Tagged: Discover Magazine Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 10:45 am on July 13, 2019 Permalink | Reply
    Tags: "What Are Intermediate-Mass Black Holes?", , , , , , , Discover Magazine   

    From Discover Magazine: “What Are Intermediate-Mass Black Holes?” 

    DiscoverMag

    From Discover Magazine

    July 12, 2019
    Jake Parks

    1
    The hunt for intermediate-mass black holes (IMBH) has picked up over recent years, and there are now dozens of promising candidates. This artist’s concept depicts a 2,200 solar mass IMBH suspected to reside in the heart of the globular cluster 47 Tucanae, located some 15,000 light-years from Earth. (Credit: B. Kiziltan/T. Karacan)

    Black holes have long served as fodder for science fiction — and for good reason. These unimaginably dense objects contain so much matter trapped in such a small volume that their gravity prevents even light from escaping their surfaces.

    Although the first prediction of a black hole was made nearly 250 years ago by the English philosopher and clergyman John Michell, the first black hole candidate, Cygnus X-1, wasn’t discovered until 1971. Since then, astronomers have tirelessly chipped away at countless questions related to these once-mythical beasts. But one of the most basic and enduring questions remains: Do they come in all sizes?

    Small and Large, or Small to large?

    Over the past few decades, astronomers have compiled loads of evidence for the existence of black holes at both ends of the mass spectrum. Researchers have uncovered small black holes that weigh just a few to 100 times the mass of the sun, as well as supermassive black holes that can reach billions of times the mass of their star-sized brethren.

    Stellar-mass black holes are thought to form when a relatively massive star dies in spectacular fashion. As the exhausted star burns through its final traces of fuel, its immense gravity causes it to collapse in on itself. If the collapsing star isn’t too big, the infalling material rebounds off the star’s dense core. This causes a supernova explosion, often leaving behind a tiny white dwarf or neutron star. But if the surviving remnant is greater than about three solar masses, not even tightly packed neutrons can prevent the city-sized core from continuing to collapse into a stellar-mass black hole.

    On the other hand, there’s another class of black holes known as supermassive black holes, which serve as the central gravitational anchors of most, if not all, large galaxies. Though supermassive black holes are anywhere from millions to billions of times the mass of the sun, they pack all that matter into a region roughly the size of a single star. There are many lines of evidence that indicate these cosmic behemoths are common throughout the universe, but exactly how and when they formed still remains a mystery.

    But what about the in-betweeners? Shouldn’t there should be a class of mid-sized black holes that split the difference between stellar-mass and supermassive black holes? These cosmic middleweights, which would range from about 100 to 1 million solar masses — though the specific range varies depending on who you ask — are referred to as intermediate-mass black holes (IMBHs). And although astronomers have found several compelling IMBH candidates spread throughout the universe, the jury is still out on whether they truly exist. However, the evidence is beginning to pile up.

    2
    Located roughly 290 million light-years from Earth, the edge-on spiral galaxy ESO 243-49 is thought to harbor one of the first strong candidates for an intermediate-mass black hole, HLX-1. The black hole (circled) was found near the edge of the galaxy within a cluster of young stars. (Credit: NASA/ESA/S. Farrell (University of Sydney and University of Leicester))

    NASA/ESA Hubble Telescope

    Is Proof Out There?

    Though conclusive proof of IMBHs remains elusive, over the past few decades, there have been a number of studies that have uncovered intriguing evidence hinting at the existence of these not-so-big, not-so-small black holes.

    For example, in 2003, researchers used the ESA’s XMM-Newton space observatory to identify two strong, distinct X-rays sources in the nearby starburst galaxy NGC 1313. Because black holes tend to ferociously gobble up material that gets too close and belch out high-energy radiation, they are some of the strongest known emitters of X-rays. And by pinpointing NGC 1313’s X-ray sources and studying how they periodically flash, in 2015, researchers were able to constrain the mass of one of the galaxy’s suspected black holes, known as NGC 1313 X-1 [The Astrophysical Journal Letters]. They calculated it’s about 5,000 times the mass of the Sun, give or take about 1,000 solar masses, which would put it firmly in the mass range of an intermediate-mass black hole.

    Likewise, in 2009, researchers uncovered even stronger evidence for the existence of a medium-sized black hole [Nature] . Located some 290 million light-years away near the edge of the galaxy ESO 243-49, the team observed an incredibly bright X-ray source called HLX-1 (Hyper-Luminous X-ray source 1) [Astronomy] that did not have an optical counterpart. This suggests the object is not simply a star or background galaxy. Additionally, the researchers found HLX-1’s X-ray signature varied with time, suggesting a black hole is brightening every time a nearby star makes a close approach, feeding gas to the black hole and causing brief outbursts of X-rays that then slowly fade away. Based on the brightness of the observed flashes, the researchers calculated a minimum mass of the black hole of about 500 times the mass of the Sun, though some estimates put its weight closer to 20,000 solar masses [The Astrophysical Letters].

    “Such a detection is essential,” said lead author Sean Farrell of the University of Leicester after the discovery [ScienceDaily]. “While it is already known that stellar-mass black holes are the remnants of massive stars, the formation mechanisms of supermassive black holes are still unknown.” Farrell went on to explain that “the identification of HLX-1 is therefore an important step towards a better understanding of the formation of the supermassive black holes that exist at the center of the Milky Way and other galaxies.

    More recently, astronomers have started to uncover strong evidence of wandering intermediate-mass black holes lurking near the heart of the Milky Way. For example, in January 2019, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to trace streams of gas orbiting an invisible object, thought to be an IMBH [The Astrophysical Journal Letters] , with an apparent mass of about 32,000 times the mass of the Sun.

    Located a scant 23 light-years from the Milky Way’s supermassive black hole, Sagittarius A*, the discovery suggests the newfound IMBH could merge with the roughly 4-million-solar-mass Sagittarius A* in the not-too-distant future. To help bolster the case for IMBHs wandering through the Milky Way, the researchers hope to use other oddly-orbiting gas clouds to probe our galaxy for more mid-sized black holes tucked away in gas-dominated regions.

    3
    So far, the LIGO and Virgo gravitational-wave detectors have teamed up to uncover 20 stellar-mass black holes in the process of merging to form black holes ranging from about 20 to 80 solar masses. Although LIGO-Virgo has not uncovered any IMBHs (over 100 solar masses), researchers are optimistic about spotting them in the future. (Credit: LIGO-Virgo/Frank Elavsky/Northwestern)

    The Hunt for IMBHs

    Moving forward, researchers will rely on a variety of methods to uncover a slew of more mid-sized black holes. By doing so, they not only hope to prove that IMBHs truly exist, but more importantly, they want to use IMBHs to help piece together how large black holes grow and evolve over time.

    Fortunately, astronomers are now in a prime position to do just that. Thanks to the recent successes of the LIGO-Virgo gravitational-wave project — which has identified 20 stellar-mass black holes [MPIGP] by probing the universe for gravitational waves that are produced when black holes merge — researchers have a new method for searching for small to mid-sized black holes.

    Although the LIGO-Virgo collaboration has yet to uncover gravitational waves from mergers between black holes larger than about 40 solar masses, according to the LIGO website [https://www.ligo.org/science/Publication-O1O2IMBH/index.php], “in [the] future, with improvement in [the] sensitivity of gravitational wave detector[s], we will have a better understanding of the frequency of IMBH mergers. The third observing run has started collecting data from April 1, 2019, and gravitational-wave scientists are very hopeful to observe these elusive sources soon!”

    So stay tuned, because over the next few years, we may find definitive proof of the missing link between small and super-sized black holes. And if we do, it will finally put this cosmic conundrum to rest once and for all. Only then will we be able to stop debating the existence of IMBHs, and instead focus on unraveling their origin stories, as well as those of supermassive black holes.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 9:12 am on July 12, 2019 Permalink | Reply
    Tags: , , , , Discover Magazine, ,   

    From Discover Magazine: “Japanese Asteroid Mission Touches Down on Ryugu, Collects Sample” 

    DiscoverMag

    July 11, 2019
    Korey Haynes

    1
    Hayabusa2 has successfully collected its second sample from the surface of asteroid Ryugu. (Credit: Illustration by Akihiro Ikeshita (C), JAXA)

    Hayabusa2’s encounters with asteroid Ryugu have been delightfully action-packed. In February, the Japanese spacecraft collected its first sample by swooping close and firing a bullet into the asteroid’s surface to stir up material it then snagged with a horn-shaped collector. Then, in April, it shot a much larger impactor into Ryugu, creating an artificial crater so it could examine the material churned up from beneath the surface. On Thursday, Hayabusa2 returned to the scene of the crime and fired a second bullet, collecting material from its newly made crater.

    Astronomers hadn’t been certain they’d be able to find a safe spot to touch down in the new crater, and spent the last few months scouting the area and analyzing the images Hayabusa2 sent back. The successful collection of this second sample means the mission has accomplished all its major goals, and can head back to Earth later this year on a positive note.

    Hayabusa2 is just one spacecraft currently surveying an asteroid with the goal of bringing back pieces of its rocky partner. A NASA mission called OSIRIS-REx is similarly investigating the asteroid Bennu.

    NASA OSIRIS-REx Spacecraft

    Astronomers often find fragments of asteroids in the form of meteorites that fall to Earth, but obtaining samples directly from space gives them a clearer picture of where and how these space rocks formed and how they’ve spent the past few billion years of solar system history.

    The mission team behind Hayabusa2 has had to work hard to get their spacecraft to finish the job it started when it launched back in 2014. Its asteroid, Ryugu, proved more jagged and rocky than mission planners had anticipated. The spacecraft must descend all the way to the surface to collect its samples, and it’s not built to handle rough or uneven terrain. The engineering team found that to guarantee a safe touchdown, they had to dramatically increase the accuracy of their touchdown targeting.

    That took longer than they’d planned, and the craft has a schedule to keep. Its mission timeline has it leaving Ryugu in December so it can bring its samples back to Earth for study. It’s also a race against time, as Ryugu’s surface is about to become too warm for Hayabusa2 to handle, meaning it couldn’t just extend its stay indefinitely.

    But the engineering team persevered, and Hayabusa2 has now successfully completed all its main mission objectives. It still has a few months of work left to do in orbit around Ryugu, taking pictures and measurements from afar, before it can return to Earth with its prized samples.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 11:49 am on July 10, 2019 Permalink | Reply
    Tags: Chandrayaan-2 lunar mission, Discover Magazine, ISRO-Indian Space Research Organisation, Studying the moon’s little explored south pole   

    From Discover Magazine: “India Set to Launch Moon Rover and Orbiter” 

    DiscoverMag

    From Discover Magazine

    July 9, 2019
    Hailey Rose McLaughlin

    1
    (Credit: ISRO)

    India is expected to launch their second lunar mission, Chandrayaan-2 on July 14. The launch will take up an orbiter, a lander, and a rover, dubbed Pragyan, all designed to study the moon’s little explored south pole.

    Using the Indian Space Research Organization’s (ISRO) most powerful rocket, Chandrayaan-2 will reach Earth’s orbit, where it’ll spend about 16 days before it heads over to the moon.

    After a short time in lunar orbit, the lander and the rover will attempt to touch down on the moon’s surface around September 6 or 7, if all goes as planned.

    For about 14 days, the rover will explore this rarely studied lunar area, collecting samples and performing experiments. Meanwhile, Chandrayaan-2’s orbiter is expected to remain operational for about a year, sending back information about the moon to ISRO.

    The new data should help offer insights into moon’s origin, as well as Earth’s own history. And along the way, the Indian space agency also says it will test new technologies that could be used in future deep space travel.

    During ISRO’s first lunar mission a decade ago, their Chandrayaan-1 orbiter mapped the Moon’s surface for some 300 days. It also smashed an instrument called the Moon Impact Probe into the surface, turning up traces of water.

    If this second mission’s soft landing goes as planned, India will be just the fourth country to gently touch down on the moon, joining Russia, the U.S. and China.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 3:03 pm on July 5, 2019 Permalink | Reply
    Tags: California Earthquake, Discover Magazine,   

    From Discover Magazine: “Italian Eruption Turns Deadly and California Rocked by Earthquake” 

    DiscoverMag

    From Discover Magazine

    July 5, 2019
    Erik Klemetti

    1
    Stromboli erupting on July 3, 2019. Image by Anil Charley/Twitter.

    There is the strong tendency in humans to look for patterns, even when none exist. This is amplified by the modern effect of news media, where certain events make headlines for reasons not necessarily related to the severity of the event.

    We see this frequently in geology, where a news-making eruption or earthquake then starts a cascade of reports of other eruptions and earthquakes that follow, even if they aren’t disasters. This feeds into our propensity to construct patterns from things, even when one doesn’d necessarily exist. For example, when read about a bunch of geological events, it’s tempting to think: “Uh oh, the Earth must be getting more active!”

    The truth is that earthquake and eruption activity does wax and wane, but over time, our planet is not “becoming more restless” than it was 100 or 1,000 or 10,000 years ago. Most earthquakes and eruptions are sprinkled randomly over time and that randomness sometimes produces clusters of events. Flip a coin 100 times and you might get 8 heads in a row, then none for another 10 tosses. That’s clustering in a random distribution.

    Over the last few weeks, it might have felt like the Earth was behaving differently. We’ve had big eruptions at Raikoke, Ulawun, Manam. We’ve had earthquakes felt in across the globe: 14 over M6 on the Richter scale in the past 30 days. Yet, in an average year, these things happen. They might not happen in a span of a fortnight, but then again, sometimes they do.

    People’s perceptions of eruptions can be skewed as well. The eruptions at Raikoke, Ulawun and Manam were all big. They produced some of the tallest ash plumes we’ve seen in a few years, reaching over 12-15 kilometers high (>30,000 feet). They were clearly newsworthy events, especially in the case of the two eruptions on Papua New Guinea, where tens of thousands of people live near the volcanoes.

    Luckily, for all three of those giant blasts, it appears that no one was killed. However, another volcano — this time Stromboli in Italy — erupted in an unexpected fashion. The volcano is one of the most active on Earth, so much so that is has been referred to as the “lighthouse of the Mediterranean.”

    Most of its eruptive activity is fairly tame, confined to small explosions at the summit. This means that lots of tourists like to visit the tiny volcanic island of Italy’s western shores so that they can see this volcano in action.

    2
    Stromboli erupting. Evening Standard

    There is the strong tendency in humans to look for patterns, even when none exist. This is amplified by the modern effect of news media, where certain events make headlines for reasons not necessarily related to the severity of the event.

    We see this frequently in geology, where a news-making eruption or earthquake then starts a cascade of reports of other eruptions and earthquakes that follow, even if they aren’t disasters. This feeds into our propensity to construct patterns from things, even when one doesn’d necessarily exist. For example, when read about a bunch of geological events, it’s tempting to think: “Uh oh, the Earth must be getting more active!”

    The truth is that earthquake and eruption activity does wax and wane, but over time, our planet is not “becoming more restless” than it was 100 or 1,000 or 10,000 years ago. Most earthquakes and eruptions are sprinkled randomly over time and that randomness sometimes produces clusters of events. Flip a coin 100 times and you might get 8 heads in a row, then none for another 10 tosses. That’s clustering in a random distribution.

    Over the last few weeks, it might have felt like the Earth was behaving differently. We’ve had big eruptions at Raikoke, Ulawun, Manam. We’ve had earthquakes felt in across the globe: 14 over M6 on the Richter scale in the past 30 days. Yet, in an average year, these things happen. They might not happen in a span of a fortnight, but then again, sometimes they do.

    People’s perceptions of eruptions can be skewed as well. The eruptions at Raikoke, Ulawun and Manam were all big. They produced some of the tallest ash plumes we’ve seen in a few years, reaching over 12-15 kilometers high (>30,000 feet). They were clearly newsworthy events, especially in the case of the two eruptions on Papua New Guinea, where tens of thousands of people live near the volcanoes.

    Luckily, for all three of those giant blasts, it appears that no one was killed. However, another volcano — this time Stromboli in Italy — erupted in an unexpected fashion. The volcano is one of the most active on Earth, so much so that is has been referred to as the “lighthouse of the Mediterranean.”

    Most of its eruptive activity is fairly tame, confined to small explosions at the summit. This means that lots of tourists like to visit the tiny volcanic island of Italy’s western shores so that they can see this volcano in action.

    This familiarity with the volcano’s usual activity can cause people to think the volcano is more benign than it truly is. Stromboli can produce more explosive eruptions, sometimes unexpectedly. This is what happened on July 3, when the volcano exploded (see above), sending ash, papilla (larger volcanic fragments) and volcanincn bombs across the island, generating a small pyroclastic flow that headed down the side of the volcano into the ocean (see below).

    Many tourists on the volcano had to immediately seek cover and some even jumped into the sea. The eruptions started fires on the slopes of the volcano as well. Unfortunately, one person was killed due to the flying volcanic debris from the blast, the volcano’s largest since 2007.

    Now, compared to Raikoke, Ulawun and Manam, this eruption was very, very small. The ash plume was only 2 kilometers (~6,500 feet). In the geologic record, the Stromboli eruption would likely quickly be lost because so little material actually came out. Yet, because people crawl over the slopes of the volcano, even a small but powerful blast can capture the world’s attention.

    The same might be said for the earthquake that rattled southern California on the July 4 (see below). This was one of the largest earthquakes in southern California over the past few years. There are dozens of M6+ earthquakes globally each year, but with the proximity of the Ridgecrest earthquake epicenter to Los Angeles, the temblor was felt by many, many people. Is there any link to the earthquake and these eruptions? Not really beyond the fact they all happened on Earth.

    3
    In this image taken from video provided by Ben Hood, a firefighter works to extinguish a fire, Thursday, July 4, 2019, following an earthquake in Ridgecrest, Calif. (Ben Hood via AP)

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 4:27 pm on June 20, 2019 Permalink | Reply
    Tags: , , , , Discover Magazine,   

    From Discover Magazine: “The Event Horizon Telescope’s Possible Next Target? Blazars” 

    DiscoverMag

    From Discover Magazine

    June 20, 2019
    Korey Haynes

    1
    A blazar is an active black hole hurling jets of material directly at Earth. (Credit: NASA/Goddard Space Flight Center/CI Lab)

    The Event Horizon Telescope made history on April 10 when it captured the first image of a supermassive black hole’s event horizon at the heart of galaxy Messier 87.

    2

    While there’s only one other target close enough to image that way – the black hole at the center of our own Milky Way – there are plenty of other targets where EHT’s sharp gaze can still make breakthroughs.

    Astronomers are proposing to use EHT to image the jets of a blazar called PKS 1510-089 more than 4 billion light-years away. A blazar is one of many names for a black hole that is actively consuming material, resulting in high-energy jets shooting out of the top or bottom of the black hole. With a blazar, the jets are pointed almost directly at Earth, making them especially bright.

    This particular blazar is one of the brightest known, and it’s also highly variable, meaning its brightness changes on short time scales. Many blazars vary on the scale of months to days, but PKS 1510-089 varies on the scale of minutes to hours. Scientists think the powerful, variable jets are the result of the black hole twisting magnetic field lines, but they’ve lacked the technology to peer close enough to discern the details — until now.

    Nicholas MacDonald, from Germany’s Max Planck Institute for Radio Astronomy, presented the case for observing PKS 1510-089 with EHT on June 20 at the annual meeting of the Canadian Astronomical Society in Montreal, Quebec, Canada.

    Bright jets

    In 2008, the Fermi Gamma-Ray Telescope launched, opening a new era of exploration of the high-energy universe. “The big discovery of the last decade,” says MacDonald, “was that blazars dominate the gamma-ray sky. These classes of objects are all bright, but [PKS 1510-089] is one of the brightest.”

    That makes it a good target for EHT, which is a network of telescopes spanning the globe, acting together as one giant telescope the size of the planet. MacDonald wants to use EHT plus ALMA, a radio observatory in Chile composed of yet another 66 telescopes networked together. The ALMA array is much smaller in overall size though, spreading out across only between 500 feet and 10 miles, depending on the movable telescopes’ configuration.

    The problem with EHT acting as one telescope the size of the planet is that it’s not actually one telescope. It’s a telescope with massive holes in it, and that makes the data less reliable. Because ALMA is farther south than most of the EHT telescopes, and is composed of a dense cluster of telescopes itself, it can drastically improve EHT’s results by essentially filling in gaps in EHT’s coverage.

    Event Horizon Telescope Array

    Arizona Radio Observatory
    Arizona Radio Observatory/Submillimeter-wave Astronomy (ARO/SMT)

    ESO/APEX
    Atacama Pathfinder EXperiment

    CARMA Array no longer in service
    Combined Array for Research in Millimeter-wave Astronomy (CARMA)

    Atacama Submillimeter Telescope Experiment (ASTE)
    Atacama Submillimeter Telescope Experiment (ASTE)

    Caltech Submillimeter Observatory
    Caltech Submillimeter Observatory (CSO)

    IRAM 30m Radio telescope, on Pico Veleta in the Spanish Sierra Nevada,, Altitude 2,850 m (9,350 ft)


    Institut de Radioastronomie Millimetrique (IRAM) 30m

    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA
    James Clerk Maxwell Telescope interior, Mauna Kea, Hawaii, USA

    Large Millimeter Telescope Alfonso Serrano
    Large Millimeter Telescope Alfonso Serrano

    CfA Submillimeter Array Mauna Kea, Hawaii, USA, Altitude 4,080 m (13,390 ft)

    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array, Chile

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    Future Array/Telescopes

    IRAM NOEMA in the French Alps on the wide and isolated Plateau de Bure at an elevation of 2550 meters, the telescope currently consists of ten antennas, each 15 meters in diameter.interferometer, Located in the French Alpes on the wide and isolated Plateau de Bure at an elevation of 2550 meters

    NSF CfA Greenland telescope


    Greenland Telescope

    ARO 12m Radio Telescope, Kitt Peak National Observatory, Arizona, USA, Altitude 1,914 m (6,280 ft)


    ARO 12m Radio Telescope

    Astronomers ultimately hope to understand what creates the powerful jets they observe, and that means taking the closer look with EHT.

    “The idea is you have a central supermassive black hole, millions of times the mass of the sun,” MacDonald explains. The black hole is not just consuming gas and dust in a whirlpool, but yanking spacetime itself along for the ride. Researchers think the jets are produced when magnetic fields also get caught and twisted up in this motion, launching relativistic beams of charged material. But they don’t know what it looks like in detail.

    D-brief

    « Third Falcon Heavy Launch Set for Next Week A Molecule Long Thought Harmless Plays a Role in Pancreatic Cancer, Could Hint at Cure »
    The Event Horizon Telescope’s Possible Next Target? Blazars
    By Korey Haynes | June 20, 2019 12:30 pm
    1
    flat disk of material with jet shooting out perpindicular
    A blazar is an active black hole hurling jets of material directly at Earth. (Credit: NASA/Goddard Space Flight Center/CI Lab)

    The Event Horizon Telescope made history on April 10 when it captured the first image of a supermassive black hole’s event horizon at the heart of galaxy M87. While there’s only one other target close enough to image that way – the black hole at the center of our own Milky Way – there are plenty of other targets where EHT’s sharp gaze can still make breakthroughs.

    Astronomers are proposing to use EHT to image the jets of a blazar called PKS 1510-089 more than 4 billion light-years away. A blazar is one of many names for a black hole that is actively consuming material, resulting in high-energy jets shooting out of the top or bottom of the black hole. With a blazar, the jets are pointed almost directly at Earth, making them especially bright.

    This particular blazar is one of the brightest known, and it’s also highly variable, meaning its brightness changes on short time scales. Many blazars vary on the scale of months to days, but PKS 1510-089 varies on the scale of minutes to hours. Scientists think the powerful, variable jets are the result of the black hole twisting magnetic field lines, but they’ve lacked the technology to peer close enough to discern the details — until now.

    Nicholas MacDonald, from Germany’s Max Planck Institute for Radio Astronomy, presented the case for observing PKS 1510-089 with EHT on June 20 at the annual meeting of the Canadian Astronomical Society in Montreal, Quebec, Canada.
    Bright jets

    In 2008, the Fermi Gamma-Ray Telescope launched, opening a new era of exploration of the high-energy universe. “The big discovery of the last decade,” says MacDonald, “was that blazars dominate the gamma-ray sky. These classes of objects are all bright, but [PKS 1510-089] is one of the brightest.”

    That makes it a good target for EHT, which is a network of telescopes spanning the globe, acting together as one giant telescope the size of the planet. MacDonald wants to use EHT plus ALMA, a radio observatory in Chile composed of yet another 66 telescopes networked together. The ALMA array is much smaller in overall size though, spreading out across only between 500 feet and 10 miles, depending on the movable telescopes’ configuration.

    The problem with EHT acting as one telescope the size of the planet is that it’s not actually one telescope. It’s a telescope with massive holes in it, and that makes the data less reliable. Because ALMA is farther south than most of the EHT telescopes, and is composed of a dense cluster of telescopes itself, it can drastically improve EHT’s results by essentially filling in gaps in EHT’s coverage.

    Astronomers ultimately hope to understand what creates the powerful jets they observe, and that means taking the closer look with EHT.

    “The idea is you have a central supermassive black hole, millions of times the mass of the sun,” MacDonald explains. The black hole is not just consuming gas and dust in a whirlpool, but yanking spacetime itself along for the ride. Researchers think the jets are produced when magnetic fields also get caught and twisted up in this motion, launching relativistic beams of charged material. But they don’t know what it looks like in detail.

    “Is it highly ordered, or disordered?” MacDonald wonders. The options are that the magnetic field lines are either turbulent and snarled, or, alternatively, highly ordered in a helical structure. Theorists can reproduce the blazar behavior observed by telescopes with either ordered or disordered computer models of the magnetic fields. So they need to look closer to figure out what’s really going on.

    “The big game changer is ALMA,” MacDonald says, and especially ALMA’s cooperation with the other EHT telescopes. “And so we’re able to – for the first time – resolve down to the scales where we can distinguish where the field is ordered or disordered.”

    MacDonald was approved once for these observations, but weather at multiple points around the globe cheated him of his images. He’s trying again, and the observations, if approved, would be taken sometime between October 2019 and September 2020.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 3:21 pm on April 30, 2019 Permalink | Reply
    Tags: "What ‘Rock Tides’ Reveal About Movements of the Earth", , Discover Magazine,   

    From Discover Magazine: “What ‘Rock Tides’ Reveal About Movements of the Earth” 

    DiscoverMag

    From Discover Magazine

    April 30, 2019
    Rebecca Boyle

    1
    Rock formations in the Atacama Desert. (Credit: Phil Whitehouse via Flickr)

    Earth’s interior teems with movement and heat, a characteristic that manifests in memorable fashion as volcanoes and earthquakes. But even Earth’s more seemingly stable solid rocks move, too. Understanding just how rocks respond when they are pushed and pulled by natural forces, such as tectonic activity, or human-caused forces, like hydraulic fracturing, can make mining, construction, natural gas production and other projects safer. It can also improve geological monitoring in fault zones.

    Now, a new technique uses the fingerprints of the moon, sun and surf to pin down rock behavior.

    Rocks feel solid, but their slight imperfections and cracks give them elastic tendencies, which change when the rock is under some sort of external stress, whether from heat or water or the tidal pull of the moon and sun, said Nicholas van der Elst, a seismologist at the U.S. Geological Survey who was not involved in the new work.

    “For the most part, rocks are elastic in that they change shape when you apply force, but they recover completely when the force is removed. There’s also a small amount of squishy deformation, which takes some time to recover,” he said. These shape changes are captured in a measurement called strain, which can give direct information about rock properties like strength and stiffness. But strain is difficult to measure away from Earth’s surface, van der Elst said.

    Scientists can expose small samples to titanic pressure and heat in lab settings or conduct field measurements of induced seismic activity — like mini-quakes set off by explosive charges — but both these approaches have key limitations such as high costs or questions about how well they replicate the natural environment.

    In the new study [no citation], researchers in Germany were able to link rock strain to seismic velocity changes, using a long-term seismometer station. The seismic velocity measurements serve as a proxy for strain, van der Elst said. And instead of having to squeeze the rock themselves, the scientists let the moon and sun do it for them.

    Christoph Sens-Schönfelder of the GFZ German Research Centre for Geosciences in Potsdam and Tom Eulenfeld of the University of Jena in Germany sifted through 11 years of data from a seismic monitoring station in the Atacama Desert of northern Chile. The Patache station rests on a hillcrest along the Pacific coast, less than 2 kilometers from the shore, in an area where nothing grows save for microbes living in salt rock. The only signs of life are occasional lichen flakes and seabird burrows, and distant lights from copper and salt mines sprinkled through the Atacama. The station keeps tabs on seismic activity in an area known for earthquakes. But it can detect more sensitive ambient movements, too.

    As the moon and sun perpetually tug on Earth, the tides slosh water back and forth all over the planet, causing shorelines to shrink or swell. But not only the water moves: Earth’s insides are strained, too. In this way, the tides serve as a controlled deformation experiment, Sens-Schönfelder said.

    He and Eulenfeld analyzed the Patache recordings for seismic echoes — waves that struck the detector, bounced off the surrounding rock, and then hit the detector again. When they plotted the echo patterns, they could see variations related to the pounding of surf from the Pacific Ocean, a couple kilometers away. They also noticed patterns that repeated every day or half day. They realized the half-day oscillations actually represented two signals, corresponding to 12.42 and 12.56 hours. The 12.42-hour period precisely matches the lunar tide, while the longer oscillation matches the elliptical orbit of Earth’s satellite. The elliptic orbit is the same effect that leads to an occasional “supermoon” when the moon is closer to Earth.

    “We were surprised to see the effects of the tides so clearly,” Sens-Schönfelder said. What’s more, the rocks don’t respond instantaneously, meaning the rock takes some time to relax after it is pushed and pulled.

    The researchers also found something unexpected: The sun was producing a greater effect on the rock tides than they thought it would. Though the sun does contribute to Earth’s tides, its pull is greatly outshone by that of the moon — so why would the one-day seismic signal be so strong? The researchers decided it was related to the sun’s warmth, heating the surface during the day, only to disappear at night and allow the surface to cool and contract.

    “The most surprising thing was that we found an interaction between the tidal and thermal effects. They modulate each other and cause distinct peaks in the spectrum,” Sens-Schönfelder said. The researchers are not sure how these two signals are interacting.

    Van der Elst said the rock deformation and relaxation, or “squishiness,” is faster than the timescales of the tides, which makes it a difficult measurement outside of a controlled lab setting. “It’s a real achievement to have measured this rock property in the field with such precision,” he said.

    Sens-Schönfelder said the researchers were able to separate the effects of temperature and tides by looking at the cycles of the sun and moon — “and the fact that the moon does not cause any heating,” he added. “Disentangling both effects from the sun alone would be much more difficult.”

    Still, the results are precise enough that others should be able to perform similar measurements almost anywhere, and use the signals of the moon and the sun to measure the pulse of the Earth.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 8:16 am on April 26, 2019 Permalink | Reply
    Tags: , , , , , Discover Magazine, LIGO Detects Gravitational Waves From Another Neutron Star Merger,   

    From Discover Magazine: “Breaking: LIGO Detects Gravitational Waves From Another Neutron Star Merger” 

    DiscoverMag

    From Discover Magazine

    April 25, 2019

    1
    An artist’s illustration of two colliding neutron stars. (Credit: NASA/Swift/Dana Berry)

    For just the second time, physicists working on the Laser Interferometer Gravitational-Wave Observatory (LIGO) have caught the gravitational waves of two neutron stars colliding to form a black hole.

    The ripples in space time traveled some 500 million light-years and reached the detectors at LIGO, as well as its Italian sister observatory, Virgo, at around 4 a.m. E.T. on Thursday, April 25. Team members say there’s a more than 99 percent chance that the gravitational waves were created from a binary neutron star merger.


    Shot at a Kilonova

    In the moments after the event, a notice went out alerting astronomers around the world to turn their telescopes to the heavens in hopes of catching light from the explosion, which may have formed an extreme object called a kilonova. Kilonovas are 1,000 times brighter than normal novas, and they create huge amounts of heavy elements, like gold and platinum. That brightness makes it easy for astronomers to find these events in the night sky — provided they’ve been given a heads-up and location from LIGO first.

    LIGO’s twin L-shaped observatories — one in Washington state and one in Louisiana — work by shooting a laser beam down the long legs of their “L.”

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Their experimental setup is precise enough that even the minimal disturbance caused by a passing gravitational wave is enough to trigger a slight change in the laser’s appearance. It made the first ever detection of gravitational waves in 2016. Then it followed up by detecting merging neutron stars in 2017.

    Scientists use any slight delays between when signals reach the detectors to help them better triangulate where the waves originated in the sky. But one of LIGO’s twin detectors was offline Thursday when the gravitational wave reached Earth, making it hard for astronomers to triangulate exactly where the signal was coming from. That sent astronomers racing to image as many galaxies as they could across a region covering one-quarter of the sky.

    And instead of finding one potential binary neutron star merger, astronomers turned up at least two different candidates. Now the question is which, if any, are related to the gravitational wave that LIGO saw. Sorting that out will require more observations, which are already happening around the world as darkness falls.

    “I would assume that every observatory in the world is observing this now,” says astronomer Josh Simon of the Carnegie Observatories. “These two candidates (they’ve) found are relatively close to the equator, so they can be seen from both the Northern and Southern Hemisphere.”

    Simon also says that, as of Thursday afternoon in the United States, telescopes in Europe and elsewhere should be gathering spectra on these objects. His fellow astronomers at the Carnegie Observatories plan to turn their telescopes at Chile’s Las Campanas Observatory to the event as soon as darkness falls Thursday night.

    Carnegie 6.5 meter Magellan Baade and Clay Telescopes located at Carnegie’s Las Campanas Observatory, Chile. over 2,500 m (8,200 ft) high

    History-Making Merger

    LIGO’s first detection of a neutron star merger came in August of 2017, when scientists detected gravitational ripples from a collision that occurred about 130 million light years away. Astronomers around the world immediately turned their telescopes to the collision’s location in the sky, allowing them to gather a range of observations from across the electromagnetic spectrum.

    The 2017 detection was the first time an astronomical event had been observed with both light and gravitational waves, ushering in a new era of “multi-messenger astronomy.” The resulting information gave scientists invaluable data on how heavy elements are created, a direct measurement of the expansion of the universe and evidence that gravitational waves travel at the speed of light, among other things.

    This second observation appears to have been slightly too far away for astronomers to get some of of the data they had hoped for, such as how nuclear matter behaves during the intense explosions.

    2
    Researchers at the Laser Interferometer Gravitational-wave Observatory (LIGO) in Livingston, La., recently upgraded the massive instrument. (Ernie Mastroianni/Discover)

    And astronomers still aren’t sure whether the first detection they made came from a typical neutron star merger or whether it was more exotic. But to figure that out, they’d need observations as early as possible, and precious hours have already passed.

    “After the first event, it was clear that a lot of the action was going on immediately after the explosion, so we wanted to get observations as soon as possible,” Simon says. In this case, with one of LIGO’s detectors down, they couldn’t find the object as quickly as they did in 2017.

    So far, one difference is that, unlike last time, astronomers haven’t spotted any signs of gamma-ray bursts, says University of Wisconsin-Milwaukee physicist Jolien Creighton, a LIGO team member.

    But regardless, having additional observations should help us learn more about these extreme cosmic collisions.

    “It gives us a much better handle on the rate of such collisions,” says Stefan Ballmer, associate physics professor at Syracuse University and LIGO member. “The upshot: if we just observe a little longer we will get the strong signal we are hoping for.”

    LIGO just started its third observing run a few weeks ago. And, in the past, these detections were kept a closely guarded secret until they were confirmed, peer-reviewed and published. But with this latest round, LIGO and Virgo have opened their detections up to the public. In this latest run, LIGO has also already detected three potential black hole collisions, bringing its total lifetime haul to 13.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 4:37 pm on April 18, 2019 Permalink | Reply
    Tags: "Tiny Star Flares 10 Times Brighter Than the Sun", , , , , Discover Magazine, ESO Next Generation Transit Survey (NGTS) telescope, The tiny star bears the unwieldly name ULAS J224940.13-011236.9   

    From Discover Magazine: “Tiny Star Flares 10 Times Brighter Than the Sun” 

    DiscoverMag

    From Discover Magazine

    April 18, 2019
    Korey Haynes

    1
    This illustration shows an extremely active, tiny star. (Credit: University of Warwick/Mark Garlick)

    On August 13, 2017, the Next Generation Transit Survey (NGTS) telescope spotted an intense solar flare from a tiny star barely bigger than Jupiter.

    ESO Next Generation Transit Survey, an array of twelve 20-centimetre telescopes at Cerro Paranel, 2,635 metres (8,645 ft) above sea level

    But despite this sun’s diminutive size, the flare gave off as much energy as 80 billion megatons of TNT. That’s 10 times as powerful as the strongest flare ever observed on our own sun. It’s also the coolest star ever observed to give off such a hot flare, and the spectacular outburst is teaching astronomers the power of small stars.

    Light it Up

    The tiny star bears the unwieldly name ULAS J224940.13-011236.9 and sits 250 light-years from Earth. In fact, classified as an L dwarf, it only barely qualifies as a star. “Any lower in mass and it would definitely be a brown dwarf,” said James Jackman, lead author of the discovery paper, in a press release. Brown dwarfs are sub-stars, too big to count as a planet, but too small to sustain the nuclear fusion in their cores that defines a star. Most telescopes, including NGTS, can’t even see dim little ULAS J2249−0112 during normal times. But the flare lit up the star clearly in the data, boosting it to 10,000 times its normal brightness. Jackman and his team published their findings April 17 in the Monthly Notices of the Royal Astronomical Society Letters.

    Because flares last only a few minutes – this one was visible for 9.5 minutes – it takes luck or a special instrument like NGTS, which looks at wide patches of the sky over quick time intervals, to spot such phenomena.

    2
    NASA’s Solar Dynamics Observatory caught an X2.0-class solar flare erupt off our own sun in 2014. (Credit: NASA/SDO)

    NASA/SDO

    Astronomers have spied powerful flares from tiny stars before, but they are rare. In general, smaller stars like this one have fewer, less powerful flares than larger dwarf stars. ULAS J2249−0112 is just the second L-dwarf flare ever seen from the ground and the sixth L-dwarf to be seen flaring at all, and this flare is the brightest yet seen in an ultra-cool star. Astronomers weren’t sure until now that such small, cool stars had enough energy in their chromospheres, or outer layers, to support such powerful flares.

    But the find shows that even tiny stars can pack quite the punch.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 1:14 pm on April 17, 2019 Permalink | Reply
    Tags: "What Is the Most Dangerous Volcanic Hazard?", 1 Pyroclastic Flows (also known as hot ash flows or pyroclastic density currents), 2. Ash Fall, 3. Lahars (also known as volcanic mudflows), 4. Tsunamis, 5. Lava Flows, , Discover Magazine,   

    From Discover Magazine: “What Is the Most Dangerous Volcanic Hazard?” 

    DiscoverMag

    From Discover Magazine

    April 17, 2019
    Erik Klemetti

    1
    The 2015 eruption of Calbuco in Chile, with the city of Puerto Montt in the foreground. Wikimedia Commons.

    Volcanoes can be pretty dangerous. Thankfully, we’ve gotten better over the last half century at getting people out of the way of volcanic hazards. However, many hundreds of millions of people still live close enough to volcanoes to feel the impact of an eruption — especially when the volcano decides to have a spectacular eruption.

    There are a lot of misconceptions out there about what the most dangerous aspects of a volcanic eruption might be. I think many people picture lava flows cascading down the sides of a volcano and imagine that the searing rivers of molten rock are what will do you in.

    Well, they’re right in one respect: stay in the path of a lava flow and you will likely cease being alive. But luckily, lava flows are actually pretty easy to avoid as they move rather slowly, rarely up to ~30 km/hr (20 mph) but more likely less than 8 km/hr (5 mph). You can probably out-walk most lava flows.

    So, what is it that makes volcanoes so deadly if it isn’t the copious volumes of lava they can produce? Here’s a little countdown of what I think are the most dangerous volcanic hazards based on the number of deaths associated with them, the potential for damage to houses and infrastructure, the frequency with which they occur and the difficulty of avoiding them.

    5. Lava Flows: After all that pre-amble about lava flows, here they are! Though lava flows may not cause many fatalities, the potential damage to infrastructure and homes is very high. Lava flows are also very common at certain types of volcanoes, so with that combination of frequency and destructiveness, we need to take lava flows seriously. The 2018 eruption at Kīlauea is a perfect example, where there were no fatalities but over 700 homes destroyed. However, the lava can be deadly in rare cases. This can happen when the composition and temperature of the lava means it is especially runny, so it travels fast. An eruption of Nyiragongo in the Democratic Republic of the Congo produced lava flows that moved through the city of Goma killing dozens.

    2
    Lava flow from the 2018 eruption of Kīlauea in Hawaii. USGS/HVO.

    4. Tsunamis: Tsunamis can be generated by geologic events other than eruptions — in fact, they are more common with earthquakes. However, volcanoes can produce these deadly ocean waves when part of the volcano collapses during an eruption. Most recently, the 2018 eruption of Anak Krakatau killed over 420 people when most of the relatively-small cinder cone collapsed during an eruption. The predecessor to Anak Krakatau — Krakatau itself — generated a massive 30-m tsunami when it collapsed into a caldera in 1883. That eruption and tsunami killed over 35,000 people along the Sunda Strait in Indonesia. Other volcanoes, like Unzen in Japan, have had deadly tsunamis as well.

    3
    Anak Krakatau not long after the 2018 collapse that generated a deadly tsunami. Alex Gerst – ISS/ESA.

    3. Lahars (also known as volcanic mudflows): You might be tempted to think mudflows couldn’t be too deadly, but these rivers of volcanic (and other) debris generated by snow and ice melt during an eruption or heavy precipitation on a volcano are very hazardous. Lahars have the consistency of wet cement and they flow at tens of kilometers per hour down river valleys. Many times, that allows for enough forewarning to escape if you are downriver, but the 1985 eruption of Nevado del Ruiz in Colombia proved that a lack of preparation can lead to over 20,000 deaths. Due to their density, lahars can destroy infrastructure and homes and bury towns (and people) rapidly. They can happen without an eruption, such as when old volcanic debris gets mobilized during heavy rain or snow melt. That’s why volcanoes like Mt. Rainier have lahar warning systems for the towns downslope from the volcano.

    4
    The town of Chaitén buried by lahar deposits from the 2008 eruption of Chaitén in Chile. Flickr.

    2. Ash Fall: It might look like snow, but volcanic ash is nasty. It’s made of tiny pieces of volcanic glass and other debris, so if you can imagine inhaling broken glass, well, you get the idea. It can be carried for potentially thousands of kilometers depending on the size of the eruption and winds. When it piles up, the ash can destroy roofs, contaminate water, annihilate vegetation and even block out the sun. If you are unlucky enough to breathe in the ash, it will coat the inside of your lungs and cut them up, people can die from the silica cement in their lungs and/or from more or less drowning in those fluids. Volcanic ash in the atmosphere can disable jet engines, so flying through even dilute ash clouds is a bad idea. Ash fall can be persistent as well, with a volcano producing ash that might accumulate a few millimeters or centimeters thick for months to years — and as I mentioned with lahars, you can get the ash moving again with heavy rains or even with winds.

    5
    Buildings destroyed by ash fall at Clark Air Base in the Philippines during the 1991 eruption of Pinatubo. USGS.

    1 Pyroclastic Flows (also known as hot ash flows or pyroclastic density currents): If you’re looking for that one-two punch of destruction and potential for major fatalities, it is hard to beat a pyroclastic flow. Imagine a cloud of hot volcanic gases and debris that ranges in size from tiny specks of ash to massive boulders, all moving down a volcano at over 300 km/hr (190 mph) at a temperature over 600ºC. You, your city, everything is toast. Some of the deadliest pyroclastic flows buried Pompeii in 79 A.D., wiped St. Pierre off the map during the 1902 eruption of Pelée, erased towns surrounding El Chichón in Mexico in 1982, snapped enormous trees as they flattened forest at Mount St. Helens in 1980 and buried entire valleys during the 1912 eruption of Novarupta in Alaska and 1991 eruption of Pinatubo. They are landscape-altering events that occur in mere moments. If you don’t get buried in the hot debris, you’ll be sizzled to death in the volcanic gases or choke on the ash.

    6
    Pyroclastic flow from Mount St. Helens in June 1980. USGS.

    Pyroclastic flows are generated a number of ways: a collapsing ash column from an eruption, a collapsing lava dome at the top of a volcano or an explosive eruption that moves sideways. Some recent research on pyroclastic flows suggests that they move so far and fast because they travel on a bed of air like a hovercraft. This allows them to travel tens of kilometers from the volcano and “leap” over obstacles. Even seasoned volcanologists can be caught off guard by unpredictable travel of pyroclastic flows. A 1991 eruption of Unzen killed Maurice and Katja Krafft, famed volcano documentarians, along with USGS volcanologist Harry Glicken. Pyroclastic flows need to be taken seriously because you will not survive being in the path of these clouds of volcanic fury.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 9:21 am on March 31, 2019 Permalink | Reply
    Tags: "Here’s What Scientists Hope to Learn as LIGO Resumes Hunting Gravitational Waves", , , Discover Magazine, , Kagra gravitational wave detector,   

    From Discover Magazine: “Here’s What Scientists Hope to Learn as LIGO Resumes Hunting Gravitational Waves” 

    DiscoverMag

    From Discover Magazine

    March 29, 2019
    Korey Haynes

    After a year of downtime to perform hardware upgrades, the Laser Interferometer Gravitational-Wave Observatory (LIGO) is ready for action and will turn on its twin detectors, one in Washington state and the other in Louisiana, on April 1. This time, it will also be joined by the Virgo collaboration based out of Italy, and possibly also by the KAGRA detector in Japan later in the year.


    VIRGO Gravitational Wave interferometer, near Pisa, Italy


    Caltech/MIT Advanced aLigo Hanford, WA, USA installation


    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger

    Gravity is talking. Lisa will listen. Dialogos of Eide

    ESA/eLISA the future of gravitational wave research

    Localizations of gravitational-wave signals detected by LIGO in 2015 (GW150914, LVT151012, GW151226, GW170104), more recently, by the LIGO-Virgo network (GW170814, GW170817). After Virgo came online in August 2018


    Skymap showing how adding Virgo to LIGO helps in reducing the size of the source-likely region in the sky. (Credit: Giuseppe Greco (Virgo Urbino group)

    Combined with the hardware upgrades, scientists expect these updates to allow LIGO to spot more observations and trace their origins more clearly. In 2016, LIGO made history with the first-ever direct detection of gravitational waves, produced in that case by colliding black holes.

    3
    A wrinkle in space-time confirms Einstein’s gravitation. Credit: Astronomy Magazine

    New Hardware

    “Most of the upgrades have been increasing the amount of laser power that’s used,” says Jolien Creighton, a University of Wisconsin Milwaukee professor and member of the LIGO collaboration. “That’s improved the sensitivity.” Each of LIGO’s detector is a giant L-shape, and instruments wait for passing gravitational waves to distort the length of each arm of the detector, measuring them by bouncing lasers across their lengths. Researchers are also pushing the physical limits of the detector, which Creighton says is limited by the quantum uncertainly principle. To increase sensitivity even more, the experiment will “quantum squeeze” the laser beam. “This puts it into an interesting quantum mechanical state that lets us detect the arm length of the detector,” to even greater precision than before.

    The additional detectors from Virgo and KAGRA will let researchers triangulate sources on the sky more accurately than the two LIGO detectors can manage alone. Virgo will be online throughout the whole next year of observing, while KAGRA is still being commissioned, but could join as early as fall of 2018 [? Don’t ask me, I did not write this].


    KAGRA gravitational wave detector, Kamioka mine in Kamioka-cho, Hida-city, Gifu-prefecture, Japan

    New Detections

    The upgraded LIGO will look for many of the same events it did before: collisions of two black holes, two neutron stars, or mixtures of both. Creighton says he’s personally excited about binary neutron stars, because those systems are the mostly likely to have counterparts that can be observed by traditional observatories at the same time, at wavelengths from radio waves to visible light to gamma rays. “Seeing more of those will give us more insight into the natures of gamma ray bursts and the formation of elements of the universe,” Creighton says. He points out the mergers can also teach astronomers how matter behaves when crunched down denser than an atom’s nucleus, a state that only exists in neutron stars. “The way we can probe that is by watching the interactions of neutron stars just before they merge. It’s a fundamental nuclear physics lab in space.”

    Creighton says he’s confident they’ll see many more events from colliding black holes, a phenomenon LIGO has already observed more than once. “We’re hoping to see a binary of a neutron star and a black hole,” Creighton says, but since no one has ever seen one, it’s hard to calculate how common or rare they are, and what the odds are of LIGO spotting one in the next year. But LIGO will be peering farther into the universe, “so even rare things should start to be observed,” Creighton says.

    Other possible objects LIGO might spy would be a supernova explosion, or an isolated neutron star spinning rapidly. “If it’s not perfectly symmetric, then that rotating distortion would produce gravitational waves,” Creighton says. The signal would be weak but constant, so the longer LIGO looks, the more likely finding a source like this becomes. Even more subtle would be a skywide, low-level reverberation from the Big Bang, similar to the microwave background that exists in radiation, and which researchers suspect might also exist in gravitational waves.

    “There’s always the hope that we’ll see something entirely unexpected,” Creighton adds. “Those are the things that you really can’t predict in any way.”

    LIGO’s upcoming run will last for roughly a year, at which point it will undergo more upgrades for a year, and then hopefully start the cycle over again, prepared to witness even more spectacular and invisible events.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    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: