Tagged: Cosmos Magazine Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 10:09 am on July 19, 2017 Permalink | Reply
    Tags: "Top five places to look for extraterrestrial life, Cosmos Magazine, , , , The moon Titan,   

    From COSMOS: “Top five places to look for extraterrestrial life” 

    Cosmos Magazine bloc

    COSMOS Magazine

    19 July 2017
    Andrew Masterson

    For all the hope and expectation, it is sobering to recall that, despite the best efforts of scientists and engineers, there is still no evidence that life exists anywhere beyond our own planet. There are, however, some planetary prime suspects. Here are the five places astronomers and astrobiologists think are the best chances for harbouring ET.

    1
    An artist’s impression of “rocky super-Earth” LHS 1140b and its red dwarf host. M. Weiss/CfA

    LHS 1140b

    News of this planet, a “rocky super-earth”, was announced in the journal Nature in April. Orbiting a red dwarf 39 light-years from Earth, the planet sits in its star’s habitable zone and has an estimated mass almost seven times that of our own planet, leading to the assumption that it comprises rock encasing a solid iron core. According to Jason Dittmann of the Harvard Smithsonian Centre for Astrophysics in Massachusetts, US, LHS 1140b’s density means it might have survived the runaway global warming thought to denude many red dwarf planets. If so, it might now boast a stable atmosphere and liquid water. “This is the most exciting exoplanet I’ve seen in the past decade,” he said. “We could hardly hope for a better target to perform one of the biggest quests in science – searching for evidence of life beyond Earth.”

    4
    Enceladus Curtains: Comparing Data and Simulation. http://photojournal.jpl.nasa.gov/catalog/PIA19061.

    Enceladus

    Thanks to data from NASA’s Cassini spacecraft, Saturn’s moon Enceladus has emerged as every ET-hunter’s favourite target – mainly due to the strong likelihood that it features a subterranean ocean. In April this year, a team of scientists from the South West Research Institute (SWRI) in Texas, US, revealed a plume of hydrogen erupting from the moon’s surface. The plume may well be evidence of hydrothermal vents in the subsurface ocean – the same type of vents that support extremophile life on earth. “The discovery of hydrogen gas and the evidence for ongoing hydrothermal activity offer a tantalising suggestion that habitable conditions could exist beneath the moon’s icy crust,” says principal investigator Hunter Waite.

    In its final swoop close to the surface of Enceladus, NASA’s Cassini spacecraft has delivered a stunning cliffhanger by detecting the most remarkable hints yet that there may be life on Saturn’s sixth-largest moon.

    That swoop took place in October 2015, but research published this month in Science reveals that the spacecraft – which is due to end its 22-year mission by plunging into the planet’s surface in a few months – detected hydrogen gas in a plume of material erupting from the moon’s surface.

    3
    Hovering over Titan. NASA.

    Titan

    Another of Saturn’s 53 moons, Titan is known to have permanent hydrocarbon lakes, a nitrogen-heavy atmosphere, and possibly a subsurface ocean beneath a salty crust. It is a possible host for either water-dependent or methane-dependent life.

    6

    Proxima-b

    https://cosmos-magazine.imgix.net/file/spina/photo/10883/170628_ProximaB_Full.jpg?fit=clip&w=835
    Artist’s impression of the planet orbiting Proxima Centauri. ESO/M. KORNMESSER / GETTY.

    This planet, discovered in August 2016, orbits the star Proxima Centauri, 4.2 light-years away from our sun, and is the nearest candidate beyond the solar system for hosting ET. Research in May’s Astronomy & Astrophysics journal found the chances of life existing on the planet may hinge on its orbital speed. Astrophysicists at the University of Exeter calculated that if Proxima-b rotates on its axis three times for every two times it orbits its sun, then the chances of it being habitable are substantially improved.

    4
    TRAPPIST-1 planet lineup. NASA.

    The announcement of the Trappist-1 system in February, with seven rocky planets orbiting an ultracool dwarf star, sent ripples of excitement through astrobiologists everywhere. At least three of the planets looked like they were within the star’s habitable zone. The latest analysis, by Eric Wolf from the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, US, has somewhat dampened expectations, suggesting that only one of the group has life-sustaining potential. But never mind: one chance in seven is still better than no chance at all.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 9:59 am on December 15, 2016 Permalink | Reply
    Tags: , , Cosmos Magazine, Protein HER2 a culprit   

    From COSMOS: “How breast cancer spreads before tumours can be detected” 

    Cosmos Magazine bloc

    COSMOS

    15 December 2016
    Anthea Batsakis

    1
    Coloured scanning electron micrograph of a migrating – or metastasising – breast cancer cell. Science Photo Library / Getty Images

    Like a weed spreading seeds before it’s even sprouted from the soil, breast cancer cells can migrate around the body before any lumps can be felt or detected by a mammogram, two mouse studies show.

    Each proposes an explanation why early disseminating cancer cells – cells that “spread” around the body when the tumour is only microscopic – are better at invading distant tissues than those from an advanced tumour.

    Both studies, published in Nature, could lead to new ways of monitoring cancer’s spread.

    “They have such firm support that early dissemination is really occurring much more than we thought,” Rik Thompson, breast cancer biologist from the Queensland University of Technology in Australia and who was not involved in the study, says.

    Metastasis – the formation of secondary tumours as a result of disseminating cells – is responsible for most cancer-related deaths.

    And while the idea that early disseminating cancer cells lead to metastasis is nothing new, the question of why hasn’t yet been fully answered.

    A protein called HER2 is overproduced in roughly 25% of breast cancer cases. In those patients, the chance their cancer will reappear increases three-fold.

    Both teams of researchers investigated HER2-positive cancer but told two different stories.

    Hedayatollah Hosseini from the University of Regensburg in Germany and his colleagues suggest
    [Nature] the female hormone progesterone drives the circulation of early cancer cells from microscopic tumours.

    Meanwhile, Kathryn Harper from the Icahn School of Medicine at Mount Sinai in the US and her colleagues showed [Nature] the HER2 protein itself helped early invasive cells enter the bloodstream.

    Thompson says that neither paper is more convincing than the other – they’re simply different, and challenge the common notion that cancer cells are better at spreading when they originate from an advanced tumour.

    Harper’s team hooked up a microscope to mice mammary glands and watched its cancer cells in the lining tissue. They also studied human bone marrow samples seeded with disseminated cancer cells.

    And they found that HER2 switches on another protein, which in turn subdues a cancer-halting enzyme called p38. The cancer cells were able to circulate the body unhindered.

    On the other hand, Hosseini and colleagues turned to progesterone.

    Using human tissue samples, the researchers showed that progesterone triggers a cell to release two proteins that target and strengthen an invasive cells’ ability to migrate.

    Thompson is curious about a possible connection between the two studies – specifically p38 from Harper’s study and progesterone from Hosseini’s.

    “Clearly they’re both working on the same model on early stage dissemination, but the connection between the two is an intriguing question for me,” he says. Perhaps progesterone regulates p38 – or the other way around.

    And in the short term, the researchers suggest HER2-positive breast cancer patients may benefit from close blood monitoring early on to catch any tumours that might grow from metastasising cells.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 5:00 am on December 9, 2016 Permalink | Reply
    Tags: Cosmos Magazine, Einstein’s Greatest Mistake: The Life of a Flawed Genius" Book Review,   

    From COSMOS: “Einstein’s Greatest Mistake: The Life of a Flawed Genius” Book Review 

    Cosmos Magazine bloc

    COSMOS

    09 December 2016
    Bill Condie

    1
    NON-FICTION
    Einstein’s Greatest Mistake: The Life of a Flawed Genius
    By David Bodanis
    Little, Brown (2016)
    RRP $35.00

    We all make mistakes, for sure, but fallibility is not the first thing that comes to mind when thinking about the most recognisable genius the world has ever produced. David Bodanis, that talented explainer of complex physics to lay readers, whose E=mc2: A Biography of the World’s Most Famous Equation is among the clearest explanations of the famous formula, has come up with a perfect sequel.

    Described by the author as “the story of a fallible genius, but also the story of his mistakes”, the book tries to explain the anticlimactic later years of the great man’s life. Tourists may have still gawped as Einstein trudged home in Princeton, but during those final decades he was largely ignored by working scientists.

    The explanation lies, Bodanis argues, in the same characteristics of imagination and self-confidence that led the young Einstein to change the way we thought about physics forever. As he says, “genius and hubris, triumph and failure, can be inextricable”. To understand where Einstein went wrong, it is necessary to examine his earliest years to understand how his mind engaged with the mysteries of the universe.

    It began with Einstein’s discovery that mass and energy are different forms of the same stuff, expressed in the neat little formula E=mc2 – unheard of at the time, but so dramatically demonstrated as true in the skies over Hiroshima, where a tiny sliver of matter became a knockout blow of energy.

    Later came the theory of general relativity that proved energy and mass distort spacetime. The discovery unified gravity into a single view of the universe, no longer a separate force but the result of existing laws. Laws, Einstein thought, that were very clear and very exact. No wonder he considered the theory “the greatest satisfaction of my life”.

    Ironically though, it was this faith in the perfection of his theory – one could say a blind faith – that closed his mind to other emerging schools of thought, particularly those developing in theories of quantum mechanics. That the quantum world of subatomic particles was a place of inherent uncertainty and contradiction was anathema to Einstein’s belief in the underlying laws that guided his own theory. God, he said, “is not playing at dice”. And that, to Bodanis, was his greatest mistake. It was also a blindness that kept Einstein in the wilderness for the last 25 years of his life.

    With the centenary of Einstein’s general theory of relativity last year, there is no shortage of books about Einstein. But this one is still a welcome addition to the vast library. It comes, as mentioned, with Bodanis’ talent for explaining the maths and science of Einstein’s work. But the best part is the real feel it gives of Einstein the man, and his thinking.

    The poor, somewhat arrogant, student of his youth – whose teachers thought would amount to little thanks to his reluctance to take instruction – against the odds gives birth to the in-his-prime scientist combining wonderful imagination and rigour to shake our understanding of the world to its foundations. But that, in turn, leads to a dogmatism that locks him out of a world of new thought that, had he approached the problem differently, he might have contributed so much to.

    It’s a wonderful exposition of the life of Einstein – the man with the superhuman mind who was, in the end, all too human.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 11:22 am on November 25, 2016 Permalink | Reply
    Tags: , Cosmos Magazine, , Mega-earthquakes strike where fault lines are flat   

    From COSMOS: “Mega-earthquakes strike where fault lines are flat” 

    Cosmos Magazine bloc

    COSMOS

    25 November 2016
    Kate Ravilious

    1
    The flat north section of the subduction zone sliding beneath Japan – the dark blue line near the top of this image – is a prime spot for earthquakes larger than magnitude-9 to strike, new research says. NOAA

    When it comes to giant earthquakes, it’s the smooth, ramp-shaped fault lines you need to watch.

    New work published in Science changes how seismologists understand which parts of the world are capable of producing a mega-quake – magnitude 8.5 or greater – and adds Mexico to the hit list, despite there being no historical evidence of mega-quakes there.

    “This is potentially quite a significant change in our understanding of how thrust faults operate,” says Paul Somerville, a geoscientist at Macquarie University in Sydney, who wasn’t involved in the study.

    Around the rim of the Pacific Ocean, the ocean floor is forced under the continents it meets. It is along this diving tectonic plate, known as a subduction zone, that the world’s largest earthquakes occur.

    The tectonic plates of the world were mapped in 1996, USGS.
    The tectonic plates of the world were mapped in 1996, USGS

    Seismologists assumed that mega-quakes only rattled young, fast-moving subduction zones, but the magnitude-9.3 Indian Ocean earthquake in 2004 (on a slowly moving plate) and the magnitude-9 Tohoku-Oki earthquake in Japan in 2011 (on a relatively old plate) completely overturned this theory.

    Seismologists have since become wary of all subduction faults – and in particular any highly curved, locked regions where stress might build up.

    But was this a fair assumption? Quentin Bletery from the University of Oregon and colleagues in the US and France wanted to find out, so they analysed whether the shape of a fault influenced the size of quake it could produce.

    Using previously gathered seismic data, they calculated the curvature of each segment of fault around the Pacific Rim. They found mega-quakes struck only on relatively flat, smooth-moving sections of fault – a finding supported by their own fault models – not those strongly locked.

    According to the new analysis, faults capable of producing mega-quakes run alongside Indonesia, Japan up to Kamchatka, the Aleutians to Alaska, Cascadia (along the north-west coast of North America), Central America and the entire coast of South America.

    “Our results suggest that giant earthquakes are possible in Java, Peru and Mexico even though we don’t have historic evidence of mega-quakes in these regions,” Bletery says.

    Meanwhile, good news for people living near sections of fault bordering the Solomon Islands, the Philippines, and between Santa Cruz and the Loyalty Islands in the western Pacific.

    “The subduction fault is too highly curved in these locations [for such mega-quakes to strike],” Bletery explains.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 5:10 am on November 23, 2016 Permalink | Reply
    Tags: Cosmos Magazine, , ,   

    From COSMOS: “Gravity shifts could sound early earthquake alarm” 

    Cosmos Magazine bloc

    COSMOS

    23 November 2016
    No writer credit found

    1
    The 2011 Tohoku-Oki earthquake generated tsunamis that devastated large swathes of Japan, including the Fukushima Nuclear Power Plant. A new earthquake detection technique might help give residents a few minutes’ extra warning. XINHUA / Gamma-Rapho / Getty Images

    As deep rock shuffles around, an area’s gravitational pull changes too. Detecting these blips could provide precious minutes when it comes to tsunami warnings.

    Earthquakes can shuffle around huge chunks of the deep Earth. But picking up these signs by measuring the associated transient gravity change might help provide early warnings, new research shows.

    Jean-Paul Montagner from the Paris Institute of Earth Physics in France and colleagues examined data collected during the devastating 2011 Tohoku-Oki earthquake off the coast of Japan, and detected a distinct gravity signal that arose before the arrival of the seismic waves. They published their work in Nature Communications.

    And while the technology to employ their system is not yet set up, they say the technique may herald new developments in early warning systems for earthquake hazards such as tsunamis.

    Earthquakes are notoriously hard to predict. When a fault line ruptures, seismic waves travel through and around the Earth and these are usually the first sign that at earthquake has hit.

    And even though these waves travel quickly – the fastest, P-wave or primary waves, can barrel through the Earth at 13 kilometres per second – they still mean precious seconds or minutes before the waves arrive at a seismic station.

    Montagner and his crew thought there could be a way to detect an earthquake before the waves appeared.

    Seismologists have known for more than a decade that there are static gravity changes following a rupture. This happens because as a fault line moves around, mass is redistributed below the surface. This means some areas suddenly become less dense while others pack on mass – and so their gravitational pull changes too.

    Such changes are measured with gravimeters. The problem is there’s background noise when it comes to gravity changes – the dynamic Earth constantly shifts and wriggles. Could the sudden gravity signal associated with an earthquake be teased out from the underlying noise?

    To find out, the researchers needed to examine a large earthquake that happened close enough to a sensitive gravimeter, so small changes in the gravity field could be picked up, but far enough away so the P-waves didn’t immediately reach seismic sensors.

    They found an ideal example in the 11 March Tohoku-Oki earthquake that led to the Fukushima Nuclear Power Plant disaster.

    Some 500 kilometres from the earthquake’s epicentre was a gravimeter at the Kamioka Observatory. The observatory was surrounded by five seismic stations. P-waves from the earthquake took around 65 seconds to reach the stations.

    Montagner and his colleagues first “calibrated” their statistical technique with 60 days of background gravity measurements – from 1 March 2011 to 5.46am on 11 March (21 seconds before the earthquake rumbled), then from 12 March to 30 April.

    They compared this background with measurements taken during the earthquake and shortly thereafter, and found a distinct blip at the time of the earthquake. It was small, but strong enough to be distinguished from the background with 99% confidence.

    So can this prediction technique be implemented today? Unfortunately not – it would require building a substantial network of exceptionally sensitive gravimeters which don’t yet exist. But, the researchers write, they could have the potential to let seismologists estimate earthquake magnitude quickly – a process that currently takes up to several minutes.

    See the full article here .

    You, too, can help with earthquake knowledge and research.

    QCN bloc

    Quake-Catcher Network

    The Quake-Catcher Network is a collaborative initiative for developing the world’s largest, low-cost strong-motion seismic network by utilizing sensors in and attached to internet-connected computers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes, give early warning to schools, emergency response systems, and others. The Quake-Catcher Network also provides educational software designed to help teach about earthquakes and earthquake hazards.

    After almost eight years at Stanford, and a year at CalTech, the QCN project is moving to the University of Southern California Dept. of Earth Sciences. QCN will be sponsored by the Incorporated Research Institutions for Seismology (IRIS) and the Southern California Earthquake Center (SCEC).

    The Quake-Catcher Network is a distributed computing network that links volunteer hosted computers into a real-time motion sensing network. QCN is one of many scientific computing projects that runs on the world-renowned distributed computing platform Berkeley Open Infrastructure for Network Computing (BOINC).

    BOINCLarge

    BOINC WallPaper

    The volunteer computers monitor vibrational sensors called MEMS accelerometers, and digitally transmit “triggers” to QCN’s servers whenever strong new motions are observed. QCN’s servers sift through these signals, and determine which ones represent earthquakes, and which ones represent cultural noise (like doors slamming, or trucks driving by).

    There are two categories of sensors used by QCN: 1) internal mobile device sensors, and 2) external USB sensors.

    Mobile Devices: MEMS sensors are often included in laptops, games, cell phones, and other electronic devices for hardware protection, navigation, and game control. When these devices are still and connected to QCN, QCN software monitors the internal accelerometer for strong new shaking. Unfortunately, these devices are rarely secured to the floor, so they may bounce around when a large earthquake occurs. While this is less than ideal for characterizing the regional ground shaking, many such sensors can still provide useful information about earthquake locations and magnitudes.

    USB Sensors: MEMS sensors can be mounted to the floor and connected to a desktop computer via a USB cable. These sensors have several advantages over mobile device sensors. 1) By mounting them to the floor, they measure more reliable shaking than mobile devices. 2) These sensors typically have lower noise and better resolution of 3D motion. 3) Desktops are often left on and do not move. 4) The USB sensor is physically removed from the game, phone, or laptop, so human interaction with the device doesn’t reduce the sensors’ performance. 5) USB sensors can be aligned to North, so we know what direction the horizontal “X” and “Y” axes correspond to.

    If you are a science teacher at a K-12 school, please apply for a free USB sensor and accompanying QCN software. QCN has been able to purchase sensors to donate to schools in need. If you are interested in donating to the program or requesting a sensor, click here.

    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing, developed at UC Berkeley.

    Earthquake safety is a responsibility shared by billions worldwide. The Quake-Catcher Network (QCN) provides software so that individuals can join together to improve earthquake monitoring, earthquake awareness, and the science of earthquakes. The Quake-Catcher Network (QCN) links existing networked laptops and desktops in hopes to form the worlds largest strong-motion seismic network.

    Below, the QCN Quake Catcher Network map
    QCN Quake Catcher Network map

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 12:01 pm on November 21, 2016 Permalink | Reply
    Tags: , , , Cosmos Magazine, Vela Supercluster   

    From COSMOS: “Galactic supercluster found hiding behind Milky Way” 

    Cosmos Magazine bloc

    COSMOS

    1
    The centre of the image, so-called the Zone of Avoidance, is covered by the Milky Way (with its stellar fields and dust layers shown in grey scale), which obscures all structures behind it. The larger ellipse labelled VSC shows the distribution of galaxies in and around the Vela supercluster. Vela may be similar in aggregate mass to the Shapley Concentration (SC, smaller ellipse), although much more extended. Thomas Jarrett (UCT)

    The Zone of Avoidance. It sounds like a no-fly zone, but it’s actually a swathe of the sky rendered invisible to astronomers, thanks to the Milky Way galaxy’s dust and stars in the way.

    But now, astronomers from South Africa, Europe and Australia, led by Renee Kraan-Korteweg from the University of Cape Town, have discovered a giant collection of galaxies – called the Vela Supercluster – concealed by the Milky Way, some 800 million light-years away.

    The so-called Vela supercluster was unveiled in the Monthly Notices of the Royal Astronomical Society Letters.

    Superclusters are the biggest and most massive known structures in the universe. The can stretch hundreds of millions of light-years end to end.

    The most famous, the Shapley Supercluster, is thought to be the largest of its kind in our corner of the cosmos. It’s around 650 million light-years away.

    Now another, though more distant, supercluster has been seen – sort of. Kraan-Korteweg and her crew examined thousands of galaxies partly within the Zone of Avoidance (that is, partially masked by the Milky Way) with the Southern African Large Telescope in 2012.

    They found eight new clusters in the area of the Vela constellation. Observations with the Anglo-Australian Telescope measured their redshift to track their movements – and it turned out they were all part of the one supercluster.

    Looking up in the sky, with the Milky Way a streak overhead, the Vela Supercluster would look perpendicular behind it, if it were visible.

    “I could not believe such a major structure would pop up so prominently,” Kraan-Korteweg says.

    Follow-up observations will uncover the supercluster’s extent, mass and gravitational influence. New telescopes and surveys, such as the MeerKAT in South Africa, which saw first light this year, and the Taipan galaxy survey in Australia will help out.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 9:29 am on November 8, 2016 Permalink | Reply
    Tags: , , Cosmos Magazine, Scraps of brightest exploding stars stretch over time,   

    From COSMOS: “Scraps of brightest exploding stars stretch over time” 

    Cosmos Magazine bloc

    COSMOS

    08 November 2016
    Belinda Smith

    The inner layer of a superluminous supernovae has elongated in a matter of weeks, new observations show.

    1
    RCW 103, the remains of a supernova explosion located about 9,000 light-years from Earth. It’s nothing compared to superluminous supernovae, though – and a new study suggests the big ones have a couple of ejecta layers. X-ray: NASA / CXC / University of Amsterdam / N.Rea et al; Optical: DSS

    Some of the biggest and brightest exploding stars don’t keep a spherical shape, new observations show, but may periodically stretch into a hot dog bun shape.

    Cosimo Inserra from Queen’s University Belfast in the UK and colleagues measured polarised light, which gives information about asymmetries of the source, emanating from the superluminous supernova 2015bn. They found it changed shape over the course of a couple of months, pulling from a ball into an ellipsoid after peak brightness.

    The work, published in The Astrophysical Journal, provides another insight into the lifecycle of these strange cosmic objects.

    Supernovae are produced when a star in its death throes and collapses on itself, blasting a shell of material away from a black hole or a dense, spinning object with an immense magnetic field called a magnetar left in the centre.

    Superluminous supernovae, as their name suggests, are particularly bright – but they’re mysterious.

    While they explode with billions of times the energy of the sun – and last longer than a typical supernova, stretching months instead of weeks – astronomers have only known of their existence for the past six years or so.

    One of the closest superluminous supernovae – SN 2015bn – is fading in visible light, but undulating in the ultraviolet part of the spectrum. This, astronomers think, is the result of a magnetar reheating material around it, which results in a burst of ejecta every 30 to 50 days.

    But while it was ramping up to peak brightness, Cosimo and his colleagues trained a spectrograph on Chile’s Very Large Telescope on SN 2015bn to detect polarised light.

    ESO/VLT at Cerro Paranal, Chile
    ESO/VLT at Cerro Paranal, Chile

    Where unpolarised light waves move in, say, horizontal and vertical planes, polarised light moves in a single plane. Measuring polarised light – called polarimetry – and analysing it with come nifty calculations can give astronomers the rough shape of an object, such as the layers of supernova ejecta.

    The best fitting model comprised two layers of ejecta. Some 24 days before peak brightness, SN 2015bn’s outside ejecta layer was the same shape as the inner – like a soccer ball inside a basketball.

    But 28 days after the brightness started waning, more polarised light intimated that the inner ejecta had morphed into an ellipsoid while the outer later stayed roughly spherical – like a small rounded Australian football in a basketball.

    So what does this mean?

    The axisymmetric shape, the researchers write, is in line with a core-collapse explosion. A central inner engine of a magnetar or black hole pumps energy into the layers, causing the asymmetry over time.

    As to whether the shape is typical for a superluminous supernova or not is unknown. More observations and detailed modelling of other superluminous supernovae – and time – will tell.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 12:14 pm on October 21, 2016 Permalink | Reply
    Tags: , Cosmos Magazine, , Magnitude-7.1 Kumamoto earthquake, Mt Aso in Japan,   

    From COSMOS- “Japanese volcano interrupted an earthquake: study” 

    Cosmos Magazine bloc

    COSMOS

    21 October 2016
    Amy Middleton

    It looks like Mt Aso’s magma chamber stifled part of the magnitude-7.1 Kumamoto earthquake in April, but that stress might boost its activity, seismologists warn.

    1
    The largest active volcano in Japan, Mount Aso, may have put stopped a 7.1-magnitude earthquake in its tracks. STR / AFP / Getty Images

    When an earthquake tore down a fault line in Japan in April this year, its destructive course may have been halted early thanks to a crater beneath a nearby volcano.

    A day after the magnitude-7.1 Kumamoto earthquake struck Kyushu Island in southwest Japan, Japanese seismologists, led by Aiming Lin of Kyoto University, headed into the field to investigate its passage.

    According to their paper published in Science today, the quake had torn through 40 kilometres of earth along the Hinagu–Futagawa Fault Zone, as well as a series of newly discovered faults, in close proximity to nearby Mt Aso – one of the world’s largest active volcanoes.

    Although experts know there’s a relationship between volcano and earthquake activity, it’s a tricky interaction to study because examples don’t come up too often.

    The proximity of this quake to Mt Aso presented a rare opportunity.

    The researchers identified new faultlines cut into a 380-kilometre-wide crater that forms part of Mt Aso. Interestingly, the rupture that cut into the volcanic crater – also known as a caldera – terminated suddenly.

    The cause of this interruption, the researchers suggest, was the magma chamber under the volcanic crater around three kilometres beneath the Aso caldera.

    At the depth of the magma chamber, around six kilometres below the crater, the quake’s ruptures ceased, probably because the magma chamber’s extreme temperature (around 580 °C) sent the seismic pressure upwards instead of continuing its path.

    “Magma is fluid so it absorbs stress,” says Lin.

    “That’s why the damage – the co-seismic rupturing – shouldn’t travel any further.”

    This change in pressure direction created a new series of stress fields beneath the active volcano.

    Importantly, the researchers suggest the new ruptures under the caldera could potentially trigger an eruption of Mt Aso in the near future and they urge experts keep a close eye on its activity.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 8:41 am on October 14, 2016 Permalink | Reply
    Tags: , , Cosmos Magazine, , Microtektites, Signs of comet collision found in 5.5-million-year-old rocks, Spherules   

    From COSMOS: “Signs of comet collision found in 5.5-million-year-old rocks” 

    Cosmos Magazine bloc

    COSMOS

    14 October 2016
    Amy Middleton

    1
    Glass blobs in rocks found along the US east coast point to a comet collision a few million years ago. Marc Ward / Stocktrek Images / Getty Images

    Glassy spheres discovered in sedimentary rock have tipped off geologists about a previously unknown prehistoric comet crash – one that may have triggered a period of intense global warming.

    Morgan Schaller at the Rensselaer Polytechnic Institute in New York and colleagues found marble-like glassy spherules, known as microtektites, which they believe to be fragments of debris scattered into the air after an object collided with the Earth some 5.5 million years ago.

    They published their work in Science.

    2
    Examples of a few of the spherules examined in the study. M F Schaller et al, Science 2016

    The distinct structures and unique appearances of spherules, as well as the way they’re positioned in sediment, can offer clues about historic impact events.

    Schaller’s spherules were found in marine shelf sites on the Atlantic Coastal Plain, along the east coast of the US, dating back to the boundary between the Paleocene and Eocene epochs.

    This is known as the Paleocene-Eocene Thermal Maximum (PETM), one of the most dramatic climate events known to science.

    During this period, the global average temperature was 8 °C higher than it is today and the world largely devoid of ice. Massive amounts of carbon were injected into the atmosphere and oceans and many of the world’s organisms experienced drastic shifts in their evolution.

    This intense warming is particularly relevant to us, because it marks the closest comparative event to the global warming evident today.

    What may have kick-started the PETM is hotly debated, and theories stretch from volcanic degassing to the cycle of Earth’s orbit. Now, the possibility of a meteorite impact may be thrown into the mix.

    To draw clues from the spherules, the researchers analysed the size, structure, layout and abundance of the particles they had uncovered, and compared the data to evidence of other impact sites.

    Shape and colour of the fragments also offered clues about their origins.

    “The spherules often have surface pits and in some cases microcraters,” the researchers write, “indicating relative velocities high enough to fracture the spherules on impact with one another, or other objects, after solidification.”

    Not everyone’s convinced, though.

    Christian Koeberl, an impact specialist at the University of Vienna in Austria, said the spherules could have come from another time and been reworked into the PETM sediments.

    The researchers did not directly use radiometric dating on the spherules themselves – just the surrounding sediment.

    But the next step, according to the research team, is to uncover spherules in more locations and start to figure out how far the debris spread. This will help them eventually narrow down a potential crater location to mark the comet’s impact.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 11:16 am on September 13, 2016 Permalink | Reply
    Tags: , Cosmos Magazine, , How tides may tip small earthquakes into monsters   

    From COSMOS: “How tides may tip small earthquakes into monsters” 

    Cosmos Magazine bloc

    COSMOS

    13 September 2016
    Belinda Smith

    1
    The 2004 Indian Ocean tsunami, triggered by a massive undersea quake, tossed boats and debris across Indonesia and surrounding islands. New research suggests the moon and sun may have had something to do with the earthquake’s intensity.
    Jim Holmes / Getty Images

    The three biggest earthquakes of recent years struck at a full or new moon, new research shows, when the moon’s tidal tug on the Earth was particularly strong.

    A trio of seismologists from Japan measured tidal stresses – the amount the Earth’s crust bulges and shifts, depending on the moon’s effect – and found large earthquakes are more likely to be triggered during a spring tide.

    Interestingly, there was almost no effect on small earthquakes. But the work, published in Nature Geoscience, could help pinpoint danger times when large earthquakes are more likely to strike.

    Each day, myriad small earthquakes rattle the crust. Every now and again, one will bloom into a massive rupture capable of toppling entire cities and killing thousands of people.

    How these large earthquakes evolve is still a mystery – and how the moon is involved, even more so.

    We’re familiar with the moon’s effect on the oceans – tides rise and fall twice a day. The sun, too, plays a role in our tides.

    While it’s more a supporting role, when the moon and sun line up, their combined efforts produce an even bigger tide – which we know as the spring tide.

    This celestial pull also affects the Earth’s crust. This is called tidal stress. But studies trying to find a link between tides and earthquakes has yielded mixed results.

    A 2004 paper found earthquakes of magnitude 7.0 or above tended to occur more frequently during spring tides, but it was a tendency that couldn’t be supported statistically – and when smaller earthquakes were included, the trend disappeared altogether.

    But the amplitude or size of the tidal stress isn’t the same from spring tide to spring tide.

    So Satoshi Ide, Suguru Yabe and Yoshiyuki Tanaka from the University of Tokyo calculated tidal stress amplitude for the two weeks before the three most recent large earthquakes: the 2004 Indian Ocean earthquake which had a magnitude more than 9.0, the magnitude-8.8 Chile quake in 2010, and the 2011, magnitude-9.0 earthquake off the coast of Tohoku-Oki, Japan.

    The first two occurred near a full moon, close to the maximum amplitude of tidal stress.

    The Japanese earthquake, though, happened at a neap tide, or the tidal phase with the least difference between high and low water. But the trio’s calculations showed tidal stresses were still very high at the time.

    Smaller earthquakes didn’t show the same trend, although the authors note regional variation.

    For instance, earthquakes around magnitude 5 in northeastern Japan did seem to be controlled, to a degree, by tidal stress.

    So what’s happening?

    No one knows for sure. Some seismologists think deep tectonic tremors at plate boundaries could be particularly sensitive to tidal stress changes.

    They plate boundaries don’t lurch in an instant – they tend to take days of slow slipping before a big quake. And in those days, a small change in tidal stress might be enough to tip it over the edge from a small earthquake to a monster.

    Knowing the tidal stress state in such regions can’t predict when a quake will strike, but it might be used to improve earthquake forecasting, the researchers write – particularly the extreme events.

    During periods of high tidal stress, the probability that a magnitude-5 earthquake will grow to a magnitude-9 rises by a factor of six when compared to low stress conditions.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: