed to be finished by 2020. NASA created a Planetary Defense Coordination Office in 2014 — a year after Chelyabinsk — to better coordinate its efforts, in response to an Office of the Inspector General report. Other space agencies such as the European Space Agency also have their own offices, and the different nations regularly collaborate with each other.

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    An artist’s concept for the Asteroid Impact & Deflection Assessment (AIDA) mission led by the European Space Agency to intentionally strike an asteroid and test deflection capabilities that could protect Earth.
    Credit: ESA

    Scanning the sky

    NASA works with several sky surveys to maintain a list of potentially hazardous objects. These include the Catalina Sky Survey (University of Arizona), Pan-STARRS (University of Hawaii), Lincoln Near-Earth Asteroid Research or LINEAR (Massachussetts Institute of Technology) and Spacewatch (University of Arizona). These observatories are constantly upgrading their capabilities to try to catch fainter asteroids.

    Asteroids are also observed from space by several telescopes, but the one most regularly used for NEO searches is called NEOWISE.

    NASA/WISE Telescope
    NASA/WISE Telescope

    It’s the new mission of the Wide-field Infrared Survey Explorer (WISE) telescope, which launched in 2009 and was revived from hibernation in 2013 to search for asteroids. The telescope is expected to keep operating until 2017, when the angle from the sun in its orbit will be too bright to search for asteroids. A follow-up mission called Near Earth Object Camera (NEOCam) has been proposed for 2021, but is competing against five other missions for funding. Mission selection will be announced in September 2016.

    It’s the new mission of the Wide-field Infrared Survey Explorer (WISE) telescope, which launched in 2009 and was revived from hibernation in 2013 to search for asteroids. The telescope is expected to keep operating until 2017, when the angle from the sun in its orbit will be too bright to search for asteroids. A follow-up mission called Near Earth Object Camera (NEOCam) has been proposed for 2021, but is competing against five other missions for funding. Mission selection will be announced in September 2016.

    There are other NASA missions that are looking to get up close to asteroids to better characterize their composition. Some recent examples: The Dawn mission visited asteroid Vesta between 2011 and 2012, and has now been at Ceres (a dwarf planet) since 2015.

    NASA/Dawn Spacescraft
    NASA/Dawn Spacescraft

    OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is expected to depart for asteroid Bennu in 2018 for a sample-return mission, which will come back to Earth in 2023.

    NASA OSIRIS-Rex Spacecraft
    NASA OSIRIS-REx Spacecraft

    Additionally, NASA uses data available from other space agency missions that visited asteroids, such as the Japanese Hayabusa (completed) and Hayabusa 2 (in progress).

    NAOJ Hayabusa 2
    NAOJ Hayabusa 2

    Some planned missions will take even more daring steps at asteroids. NASA has been working on concepts for an Asteroid Redirect Mission (ARM) that would have a robot move a small body into the moon’s orbit, for astronauts to study. Also: NASA, the European Space Agency and other partners are planning a mission called AIDA, or Asteroid Impact and Deflection Assessment. The goal is to change the path of a small moon orbiting the asteroid Didymos using a kinetic impactor.

    A kinetic impactor (perhaps with a nuclear bomb inside) would deflect the orbit, tugging the asteroid slowly using a spacecraft, redirecting it with solar heat, or blasting it with a laser. That is just one idea. There is ongoing research as to what sort of asteroid deflection technique would be best. The best approach depends on many factors, such as cost, the composition of the asteroid, time to impact and technology maturity. Studies are ongoing in these fields; in 2007, NASA said that non-nuclear kinetic impactors had the most mature technology.

    See the full article here .

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  • richardmitnick 1:05 pm on June 22, 2016 Permalink | Reply
    Tags: , Asteroids, FRIPON   

    From Sky and Telescope: “FRIPON: A New All-Sky Meteor Network” 

    SKY&Telescope bloc

    Sky & Telescope

    June 21, 2016
    David Dickinson

    The innovative FRIPON network will engage professionals and the public in the hunt for space rocks.

    1
    One of the FRIPON all-sky cameras stands watch outside the Paris Observatory.FRIPON

    On February 15, 2013, the world awoke to dramatic news as an asteroid roughly 20 meters across exploded over Chelyabinsk, Russia. The asteroid approached Earth unannounced from a sunward direction, and weeks went by before researchers could analyze all the dash-cam footage, determine the rock’s trajectory, and recover debris from the surviving meteorite.

    Now, imagine a network of all-sky observing sentinels that speeds this whole process up to just days or even hours.

    That’s the goal of the Fireball Recovery and InterPlanetary Observation Network (FRIPON). A collaboration between the Observatory of Paris, the National Center of Scientific Research (CNRS), the University of Paris-South, the French National Museum of Natural History, and the Aix-Marseille University, this network of 100 cameras and 25 radio receivers provides continuous all-sky coverage over all of France. Catching a meteorite’s fall from various angles from known coordinates enables researchers to quickly and accurately determine the location of a possible strewn field for an organized search campaign.

    “If tomorrow a meteorite falls in France, we will be able to know where it comes from and roughly where it landed,” says Jérémie Vaubaillon (Paris Observatory) in a recent Nature.com article.


    Access mp4 video here .

    Sourcing Meteorites

    Most meteors seen in the night sky are just grains of dust, remnants of various comets’ passages, that burn up in our atmosphere without ever hitting the ground. French researchers estimate that 10 meteorites fall in France every year, but a meteor sighting followed by a subsequent meteorite recovery has been a once-a-decade affair. The rolling countryside of France isn’t exactly prime real estate for meteorite hunting — ancient stones from space stand out better against the sands of the Sahara or the pristine ice shelf of Antarctica.

    Now, FRIPON will give French meteorite hunters an edge, enabling them to recover meteorites before the space rocks are lost to erosion and earthly contamination.

    With FRIPON researchers hope to accomplish a ground recovery within 24 hours of a bolide sighting. To accomplish this, the cameras are placed 50 to 100 kilometers apart, many of them at educational and research facilities throughout France.


    Calculating a meteorite’s trajectory requires at least two images from two different stations. Additional stations can help get a clearer view during inclement weather. Even if the trajectory is initially well known, wind can strongly affect the location of the strewn field. Estimating the location becomes more complicated when the meteorite burns out, going dark before it falls. FRIPON

    You can see a searchable map of the FRIPON network, including two cameras based on Corsica, a French island in the Mediterranean sea, and one each in Vienna, Austria, and Bucharest, Romania.

    Researchers hope to expand the FRIPON network into Germany, Switzerland, the Netherlands, and other European countries in the coming years. Other networks are already operating in Europe, including the United Kingdom Monitoring Network (UKMON) and the Spanish Meteor Network. NASA also has its own network in the United States named the All-Sky Fireball Network, with three clusters of cameras across the U.S.

    In addition to aiding recovery, FRIPON will document the trajectory and direction of a meteorite’s fall, allowing researchers to estimate its final orbit and, perhaps, its source.

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    Researchers with a FRIPON camera mounted atop the Natural History Museum in Vienna, Austria. FRIPON

    FRIPON is the first high-density, fully automated meteor observation system connected over a single network, says principle investigator François Colas (Paris Observatory). Other networks, such as one based in Australia, cover a larger area but with a more spread out cameras. Also, while most networks connect cameras that are privately owned and on separate networks, FRIPON’s central computer can look at the same detection from several different cameras on the same network. That means it can quickly estimate a meteorite’s strewn field down to a rectangular box that’s about 1 kilometer by 10 kilometers.

    It will be possible to get very fresh material with the least possible alteration due to our atmosphere,” says Colas. “The goal is to get the meteorite within 24 hours. This is also really new compared to other networks.”
    Expanding the Hunt

    Although only trained scientists will scout for meteorites initially, FRIPON hopes to invite the public to the hunt with the Vigie Ciel (“Sky Watch”) project. This will allow educators and amateur meteor hunters to gain access to FRIPON data so citizen and professional teams can quickly scour the countryside.

    French history is littered with tales of meteorites and meteorite falls. A stony meteorite fell near the town of Ensisheim in the Alsace region on November 7, 1492, and is now on display in the town’s small museum. Another meteorite fall on April 26, 1803, showered 3,000 fragments over the small town of L’Aigle. That find ended the controversy as to whether meteorites were of volcanic or extraterrestrial origin, and it gave rise to the science of meteoritics.

    Strangely, the number of meteorites recovered from France in the 20th century was about one per decade, a drop from one every two years in the 19th century. FRIPON may reverse this trend in the 21st century. So far FRIPON hasn’t resulted in a ground recovery yet, but it has already resulted in a few preliminary orbital calculations, and the project is continuing to mature.

    “In the end, we want to connect a meteorite with a parent body,” says Colas. “We are ready to search for meteorites!”

    See the full article here .

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    Sky & Telescope magazine, founded in 1941 by Charles A. Federer Jr. and Helen Spence Federer, has the largest, most experienced staff of any astronomy magazine in the world. Its editors are virtually all amateur or professional astronomers, and every one has built a telescope, written a book, done original research, developed a new product, or otherwise distinguished him or herself.

    Sky & Telescope magazine, now in its eighth decade, came about because of some happy accidents. Its earliest known ancestor was a four-page bulletin called The Amateur Astronomer, which was begun in 1929 by the Amateur Astronomers Association in New York City. Then, in 1935, the American Museum of Natural History opened its Hayden Planetarium and began to issue a monthly bulletin that became a full-size magazine called The Sky within a year. Under the editorship of Hans Christian Adamson, The Sky featured large illustrations and articles from astronomers all over the globe. It immediately absorbed The Amateur Astronomer.

    Despite initial success, by 1939 the planetarium found itself unable to continue financial support of The Sky. Charles A. Federer, who would become the dominant force behind Sky & Telescope, was then working as a lecturer at the planetarium. He was asked to take over publishing The Sky. Federer agreed and started an independent publishing corporation in New York.

    “Our first issue came out in January 1940,” he noted. “We dropped from 32 to 24 pages, used cheaper quality paper…but editorially we further defined the departments and tried to squeeze as much information as possible between the covers.” Federer was The Sky’s editor, and his wife, Helen, served as managing editor. In that January 1940 issue, they stated their goal: “We shall try to make the magazine meet the needs of amateur astronomy, so that amateur astronomers will come to regard it as essential to their pursuit, and professionals to consider it a worthwhile medium in which to bring their work before the public.”

     
  • richardmitnick 7:07 am on June 1, 2016 Permalink | Reply
    Tags: Asteroids, , , , Water on the Earth's moon.   

    From COSMOS: “Asteroids, not comets, delivered most water to the Moon” 

    Cosmos Magazine bloc

    COSMOS

    1 Jun 2016
    Belinda Smith

    ‘Dirty snowballs’ ferried less than 20% of lunar water – carbonaceous chondrites did the bulk of the work.

    The lion’s share of the Moon’s water was ferried on asteroids – not comets – during its early history, new calculations suggest.

    European and US researchers, led by Jessica Barnes from Open University in the UK, compared atomic differences in molecules from lunar samples to those in comets and asteroids and concluded at least 80% of the Moon’s water came from asteroids called carbonaceous chondrites.

    They published their work in Nature Communications [link does not work].

    Today a grey calm satellite, the Moon’s youth was turbulent. It’s thought to have formed around 4.5 billion years ago when a Mars-sized object slammed into Earth.

    Initially a ball of magma, after a few thousand years it developed a crust – called a thermal lid – which kept any volatiles such as water locked inside. Over the next 200 million years or so, the Moon slowly solidified completely.

    During that time, it was ripe to absorb any comets or asteroids that punched through the crust, along with any water on board. Today, lunar samples show around 100 parts per million water.

    Comets are often described as “dirty snowballs” so one might assume most of the Moon’s water might come from them. But a particular type of asteroid – carbonaceous chondrites – also happens to be particularly water-rich.

    To figure out where the Moon’s water came from – comets or asteroids – Barnes and her colleagues examined hydrogen isotopes in water.

    2
    Potential origins of the Moon’s water, delivered while it was still partially molten.

    Sometimes a hydrogen atom, which comprises one proton, one neutron and one electron, will sometimes accommodate a second neutron. This “heavy water” is found in comets, but not in asteroids.

    Analyses of lunar rock samples show they don’t contain much in the way of heavy water either. Barnes and colleagues calculated that 80% of the Moon’s water was brought on carbonaceous chondrite asteroids while less than 20% came on comets.

    Based on nitrogen isotopes in the Moon, they calculated the specific type of asteroid that probably carried the most water was what’s called a CO-type carbonaceous chondrite. The Ornans meteorite that fell in France in 1868 is one such CO-type.

    Could water have been present in the hot disc of material from which the Moon coagulated, 4.5 billion years ago? Until its crust formed, water would have boiled and hissed out of the Moon’s magma oceans into space.

    But even if the newborn Moon contained 25% of today’s water, asteroids still would have supplied most of the shortfall, the researchers calculated.

    The work doesn’t just apply to the Moon. Mars’ water is remarkably similar to that on early Earth and the Moon, they write, so the same types of asteroid likely “delivered a vast majority of water to the rocky planets in the inner Solar System”

    *Science paper:
    Not available

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  • richardmitnick 6:34 am on May 17, 2016 Permalink | Reply
    Tags: , Asteroids, , Remains of giant asteroid found in outback Australia   

    From COSMOS: “Remains of giant asteroid found in outback Australia” 

    Cosmos Magazine bloc

    COSMOS

    17 May 2016
    Viviane Richter

    Scientists say asteroid could have been 40 kilometres across and would have left a crater hundreds of kilometres wide.

    1
    Chert in Marble Bar, Australia. The remains of the asteroid was found between two volcanic layers of this rock. Credit: DIRK WIERSMA/Getty Images
    ______________________________
    The remains of a giant asteroid that smashed into Earth 3.46 billion years ago have been discovered in north-western Australia.

    Scientists say the asteroid was up to 40 kilometres wide – amongst the largest to have collided with our planet – and its impact could have significantly changed how the Earth’s crust evolved during its youth.

    The remnants of this asteroid come in the shape of tiny glass beads called spherules, which the scientists say formed from material vapourised by the impact.

    These spherules were discovered in Western Australia’s Marble Bar, in samples of sedimentary rock which once formed a sea floor. Because the rock layer in which they were found was wedged between two volcanic layers, the team was able to date the glass beads to 3.46 billion years ago.

    And when the scientists analysed the chemical composition of the rims of the spherules, they discovered elements such as iron, magnesium and nickel matched the levels found in asteroids.

    As the second oldest known to have plummeted into Earth in its youth, this asteroid “is just the tip of the iceberg,” said author Andrew Glikson from the Australian National University. “We’ve only found evidence for 17 impacts older than 2.5 billion years, but there could have been hundreds.”

    Glikson said the crater this asteroid created would have been wiped out by tectonic movement and volcanic activity, which leaves the location of where it impacted unknown.

    2
    A microscopy image of the tiny glass beads called spherules that are all that is left of the asteroid. Credit: Andrew Glikson
    ______________________________

    But the scientists estimated the size of the asteroid based on a previously published model – a linear relationship between spherule size and the size of an impacting object.

    The authors state the two-millimetre spherules, each barely larger than a pinhead, was likely formed by an impacting asteroid as large as 40 kilometres in diameter.

    The crater left behind by such an asteroid would, in turn, have spanned hundreds of kilometres, Glikson said.

    “The impact would have triggered earthquakes orders of magnitude greater than terrestrial earthquakes, it would have caused huge tsunamis and would have made cliffs crumble,” he said.

    “Asteroid strikes this big result in major tectonic shifts and extensive magma flows,” Glikson added. “They could have significantly affected the way the Earth evolved.”

    The discovery was published [link to science paper] in the journal Precambrian Research,
    A new ∼3.46 Ga asteroid impact ejecta unit at Marble Bar, Pilbara Craton, Western Australia: A petrological, microprobe and laser ablation ICPMS study

    See the full article here .

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  • richardmitnick 8:33 pm on April 5, 2016 Permalink | Reply
    Tags: Asteroids, , , ,   

    From JPL: “Asteroid-Hunting Spacecraft Delivers a Second Year of Data” 

    NASA JPL Banner

    JPL-Caltech

    April 5, 2016
    DC Agle
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-9011
    agle@jpl.nasa.gov

    Dwayne Brown
    NASA Headquarters, Washington
    202-358-1726
    dwayne.c.brown@nasa.gov

    1
    This graphic shows asteroids and comets observed by NASA’s Near-Earth Object Wide-field Survey Explorer (NEOWISE) mission. Image credit: NASA/JPL-Caltech/UCLA/JHU

    NASA’s Near-Earth Object Wide-field Survey Explorer (NEOWISE) mission has released its second year of survey data. The spacecraft has now characterized a total of 439 NEOs since the mission was re-started in December 2013. Of these, 72 were new discoveries.

    NASA/NEOWISE
    NASA/NEOWISE

    Near-Earth Objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of the giant planets in our solar system into orbits that allow them to enter Earth’s neighborhood. Eight of the objects discovered in the past year have been classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth.

    DOWNLOAD VIDEO Two Years of NEOWISE Asteroid Data


    Access mp4 video here .

    With the release to the public of its second year of data, NASA’s NEOWISE spacecraft completed another milestone in its mission to discover, track and characterize the asteroids and comets that approach closest to Earth.

    Since beginning its survey in December 2013, NEOWISE has measured more than 19,000 asteroids and comets at infrared wavelengths. More than 5.1 million infrared images of the sky were collected in the last year. A new movie, based on the data collected, depicts asteroids and comets observed so far by NEOWISE.

    “By studying the distribution of lighter- and darker-colored material, NEOWISE data give us a better understanding of the origins of the NEOs, originating from either different parts of the main asteroid belt between Mars and Jupiter or the icier comet populations,” said James Bauer, the mission’s deputy principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, California.

    Originally called the Wide-field Infrared Survey Explorer (WISE), the spacecraft was launched in December 2009. It was placed in hibernation in 2011 after its primary mission was completed. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission: to assist NASA’s efforts to identify the population of potentially hazardous near-Earth objects. NEOWISE also is characterizing previously known asteroids and comets to provide information about their sizes and compositions.

    “NEOWISE discovers large, dark, near-Earth objects, complementing our network of ground-based telescopes operating at visible-light wavelengths. On average, these objects are many hundreds of meters across,” said Amy Mainzer of JPL, NEOWISE principal investigator. NEOWISE has discovered 250 new objects since its restart, including 72 near-Earth objects and four new comets.

    NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the NEOWISE mission for NASA’s Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

    For more information about NEOWISE, visit:

    http://www.nasa.gov/neowise

    More information about asteroids and near-Earth objects is at:

    http://www.jpl.nasa.gov/asteroidwatch

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 10:17 am on December 17, 2015 Permalink | Reply
    Tags: Asteroids, , , ,   

    From Goddard: “International Instrument Delivered for NASA’s 2016 Asteroid Sample Return Mission” 

    NASA Goddard Banner
    Goddard Space Flight Center

    Dec. 17, 2015
    Nancy Neal Jones
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    301-286-0039
    Nancy.N.Jones@nasa.gov

    1
    The OSIRIS-REx Laser Altimeter (OLA), contributed by the Canadian Space Agency, will create 3-D maps of asteroid Bennu to help the mission team select a sample collection site. NASA’s OSIRIS-REx spacecraft will travel to the near-Earth asteroid Bennu and bring at least a 60-gram (2.1-ounce) sample back to Earth for study. Credits: NASA/Goddard/Debbie McCallum /NASA

    A sophisticated laser-based mapping instrument has arrived at Lockheed Martin Space Systems in Denver for integration onto NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft.

    The OSIRIS-REx Laser Altimeter (OLA), contributed by the Canadian Space Agency (CSA), will create 3-D maps of asteroid Bennu to help the mission team select a sample collection site.

    “The OSIRIS-REx Project has worked very closely with our partner CSA and their contractor MDA to get this critical instrument delivered to the spacecraft contractor’s facility,” said Mike Donnelly, OSIRIS-REx project manager from NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We are very pleased with the performance of the instrument and look forward to its contribution to our mission.”

    OLA is an advanced LIDAR (Light Detecting and Ranging) system that will scan the entire surface of the asteroid to create a highly accurate, 3-D shape model of Bennu. This will provide mission scientists with fundamental data on the asteroid’s shape, topography (distribution of boulders, rocks and other surface features), surface processes and evolution. An accurate shape model will also be an important tool for navigators as they maneuver the OSIRIS-REx spacecraft around the 500-meter-wide (0.3-mile-wide) asteroid. In exchange for providing the OLA instrument, CSA will receive a portion of the returned asteroid sample for study by Canadian scientists.

    “OLA will measure the shape and topography of Bennu to a much higher fidelity and with much greater efficiency than any planetary science mission has achieved,” said Michael Daly, OLA instrument lead at York University, Toronto. “This information is essential to understanding the evolution and current state of the asteroid. It also provides invaluable information in aid of retrieving a sample of Bennu for return to Earth.”

    After launch in September 2016, the OSIRIS-REx spacecraft will travel to the near-Earth asteroid Bennu and bring at least a 60-gram (2.1-ounce) sample back to Earth for study. Scientists expect that Bennu may hold clues to the origin of the solar system and the source of water and organic molecules that may have made their way to Earth. OSIRIS-REx’s investigation will also inform future efforts to develop a mission to mitigate an asteroid impact on Earth, should one be required.

    “The data received from OLA will be key to determining a safe sample site on Bennu,” said Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona, Tucson. “This instrument is a valuable addition to the spacecraft, and I appreciate our Canadian partners’ hard work and contribution to the OSIRIS-REx mission.”

    The laser altimeter was built for CSA by MacDonald, Dettwiler and Associates Ltd. (MDA) and its partner, Optech. OSIRIS-REx is scheduled to ship from Lockheed Martin’s facility to NASA’s Kennedy Space Center, Florida in May 2016, where it will undergo final preparations for launch.

    NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission’s principal investigator at the University of Arizona. Lockheed Martin Space Systems in Denver is building the spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency’s Science Mission Directorate in Washington.

    For more information on OSIRIS-REx visit:

    http://www.nasa.gov/osiris-rex

    and

    http://www.asteroidmission.org

    See the full article here .

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 10:30 am on December 15, 2015 Permalink | Reply
    Tags: Asteroids, , ,   

    From nationalgeographic.com: “Space Rocks Delivered One-Two Punch to Ancient Earth” 

    National Geographic

    National Geographics

    December 15, 2015
    Nadia Drake

    1
    A double asteroid impact in an ancient sea, around 460 million years ago, created two crater remnants near Lockne, Sweden.No image credit

    Scientists link a rare, double impact crater in central Sweden to a 470-million-year-old cataclysm in the asteroid belt.

    Around 470 million years ago, what is now central Sweden was covered in a shallow, ancient sea inhabited by tiny, plankton-like organisms. The placid scene would soon be scarred by one of the largest cataclysms in the last billion years.

    That’s because far away, trouble was brewing. In the main asteroid belt, between Mars and Jupiter, two space rocks were about to collide.

    2
    The inner Solar System, from the Sun to Jupiter. Also includes the asteroid belt (the white donut-shaped cloud), the Hildas (the orange “triangle” just inside the orbit of Jupiter), the Jupiter trojans (green), and the near-Earth asteroids. The group that leads Jupiter are called the “Greeks” and the trailing group are called the “Trojans” (Murray and Dermott, Solar System Dynamics, pg. 107).

    When they slammed together, the collision shattered a 200-kilometer-wide asteroid, sending fragments ricocheting through space—some of which headed right for planet Earth.

    As they traveled through the inner solar system, a portion of these pulverized bits and pieces re-congealed, forming what’s known as a rubble pile asteroid—a type of space object that is exactly what it sounds like. But this rocky swarm wasn’t like most of the others: It had a small, orbiting companion.

    And when that twosome finally plowed into the ancient Swedish sea after a 12-million-year journey, it left a distinctive double crater. Or rather, a double crater that would have been distinctive had the smaller of the two punches not remained hidden until just a few years ago.

    “We are quite convinced that the two craters were formed at the same time,” says Erik Sturkell of the University of Gothenburg, who presented the story Monday at the American Geophysical Union’s annual meeting.

    Double Whammy

    Binary craters aren’t exceptionally common on Earth, even though roughly 15 percent of asteroids in Earth-crossing orbits are thought to have a companion in tow. That’s because “getting two distinct nearby craters that are well dated has been hard to accomplish,” says Bill Bottke of the Southwest Research Institute.

    Today, these two 458-million-year-old craters—Lockne and Målingen—are set amidst forests and farmlands.

    3
    Lockne crater location

    Lockne, the larger of the two, is about 7.5 kilometers across and was created as the rubble pile asteroid collided with Earth. About 16 kilometers away is Målingen, which is just 0.7 kilometers across and made by the smaller companion.

    2
    This double crater on Mars was created by two nearly simultaneous impacts.
    Photograph by NASA/JPL-Caltech/University of Arizona

    Scientists aren’t sure precisely how big the two asteroids were, but they estimate the bigger one was at least 600 meters across, and the smaller was at least 150 meters across. Rubble pile asteroids create craters that are a bit different than the scars left behind by dense, intact impactors.

    “The fragments separate but maintain their trajectory,” Sturkell explains. “The effect on the target area can be compared to that of a shotgun blast rather than a single rifle bullet—a shallow, widespread, but still coherent crater.”

    Cataclysmic Breakup

    The fossilized remains of those hapless, plankton-like organisms helped the team determine how long ago planet Earth had gotten punched.

    But, how did scientists link these craters with that 470-million-year-old cataclysm?

    For starters, the asteroids that gouged these double pockmarks into Earth are a particular type of space rock called an L chondrite—something that is rich in olivine and relatively iron-poor. Sprinkled all over the planet are craters of similar ages, made from the same type of asteroid…and there are too many similarly aged craters, with similar fingerprints, to be explained by normal cratering rates.

    In addition, more than 100 fossilized meteorites have been uncovered from Sweden, China, and Russia. These small, preserved fragments arrived on Earth around the same time, and all except one are L chondrites. What’s more, the fragments bear the signature of an ancient collision that occurred about 470 million years ago—before they barreled into Earth.

    3
    Families of asteroids are created when space rocks collide.
    Illustration by NASA/JPL-Caltech

    The only way that pattern could emerge is if a mishap of cosmic proportions destroyed a parent space rock and sent shrapnel flying through the solar system.

    “It probably went through a supercatastrophic disruption event,” Bottke says, noting that, in addition to the cataclysmic breakup, research suggests the parent asteroid happened to be in a spot where gravitational nudges from Jupiter could efficiently send fragments flying toward Earth.

    “A lot of this material was able to get to Earth very quickly,” he says.

    But not all the fragments left their home: Today, the shards from that collision that still live in the main belt are known as the Gefion family. “There is a lot of cool stuff related to this particular event,” Bottke says. “The question is whether this event had other implications, say for life on Earth.”

    See the full article here .

    Please help promote STEM in your local schools.

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    The National Geographic Society has been inspiring people to care about the planet since 1888. It is one of the largest nonprofit scientific and educational institutions in the world. Its interests include geography, archaeology and natural science, and the promotion of environmental and historical conservation.

     
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