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  • richardmitnick 2:48 pm on November 13, 2019 Permalink | Reply
    Tags: "How to Peer Through a Wormhole", Andrea Ghez Keck/UCLA Galactic Center Group, , , , , Dennis Overbye, For now the door is closed. Wormholes might exist and we might never reliably detect them., , Star S0-2   

    From The New York Times: “How to Peer Through a Wormhole” 

    New York Times

    From The New York Times

    Nov. 13, 2019
    Dennis Overbye

    Theoretically, the universe may be riddled with tunnels through space and time. Two scientists have now proposed a way to detect the existence of a cosmic escape hatch.

    Chad Hagen

    Want to get away? Far away? There is a way. Maybe.

    In science fiction, wormholes — tunnels through space and time — have long been the preferred means of travel across the universe. In the movie Interstellar, directed by Christopher Nolan in collaboration with Kip Thorne, the physicist and Nobel laureate at the California Institute of Technology, astronauts venture through a wormhole from our solar system to another galaxy to explore potential replacement planets for a worn-out Earth.

    So I was intrigued when a pair of physicists suggested recently that it might be possible to determine if there is a cosmic subway station at the center of our own galaxy. That is where a supermassive black hole — an invisible cosmic tombstone four million times more massive than the sun — lurks, wreathed in mystery and imagination behind the dusty clouds of Sagittarius.

    Wormholes are another prediction of Einstein’s theory of general relativity, which has already delivered such wonders as an expanding universe and black holes, objects so dense they swallow light. One simple version of a wormhole, called an Einstein-Rosen bridge, consists of a pair of black holes stuck back-to-back, each facing out into its own realm of the universe or universes and connected by a “throat” — the wormhole.

    But nobody knows if wormholes actually exist. If wormholes did exist, they wouldn’t let you go anywhere or even send a message. The moment you tried, the wormhole would crinkle up and crush you.

    To prevent a wormhole from imploding, it would have to be filled with an exotic substance, sometimes called phantom energy, that exerted negative gravity. But most scientists think the laws of physics forbid such a substance.

    “To get a stable, traversable wormhole, you need some magic,” said Dejan Stojkovic, a physicist at the University at Buffalo and a co-author of a recent paper on the topic [Physical Review D].

    But for theorists who believe in magic, there are millions of ways to design a wormhole, Dr. Thorne said in an email. “Since we know nothing firm about the technologies and materials available to a very advanced civilization, we physicists have an infinity of freedom in building models for traversable wormholes,” he wrote.

    In their paper, published Oct. 10 in Physical Review D, Dr. Stojkovic and De-Chang Dai, of Yangzhou University in China, envisaged a layer of this exotic phantom energy packed around the entrance to the Sagittarius black hole, wedging open a wormhole through which you could safely pass. As a sufficiently small object approached the hole, and just before it reached the event horizon, the point of no gravitational return, it would suddenly find itself in another time and place, perhaps in another universe.

    The authors proposed that their thought experiment offered a way to test if wormholes actually exist. Even if the wormhole was too small for a star or a spaceship to traverse, gravity could reach through, they contend.

    “Gravity is just a property of space-time itself, so if you shake one end of it, you will feel it on the other end too,” Dr. Stojkovic explained in a series of email exchanges.

    So a star on one side of a wormhole might feel a gravitational tug from a star or other massive object on the other side of the wormhole. To astronomers, strange deviations in one star’s trajectory could indicate the influence of a “ghost star” reaching through the wormhole from the far side.

    The region around the supermassive black hole at the center of the Milky Way, known as Sagittarius A*.Credit… NASA/CXC/Univ. of Wisconsin/Y.Bai, et al.

    Dr. Dai and his colleague have a particular star in mind to test the idea: a blue star known as S2, or sometimes S02, that tightly circles the Sagittarius black hole, approaching to within 11 billion miles every 16 years.

    Star S0-2 Andrea Ghez Keck/UCLA Galactic Center Group at SGR A*, the supermassive black hole at the center of the milky way

    Astronomers [Andrea Ghez Keck/UCLA Galactic Center Group] have been following the star for years to gain clues about Einstein’s theory of gravity and the inner workings of the black hole. But they might be able to see deeper.

    Imagine that the Milky Way black hole, known officially as Sagittarius A* (pronounced “A-star”), harbored such a wormhole, Dr. Dai and Dr. Stojkovic wrote in the paper. Presumably, the gravity of stars or other massive objects on the far side could leak through the wormhole and tug S2 slightly off its orbit.

    With a few more years of study, they noted, astronomers should know S2’s orbit precisely enough to detect such a tug, which would accelerate the star about one millionth of a meter per second per second. Astronomers could also look for similar effects near other known black holes.

    “This would be spectacular if observed,” Dr. Thorne wrote in an email. He cautioned that, although this model of a wormhole was interesting and attractive, it was only one of countless possibilities. Dr. Thorne, who won the Nobel Prize in 2017 for his work on gravitational waves, explored the notion of wormholes as time machines in his book “Black Holes and Time Warps: Einstein’s Outrageous Legacy.”

    So I reached out by email to Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics, who has been tracking the star S2 for years from an advanced telescope in Chile. He broke my heart.

    He replied that he and his colleagues are close to measuring S2’s orbit with enough precision. That is not the problem, he added, “There is another ‘dragon’ that will make things very difficult.”

    There is enough stuff on our side of the wormhole contributing to S2’s jitter — dim stars, stellar black holes — that their turbulence would very likely swamp any signal from the other side. If there was a cosmic subway station to be found there, it might be buried under too much noise.

    Dr. Genzel, who called himself “a boy from the country side,” said he was “skeptical that we can tickle out the magic wormhole.”

    For now, the door is closed. Wormholes might exist, and we might never reliably detect them. The merely miraculous details of our own universe may block our view of the wonders of other worlds.

    See the full article here .


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  • richardmitnick 1:12 pm on April 13, 2019 Permalink | Reply
    Tags: "When a Black Hole Finally Reveals Itself, Dennis Overbye, It Helps to Have Our Very Own Cosmic Reporter", ,   

    From The New York Times: “When a Black Hole Finally Reveals Itself, It Helps to Have Our Very Own Cosmic Reporter” 

    New York Times

    From The New York Times

    April 12, 2019
    Aidan Gardiner

    Astronomers announced Wednesday that they had captured the first image of a black hole. The Times’s Dennis Overbye answers readers’ questions.

    The first image of a black hole, from the galaxy Messier 87.Credit Event Horizon Telescope Collaboration, via National Science Foundation

    Dennis Overbye, cosmic reporter for The New York Times, answering readers’ questions at his desk.Credit Aidan Gardiner/The New York Times

    When radio waves from the depths of a nearby galaxy known as Messier 87 traveled some 55 million light-years to a constellation of telescopes on Earth, revealing to humanity the face of a black hole for the first time, people around the planet paused in wonder.

    Why does it look like a doughnut? How scary is it when two of these things smash into each other? And if light can’t escape a black hole, what are we even looking at?

    Our coverage Wednesday of the first ever image of a black hole, by our cosmic reporter Dennis Overbye, drew a huge response from our readers. Dennis graduated from M.I.T. with a physics degree and was a Pulitzer Prize finalist in 2014 for his coverage for The New York Times of the race to find the Higgs boson. He sat down Thursday with his feet on his desk, beside a photo of the black hole, to answer some of our readers’ questions and respond to their feedback.

    Below are some of the exchanges that he had during an AMA on Reddit and in the comments on his article. They are edited for clarity.

    What does this image really tell us besides black holes are round?

    This is the first look into the central engine that generates the enormous energies put out by quasars, radio galaxies and other so-called active galactic nuclei. The action all starts down at the edge of oblivion, in a maelstrom of hot gas, gravity, magnetic fields and otherworldly pressures. It extends out beyond the far reaches of the galaxy, as jets of radio-wave energy moving at nearly the speed of light; these lobes of radio energy can accompany shock waves capable of blowing the gas out of galaxies or even entire clusters of them, preventing stars from forming. Through these mechanisms, black holes, blowing hot and cold, control the growth and structure of galaxies. It all starts in the accretion disk, the doughnut of doom.

    Why does it look like a “doughnut of doom” and not a sphere?

    When matter falls together into a black hole, or in almost any other situation, it has angular momentum, and takes on the shape of a flattened pancake spinning around the central attraction. Also, the black hole is probably spinning, pulling the disk around in the same direction. We are seeing the disk almost directly face-on, so it looks like a doughnut hole. (From edge-on it would look different.) Bent by gravity, light wraps around the hole on its way to our eyes, so the black hole magnifies and distorts the image of the accretion disk.

    Will we ever get a clearer image of this black hole?

    We will. The key is to observe black holes at shorter and shorter radio wavelengths, which allows more and more detail to be resolved. The latest images were recorded at a wavelength of 1.3 millimeters in the microwave band. The Event Horizon team hopes to go to shorter wavelengths in the future, and to use more antennas, including one in space, which would increase the size of their “virtual telescope” and also increase resolution.

    Do you feel that coverage of the breakthrough minimized the role of Katherine Bouman, a researcher at the Harvard-Smithsonian Center for Astrophysics?

    The issue of the unsung hero or heroine is a big problem, especially in Big Science, which the Event Horizon Telescope is surely part of.

    There were 207 people in the collaboration, according to one of the physicists I talked to that day. I am sure that many crucial contributions and rich anecdotes of behind-the-scenes science got missed.

    In time, these will come out in more thoughtful, longer narratives. On the day of the announcement there was a tsunami of information released at 9 a.m., and a rush to post stories as soon as possible, an unfortunate fact of the internet age.

    What does current science tell us is supposed to happen in the gravitational extremes of a black hole?

    That’s the biggie everybody wants to know. Whatever happens there, it probably is similar to what happened, maybe in reverse, in the Big Bang. Space, time, matter all go away, replaced by what? Some people think the answers might come from string theory, which unites gravity with quantum theory. But for now it remains an untestable, but mathematically elegant, speculation.

    What happens when two black holes collide?

    Such collisions have happened and been recorded by the LIGO gravitational wave observatory.

    They vibrated the space-time continuum like a drum and released as much energy in a fraction of a second as all the stars in the observable universe. The result in each case was an even bigger, blended black hole.

    But outside the event horizon, the gravitational field of a black hole is just like that of a star and it is no more dangerous. Black holes don’t go roaming around looking to swallow you. They only hurt if you touch them, in which case you won’t ever be able to let go. Otherwise they are like any other animal that you would just let go, and mind your own business.

    How is any of this relevant to our day-to-day lives?

    It can certainly provide context to your daily life, but it won’t move the markets. It will, or could, move your soul. However, Einstein, when he invented the sort of trampoline universe described by general relativity, did not dream that it would lead to pocket devices that keep time and tell you precisely where you are on Earth — that is to say, GPS. But they depend crucially on general relativity to tell you where you are. So who knows?

    See the full article here .


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  • richardmitnick 3:46 pm on October 30, 2018 Permalink | Reply
    Tags: , , Dame Susan Jocelyn Bell Burnell and pulsars, Dennis Overbye, , , , , Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics, S0-2, , ,   

    From The New York Times: “Trolling the Monster in the Heart of the Milky Way” 

    New York Times

    From The New York Times

    Oct. 30, 2018
    Dennis Overbye

    In a dark, dusty patch of sky in the constellation Sagittarius, a small star, known as S2 or, sometimes, S0-2, cruises on the edge of eternity. Every 16 years, it passes within a cosmic whisker of a mysterious dark object that weighs some 4 million suns, and that occupies the exact center of the Milky Way galaxy.

    Star S0-2 Keck/UCLA Galactic Center Group

    For the last two decades, two rival teams of astronomers, looking to test some of Albert Einstein’s weirdest predictions about the universe, have aimed their telescopes at the star, which lies 26,000 light-years away. In the process, they hope to confirm the existence of what astronomers strongly suspect lies just beyond: a monstrous black hole, an eater of stars and shaper of galaxies.

    For several months this year, the star streaked through its closest approach to the galactic center, producing new insights into the behavior of gravity in extreme environments, and offering clues to the nature of the invisible beast in the Milky Way’s basement.

    One of those teams, an international collaboration based in Germany and Chile, and led by Reinhard Genzel, of the Max Planck Institute for Extraterrestrial Physics, say they have found the strongest evidence yet that the dark entity is a supermassive black hole, the bottomless grave of 4.14 million suns.

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo

    ESO VLT 4 lasers on Yepun

    The evidence comes in the form of knots of gas that appear to orbit the galactic center. Dr. Genzel’s team found that the gas clouds circle every 45 minutes or so, completing a circuit of 150 million miles at roughly 30 percent of the speed of light. They are so close to the alleged black hole that if they were any closer they would fall in, according to classical Einsteinian physics.

    Astrophysicists can’t imagine anything but a black hole that could be so massive, yet fit within such a tiny orbit.

    The results provide “strong support” that the dark thing in Sagittarius “is indeed a massive black hole,” Dr. Genzel’s group writes in a paper that will be published on Wednesday under the name of Gravity Collaboration, in the European journal Astronomy & Astrophysics.

    “This is the closest yet we have come to see the immediate zone around a supermassive black hole with direct, spatially resolved techniques,” Dr. Genzel said in an email.

    Reinhard Genzel runs the Max Planck Institute for Extraterrestrial Physics in Munich. He has been watching S2, in the constellation Sagittarius, hoping it will help confirm the existence of a supermassive black hole.Credit Ksenia Kuleshova for The New York Times.

    The work goes a long way toward demonstrating what astronomers have long believed, but are still at pains to prove rigorously: that a supermassive black hole lurks in the heart not only of the Milky Way, but of many observable galaxies. The hub of the stellar carousel is a place where space and time end, and into which stars can disappear forever.

    The new data also help to explain how such black holes can wreak havoc of a kind that is visible from across the universe. Astronomers have long observed spectacular quasars and violent jets of energy, thousands of light-years long, erupting from the centers of galaxies.

    Roger Blandford, the director of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, said that there is now overwhelming evidence that supermassive black holes are powering such phenomena.

    “There is now a large burden of proof on claims to the contrary,” he wrote in an email. “The big questions involve figuring out how they work, including disk and jets. It’s a bit like knowing that the sun is a hot, gaseous sphere and trying to understand how the nuclear reactions work.”

    Images of different galaxies — some of which have evocative names like the Black Eye Galaxy, bottom left, or the Sombrero Galaxy, second left — adorn a wall at the Max Planck Institute.Credit Ksenia Kuleshova for The New York Times.

    Sheperd Doeleman, a radio astronomer at the Harvard-Smithsonian Center for Astrophysics, called the work “a tour de force.” Dr. Doeleman studies the galactic center and hopes to produce an actual image of the black hole, using a planet-size instrument called the Event Horizon Telescope.

    Event Horizon Telescope Array

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

    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 NOEMA interferometer
    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 Hawaii SAO
    Submillimeter Array Hawaii SAO

    ESO/NRAO/NAOJ ALMA Array, Chile

    South Pole Telescope SPTPOL
    South Pole Telescope SPTPOL

    NSF CfA Greenland telescope

    Greenland Telescope

    Future Array/Telescopes

    Plateau de Bure interferometer
    Plateau de Bure interferometer

    The study is also a major triumph for the European Southern Observatory, a multinational consortium with headquarters in Munich and observatories in Chile, which had made the study of S2 and the galactic black hole a major priority. The organization’s facilities include the Very Large Telescope [shown above], an array of four giant telescopes in Chile’s Atacama Desert (a futuristic setting featured in the James Bond film “Quantum of Solace”), and the world’s largest telescope, the Extremely Large Telescope, now under construction on a mountain nearby.

    ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

    Einstein’s bad dream

    Black holes — objects so dense that not even light can escape them — are a surprise consequence of Einstein’s general theory of relativity, which ascribes the phenomenon we call gravity to a warping of the geometry of space and time. When too much matter or energy are concentrated in one place, according to the theory, space-time can jiggle, time can slow and matter can shrink and vanish into those cosmic sinkholes.

    Einstein didn’t like the idea of black holes, but the consensus today is that the universe is speckled with them. Many are the remains of dead stars; others are gigantic, with the masses of millions to billions of suns. Such massive objects seem to anchor the centers of virtually every galaxy, including our own. Presumably they are black holes, but astronomers are eager to know whether these entities fit the prescription given by Einstein’s theory.

    Andrea Ghez, astrophysicist and professor at the University of California, Los Angeles, who leads a team of scientists observing S2 for evidence of a supermassive black hole UCLA Galactic Center Group

    Although general relativity has been the law of the cosmos ever since Einstein devised it, most theorists think it eventually will have to be modified to explain various mysteries, such as what happens at the center of a black hole or at the beginning of time; why galaxies clump together, thanks to unidentified stuff called dark matter; and how, simultaneously, a force called dark energy is pushing these clumps of galaxies apart.

    Women in STEM – Vera Rubin

    Fritz Zwicky discovered Dark Matter when observing the movement of the Coma Cluster

    Coma cluster via NASA/ESA Hubble

    But most of the real work was done by Vera Rubin

    Fritz Zwicky from http:// palomarskies.blogspot.com

    Astronomer Vera Rubin at the Lowell Observatory in 1965, worked on Dark Matter (The Carnegie Institution for Science)

    Vera Rubin measuring spectra, worked on Dark Matter (Emilio Segre Visual Archives AIP SPL)

    Vera Rubin, with Department of Terrestrial Magnetism (DTM) image tube spectrograph attached to the Kitt Peak 84-inch telescope, 1970. https://home.dtm.ciw.edu

    Dark Energy Survey

    Dark Energy Camera [DECam], built at FNAL

    NOAO/CTIO Victor M Blanco 4m Telescope which houses the DECam at Cerro Tololo, Chile, housing DECam at an altitude of 7200 feet

    The existence of smaller black holes was affirmed two years ago, when the Laser Interferometer Gravitational-Wave Observatory, or LIGO, detected ripples in space-time caused by the collision of a pair of black holes located a billion light-years away.

    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

    ESA/eLISA the future of gravitational wave research

    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)

    But those black holes were only 20 and 30 times the mass of the sun; how supermassive black holes behave is the subject of much curiosity among astronomers.

    “We already know Einstein’s theory of gravity is fraying around the edges,” said Andrea Ghez, a professor at the University of California, Los Angeles. “What better places to look for discrepancies in it than a supermassive black hole?” Dr. Ghez is the leader of a separate team that, like Dr. Genzel’s, is probing the galactic center. “What I like about the galactic center is that you get to see extreme astrophysics,” she said.

    Despite their name, supermassive black holes are among the most luminous objects in the universe. As matter crashes down into them, stupendous amounts of energy should be released, enough to produce quasars, the faint radio beacons from distant space that have dazzled and baffled astronomers since the early 1960s.

    Women in STEM – Dame Susan Jocelyn Bell Burnell

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Dame Susan Jocelyn Bell Burnell 2009

    Dame Susan Jocelyn Bell Burnell (1943 – ), still working from http://www. famousirishscientists.weebly.com

    Astronomers have long suspected that something similar could be happening at the center of the Milky Way, which is marked by a dim source of radio noise called Sagittarius A* (pronounced Sagittarius A-star).

    Sgr A* from ESO VLT

    SgrA* NASA/Chandra

    SGR A* , the supermassive black hole at the center of the Milky Way. NASA’s Chandra X-Ray Observatory

    But the galactic center is veiled by dust, making it all but invisible to traditional astronomical ways of seeing.

    Seeing in the dark

    Reinhard Genzel grew up in Freiburg, Germany, a small city in the Black Forest. As a young man, he was one of the best javelin throwers in Germany, even training with the national team for the 1972 Munich Olympics. Now he is throwing deeper.

    He became interested in the dark doings of the galactic center back in the 1980s, as a postdoctoral fellow at the University of California, Berkeley, under physicist Charles Townes, a Nobel laureate and an inventor of lasers. “I think of myself as a younger son of his,” Dr. Genzel said in a recent phone conversation.

    In a series of pioneering observations in the early 1980s, using detectors that can see infrared radiation, or heat, through galactic dust, Dr. Townes, Dr. Genzel and their colleagues found that gas clouds were zipping around the center of the Milky Way so fast that the gravitational pull of about 4 million suns would be needed to keep it in orbit. But whatever was there, it emitted no starlight. Even the best telescopes, from 26,000 light years away, could make out no more than a blur.

    An image of the central Milky Way, which contains Sagittarius A*, taken by the VISTA telescope at the E.S.O.’s Paranal Observatory, mounted on a peak just next to the Very Large Telescope.CreditEuropean Southern Observatory/VVV Survey/D. Minniti/Ignacio Toledo, Martin Kornmesser

    Part of ESO’s Paranal Observatory, the VLT Survey Telescope (VISTA) observes the brilliantly clear skies above the Atacama Desert of Chile. It is the largest survey telescope in the world in visible light.
    Credit: ESO/Y. Beletsky, with an elevation of 2,635 metres (8,645 ft) above sea level

    Two advances since then have helped shed some figurative light on whatever is going on in our galaxy’s core. One was the growing availability in the 1990s of infrared detectors, originally developed for military use. Another was the development of optical techniques that could drastically increase the ability of telescopes to see small details by compensating for atmospheric turbulence. (It’s this turbulence that blurs stars and makes them twinkle.)

    Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT.

    These keen eyes revealed hundreds of stars in the galaxy’s blurry core, all buzzing around in a circle about a tenth of a light year across. One of the stars, which Dr. Genzel calls S2 and Dr. Ghez calls S-02, is a young blue star that follows a very elongated orbit and passes within just 11 billion miles of the mouth of the putative black hole every 16 years.

    During these fraught passages, the star, yanked around an egg-shaped orbit at speeds of up to 5,000 miles per second, should experience the full strangeness of the universe according to Einstein. Intense gravity on the star’s surface should slow the vibration of light waves, stretching them and making the star appear redder than normal from Earth.

    This gravitational redshift, as it is known, was one of the first predictions of Einstein’s theory. The discovery of S2 offered astronomers a chance to observe the phenomenon in the wild — within the grip of gravity gone mad, near a supermassive black hole.

    Left, calculations left out at the Max Planck Institute, viewed from above, right.Credit Ksenia Kuleshova for The New York Times

    In the wheelhouse of the galaxy

    To conduct that experiment, astronomers needed to know the star’s orbit to a high precision, which in turn required two decades of observations with the most powerful telescopes on Earth. “You need twenty years of data just to get a seat at this table,” said Dr. Ghez, who joined the fray in 1995.

    And so, the race into the dark was joined on two different continents. Dr. Ghez worked with the 10-meter Keck telescopes, located on Mauna Kea, on Hawaii’s Big Island.

    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level, showing also NASA’s IRTF and NAOJ Subaru

    UCO Keck Laser Guide Star Adaptive Optics

    Dr. Genzel’s group benefited from the completion of the European Southern Observatory’s brand new Very Large Telescope [above] array in Chile.

    The European team was aided further by a new device, an interferometer named Gravity, that combined the light from the array’s four telescopes.

    ESO GRAVITY insrument on The VLTI, interferometric instrument operating in the K band, between 2.0 and 2.4 μm. It combines 4 telescope beams and is designed to peform both interferometric imaging and astrometry by phase referencing. Credit: MPE/GRAVITY team

    Designed by a large consortium led by Frank Eisenhauer of the Max Planck Institute, the instrument enabled the telescope array to achieve the resolution of a single mirror 130 meters in diameter. (The name originally was an acronym for a long phrase that included words such as “general,” “relativity,” and “interferometry,” Dr. Eisenhauer explained in an email.)

    “All of the sudden, we can see 1,000 times fainter than before,” said Dr. Genzel in 2016, when the instrument went into operation. In addition, they could track the movements of the star S2 from day to day.

    Meanwhile, Dr. Ghez was analyzing the changing spectra of light from the star, to determine changes in the star’s velocity. The two teams leapfrogged each other, enlisting bigger and more sophisticated telescopes, and nailing down the characteristics of S2. In 2012 Dr. Genzel and Dr. Ghez shared the Crafoord Prize in astronomy, an award nearly as prestigious as the Nobel. Events came to head this spring and summer, during a six-month period when S2 made its closest approach to the black hole.

    “It was exciting in the middle of April when a signal emerged and we started getting information,” Dr. Ghez said.

    On July 26, Dr. Genzel and Dr. Eisenhauer held a news conference in Munich to announce that they had measured the long-sought gravitational redshift. As Dr. Eisenhauer marked off their measurements, which matched a curve of expected results, the room burst into applause.

    “The road is wide open to black hole physics,” Dr. Eisenhauer proclaimed.

    In an email a month later, Dr. Genzel explained that detecting the gravitational redshift was only the first step: “I am usually a fairly sober, and sometimes pessimistic person. But you may sense my excitement as I write these sentences, because of these wonderful results. As a scientist (and I am 66 years old) one rarely if ever has phases this productive. Carpe Diem!”

    In early October, Dr. Ghez, who had waited to observe one more phase of the star’s trip, said her team soon would publish their own results.

    A monster in the basement

    In the meantime, Dr. Genzel was continuing to harvest what he called “this gift from nature.”

    The big break came when his team detected evidence of hot spots, or “flares,” in the tiny blur of heat marking the location of the suspected black hole. A black hole with the mass of 4 million suns should have a mouth, or event horizon, about 16 million miles across — too small for even the Gravity instrument to resolve from Earth.

    The hot spots were also too small to make out. But they rendered the central blur lopsided, with more heat on one side of the blur than the other. As a result, Dr. Genzel’s team saw the center of that blur of energy shift, or wobble, relative to the position of S2, as the hot spot went around it.

    As a result, said Dr. Genzel, “We see a little loop on the sky.” Later he added, “This is the first time we can study these important magnetic structures in a spatially resolved manner just like in a physics laboratory.”

    He speculated that the hot spots might be produced by shock waves in magnetic fields, much as solar flares erupt from the sun. But this might be an overly simplistic model, the authors cautioned in their paper. The effects of relativity turn the neighborhood around the black hole into a hall of mirrors, Dr. Genzel said: “Our statements currently are still fuzzy. We will have to learn better to reconstruct reality once we better understand exactly these mirages.”

    The star has finished its show for this year. Dr. Genzel hopes to gather more data from the star next year, as it orbits more distantly from the black hole. Additional observations in the coming years may clarify the star’s orbit, and perhaps answer other questions, such as whether the black hole was spinning, dragging space-time with it like dough in a mixer.

    But it may be hard for Dr. Genzel to beat what he has already accomplished, he said by email. For now, shrink-wrapping 4 million suns worth of mass into a volume just 45 minutes around was a pretty good feat “for a small boy from the countryside.”

    See the full article here .


    Please help promote STEM in your local schools.

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  • richardmitnick 1:37 pm on December 29, 2017 Permalink | Reply
    Tags: , , , , Breakthrough Star Shot, , Dennis Overbye, For astronomers the biggest problem with E.T. is not the occasional claim of a mysterious light in the sky but the fact that we are not constantly overwhelmed with them, How dare we think that the physics we have today is all that there is, , Scientists are also trained to look at nature with ruthless rigor and skepticism, Scientists are not the killjoys in all this., , U.F.O.'s   

    From NYT: “U.F.O.s: Is This All There Is?” 

    New York Times

    The New York Times

    DEC. 29, 2017
    Dennis Overbye

    A U.F.O. in New Mexico in 1957. For astronomers, the biggest problem with alien visitation is not the occasional claim of mysterious light in the sky, but the fact that we’re not constantly overwhelmed with them. Credit Bettmann, via Getty Images

    Hey, Mr. Spaceman,

    Won’t you please take me along?

    I won’t do anything wrong.

    Hey, Mr. Spaceman,

    Won’t you please take me along for a ride?

    So sang the Byrds in 1966, after strange radio bursts from distant galaxies called quasars had excited people about the possibility of extraterrestrial intelligence.

    I recalled those words recently when reading the account of a pair of Navy pilots who were outmaneuvered and outrun by a U.F.O. off the coast of San Diego back in 2004. Cmdr. David Fravor said later that he had no idea what he had seen.

    “But,” he added, “I want to fly one.”

    His story was part of a bundle of material released recently about a supersecret $22 million Pentagon project called the Advanced Aerospace Threat Identification Program, aimed at investigating U.F.O.s. The project was officially killed in 2012, but now it’s being resurrected as a nonprofit organization.

    Disgruntled that the government wasn’t taking the possibility of alien visitors seriously, a group of former defense officials, aerospace engineers and other space fans have set up their own group, To the Stars Academy of Arts & Science. One of its founders is Tom DeLonge, a former punk musician, record producer and entrepreneur, who is also the head of the group’s entertainment division.

    For a minimum of $200, you can join and help finance their research into how U.F.O.s do whatever it is they do, as well as telepathy and “a point-to-point transportation craft that will erase the current travel limits of distance and time” by using a drive that “alters the space-time metric” — that is, a warp drive going faster than the speed of light, Einstein’s old cosmic speed limit.

    “We believe there are transformative discoveries within our reach that will revolutionize the human experience, but they can only be accomplished through the unrestricted support of breakthrough research, discovery and innovation,” says the group’s website.

    A U.F.O. spotted by Navy pilots near San Diego in 2004. Credit Department of Defense

    I’m not holding my breath waiting for progress on telepathy or warp drive, but I agree with at least one thing that one official with the group said. That was Steve Justice, a former engineer at Lockheed Martin’s famous Skunk Works, where advanced aircraft like the SR-71 high-altitude super-fast spy plane were designed.

    “How dare we think that the physics we have today is all that there is,” he said in an interview published recently in HuffPost.

    I could hardly agree more, having spent my professional life in the company of physicists and astronomers trying to poke out of the cocoon of present knowledge into the unknown, to overturn Einstein and what passes for contemporary science. Lately, they haven’t gotten anywhere.

    The last time physicists had to deal with faster-than-light travel was six years ago, when a group of Italy-based physicists announced that they had seen the subatomic particles known as neutrinos going faster than light. It turned out they had wired up their equipment wrong.

    So far Einstein is still the champ. But surely there is so much more to learn. A lot of surprises lie ahead, but many of the most popular ideas on how to transcend Einstein and his peers are on the verge of being ruled out. Transforming science is harder than it looks.

    While there is a lot we don’t know, there is also a lot we do know. We know how to turn on our computers and let gadgets in our pocket navigate the world. We know that when physical objects zig and zag through a medium like air, as U.F.O.s are said to do, they produce turbulence and shock waves. NASA engineers predicted to the minute when the Cassini spacecraft would dwindle to a wisp of smoke in Saturn’s atmosphere last fall.

    In moments like this, I take comfort in what the great Russian physicist and cosmologist Yakov Zeldovich, one of the fathers of the Soviet hydrogen bomb, once told me. “What science has already taken, it will not give back,” he said.

    Scientists are not the killjoys in all this.

    In the astronomical world, the border between science fact and science fiction can be very permeable, perhaps because many scientists grew up reading science fiction. And astronomers forever have their noses pressed up against the window of the unknown. They want to believe more than anybody, and I count myself among them.

    Since the asteroid named Oumuamua was first noticed flying through our solar system in October, researchers have been monitoring for alien signals, so far to no avail. Credit M. Kornmesser/Agence France-Presse — Getty Images

    But they are also trained to look at nature with ruthless rigor and skepticism. For astronomers, the biggest problem with E.T. is not the occasional claim of a mysterious light in the sky, but the fact that we are not constantly overwhelmed with them.

    Half a century ago, the legendary physicist Enrico Fermi concluded from a simple back-of-the-envelope calculation that even without warp drive, a single civilization could visit and colonize all the planets in the galaxy in a fraction of the 10-billion-year age of the Milky Way.

    “Where are they?” he asked.

    Proponents of SETI, the search for extraterrestrial intelligence, have been debating ever since. One answer I like is the “zoo hypothesis,” according to which we have been placed off-limits, a cosmic wildlife refuge.

    Another answer came from Jill Tarter, formerly the director of research at the SETI Institute in Mountain View, Calif. “We haven’t looked hard enough,” she said when I asked her recently.

    If there was an iPhone sitting under a rock on the Moon or Mars, for example, we would not have found it yet. Our own latest ideas for interstellar exploration involve launching probes the size of postage stamps to Alpha Centauri.

    In the next generation, they might be the size of mosquitoes. By contrast, the dreams of some U.F.O. enthusiasts are stuck in 1950s technology.

    Still, we keep trying.

    Last fall when a strange object — an interstellar asteroid now named Oumuamua — was found cruising through the solar system, astronomers’ thoughts raced to the Arthur C. Clarke novel Rendezvous With Rama, in which the object was an alien spaceship. Two groups have been monitoring Oumuamua for alien radio signals, so far to no avail.

    Meanwhile, some astronomers have speculated that the erratic dimming of a star known as “Boyajian’s star” or “Tabby’s star,” after the astronomer Tabetha Boyajian, could be caused by some gigantic construction project orbiting the star. So far that has not worked out, but none of the other explanations — dust or a fleet of comets — have, either.

    A pair of Harvard astronomers suggested last spring that mysterious sporadic flashes of energy known as fast radio bursts coming from far far away are alien transmitters powering interstellar spacecraft carrying light sails. “Science isn’t a matter of belief, it’s a matter of evidence,” the astronomer Avi Loeb said in a news release from Harvard. “Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge.”

    U.F.O. investigations are nothing new. The most famous was the Air Force’s Project Blue Book, which ran from 1952 to 1970 and examined more than 12,000 sightings.

    Most U.F.O. sightings turn out to be swamp gas and other atmospheric anomalies, Venus, weird reflections or just plain hoaxes. But there is a stubborn residue, a few percent that resist easy explication, including now Commander Fravor’s story. But that’s a far cry from proving they are alien or interstellar.

    I don’t know what to think about these stories, often told by sober, respected and professional observers — police officers, pilots, military officials — in indelible detail. I always wish I could have been there to see it for myself.

    Then I wonder how much good it would do to see it anyway.

    Recently I ran into my friend Mark Mitton, a professional magician, in a restaurant. He came over to the table and started doing tricks. At one point he fanned the card deck, asked my daughter to pick one, and then asked her to shuffle the deck, which she did expertly.

    Mr. Mitton grabbed the deck and sprayed the cards in the air. There was my daughter’s card stuck to a mirror about five feet away. How did it get there? Not by any new physics. Seeing didn’t really help.

    As modern psychology and neuroscience have established, the senses are an unreliable portal to reality, whatever that is.

    Something might be happening, but we don’t know what it is. E.T., if you’re reading this, I’m still waiting to take my ride.

    See the full article here .

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  • richardmitnick 11:46 am on October 18, 2017 Permalink | Reply
    Tags: , , Dennis Overbye,   

    From NYT: “How Dennis Overbye Makes Space-Time Relatable” 

    New York Times

    The New York Times

    OCT. 17, 2017

    Dennis Overbye, a Times science reporter, inside the Large Hadron Collider in Switzerland. No image credit.

    Dennis Overbye, The New York Times’s cosmic affairs correspondent, has never owned a telescope. They were of little use in the cloudy environs of Mercer Island, Wash., where he grew up.

    Instead, his interest in science began, as it did for many who came of age immersed in the starward ambitions of the space age, with science fiction. There were the paperbacks by Arthur C. Clarke, Isaac Asimov and Robert Heinlein — “that whole crew who had imagined the future of the human race as I saw it now being played out by Sputnik and Apollo,” Mr. Overbye said.

    In the nearly 20 years he has worked for The Times, Mr. Overbye has similarly tried to nourish the imaginations of others. “My job as I see it is to relate people to the universe they live in,” he said. “It’s kind of everybody’s business what the universe is and what it means to be here.”

    He has covered the discovery of planets beyond our sun; the detection of fundamental particles and the gravitational waves created by colliding black holes; and dark energy, the mysterious and inscrutable substance that makes up 70 percent of the universe and may very well determine its destiny. Earlier this week, Mr. Overbye wrote about the first collision of neutron stars ever observed. “I don’t look at page views,” he said. “Very little of what I write about moves the markets.”

    Still, Mr. Overbye’s stories often live where the earthly meets the cosmic. His first book, “Lonely Hearts of the Cosmos,” recounts the birth of cosmology through the personal dramas of its founders and was nominated for the National Book Critics Circle Award in 1991. And in 2014, he was named a Pulitzer Prize finalist for his reporting on the race to discover the Higgs boson, which focused on the lives of just a handful of the thousands of scientists swept up in the search for “the God particle.”

    Once Mr. Overbye identifies a story, he said, the work is in putting it in terms people can understand. “Metaphors are very important to the way I write,” he said. The results are vivid descriptions that surpass mere translation. Einstein’s epiphany that space-time is distorted by gravity, for instance, renders the universe as “the ultimate sagging mattress,” and elementary particles derive mass from the Higgs boson “the way politicians draw succor from cheers and handshakes at the rope line.”

    “I once compared the Milky Way galaxy to a piñata that the Kepler spacecraft had whacked and hundreds or thousands of new planets had fallen out,” Mr. Overbye said.

    Sometimes the effect can be rhapsodic. Astronomers on Monday announced the first detection of a kilonova, the collision of hyperdense dead stars thought to be responsible for creating many of the heavier elements in the universe, including gold, silver, platinum and uranium. As Mr. Overbye describes it: “All the atoms in your wedding band, in the pharaoh’s treasures and the bombs that destroyed Hiroshima and still threaten us all, so the story goes, have been formed in cosmic gong shows that reverberated across the heavens.”

    Yet although it may seem that scientists are observing novel celestial events all the time, the pace of paradigm-shifting discoveries in cosmology has begun to slow; these days experimental results rarely shake theory off its foundations. (In June, Mr. Overbye reported on the existential crisis facing scientists at the Large Hadron Collider, where the Higgs boson was detected five years ago, now that one of particle physics’s biggest mysteries has essentially been licked.)

    “Huge discoveries are not moving the field,” said Jim Glanz, an investigative reporter at The Times who started on the Science desk under Mr. Overbye. As a result, Mr. Glanz described this moment in science journalism as a doldrums, which might tempt many to overstate the incremental or obscure. But not Mr. Overbye. “Dennis doesn’t like to pull a rabbit out of a hat,” Mr. Glanz said. “He’s writing ‘War and Peace.’ The disappointments have to be as dramatized as breakthroughs.”

    It is a reality in which Mr. Overbye feels perfectly comfortable. In fact, he prefers to think of himself as “an evangelist of Cosmic Ignorance” — that we haven’t even learned the right questions to ask yet. As he put it in the preface to “Lonely Hearts”: “Science, inching along by trial-and-error and by doubt, is a graveyard of final answers.”

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  • richardmitnick 9:13 am on December 26, 2014 Permalink | Reply
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    From Dennis Overbye at NYT: “Do Aliens Know It’s Christmas?” 

    New York Times

    The New York Times

    DEC. 22, 2014
    NYT Dennis Overbye Older
    Dennis Overbye

    A star appeared in the East.

    Following it, so the biblical story goes, three Magi urged on by a nervous King Herod arrived in Bethlehem and discovered the news that many of us celebrate with bells, lights and too much sugar and alcohol every year at this time: The son of God had come to die for our sins.

    Peace on earth and good will to men is fine, as far as it goes. But some astronomers and forward-thinking theologians wonder how the rest of the universe is supposed to get the message.

    If your dog can go to heaven, can E. T.? Astronomers have discovered in the last two decades that there are probably tens of billions of potentially habitable planets in the Milky Way. Only last week, NASA scientists reported that Mars had blown a methane sigh into the face of the Curiosity rover, though whether from microbes or geochemical grumblings may not be known until there are geologists’ boots on the Red Planet.

    NASA Mars Curiosity Rover

    So it’s not so crazy to imagine other living creatures scattered through the billions of years and light-years of cosmic history.

    Did Christ come to die for their sins, too?

    Or as Geoffrey Marcy, an exoplanet explorer and holder of the Watson and Marilyn Alberts Chair in the Search for Extraterrestrial Intelligence at the University of California, Berkeley, said not long ago in an email, “But do they know it’s Christmas?”

    Surely, earthlings were not the only beings in the Milky Way blessed in God’s eyes, he elaborated, saying that he liked to tease public audiences with the question. “Conversations about religion with intelligent beings from an exoplanet might jolt humanity into realizing how parochial our beliefs are,” he said.

    Pope Francis suggested in a homily in May that he would baptize Martians if they landed in St. Peter’s Square and asked for it.

    How, you may ask, might E.T. have sinned? On Earth, violence and suffering are embedded in the Darwinian struggle for survival that produced us, says Ted Peters, a professor who runs a group on “astrotheology” at the Center for Theology and the Natural Sciences in Berkeley. If aliens are made of the same stuff we are, Dr. Peters wrote in the Philosophical Transactions of the Royal Society in 2011, “might they also share the ambiguity between good and evil that we are familiar with?”

    But what if they are computers or other forms of artificial intelligence that futurists say might ultimately supplant us as masters of the universe?

    Christian scholars like Dr. Peters and indeed the pope agree that the possibility of redemption probably extends to all of creation, even perhaps the inanimate world.

    “How could he be God and leave extraterrestrials in sin?” asks the Rev. George V. Coyne, the former director of the Vatican Observatory and now a Jesuit priest who holds the McDevitt Chair of Religious Philosophy at Le Moyne College in Syracuse, in the 2000 book Many Worlds: The New Universe, Extraterrestrial Life and the Theological Implications, edited by the astronomer Steven J. Dick, a former chief historian for NASA. “After all, he was good to us. Why should he not be good to them?”

    This has engendered a sort of how-many-angels-can-dance-on-the-head-of-a-pin argument about whether Christ died for the entire cosmos, or whether the son of God or the metaphysical equivalent has to be born and die on every populated planet.

    Each alternative sounds ridiculous on the face of it. The first alternative would make Earth the center of the universe again, not just in space but in time, carrying the hopes for the salvation of beings that lived and died millions or billions of years ago and far, far away.

    The second alternative would be multiple incarnations, requiring every civilization to have its own redeemer — “its own adventure with God,” in the words of Professor Peters. That is hardly better. As the old troublemaker Thomas Paine wrote in The Age of Reason, “In this case, the person who is irreverently called the son of God, and sometimes God himself, would have nothing else to do than to travel from world to world, in an endless succession of deaths, with scarcely a momentary interval of life.”

    Distinguished theologians have come down on different sides of this issue; after all, it’s not up to us to say what God could or could not do. “God doesn’t seem to be limited by history and communication,” Dr. Peters said in an interview, playing the devil’s advocate, so to speak, for the notion of a single incarnation for the entire cosmos. In that case, the consequences would not be limited to “people who get emails about it.”

    “Every sentient being is blessed by God’s grace whether they know about it or not,” he said.

    Seeking scientific as well as spiritual guidance, I dialed up Guy Consolmagno at the Vatican Observatory. He is a Jesuit priest and a co-author, with his fellow Jesuit Paul Mueller, of Would You Baptize an Extraterrestrial? … And Other Questions from the Astronomer’s In-box at the Vatican Observatory.

    Vatican Observatory
    Vatican Observatory Interior
    Vatican Observatory

    Brother Consolmagno spent 10 years working and teaching as a planetary scientist, specializing in meteorites, before joining the Jesuits. Last year, he was awarded the Carl Sagan Medal by the Division for Planetary Sciences of the American Astronomical Society, for communication in planetary science. He said that Christmas for aliens could be a wonderful story, but that he didn’t have any answers and that that was part of the fun.

    “One incarnation seems absurd but not inconsistent with the data,” he said by phone from Florida, where he was watching manatees.

    There is no data, I pointed out.

    “Exactly!” he responded, laughing.

    Contrary to popular perception, he said, religion, like science, is not a closed book. “Science,” he said, “is stuff we understand about truths we only partially grasp. Religion is trying to get closer to truths we don’t understand.”

    The more you know, the more you know you don’t understand, he said. “That’s called progress.”

    The challenge in any person’s or species’ life, he added, is how to learn others’ truths without giving up your own.

    Dr. Marcy, with tongue fairly firmly in cheek, evoked what he called “the multigod model of the universe.”

    There might be room in the universe for more than one truth, he said, if every inhabited planet had its own gods. The inhabitants might be as certain of their beliefs as we humans are of ours.

    “The deities have carved out their operating galactic territories, like so many cosmic Corleone families,” Dr. Marcy said.

    “Only with SETI research,” he went on, referring to the search for extraterrestrial intelligence, “will we learn whether our particular God is alone in the universe.”

    His point was echoed, if less ironically, by Nancy Ellen Abrams, a lawyer, philosopher and author of a forthcoming book, A God That Could Be Real: Spirituality, Science and the Future of Our Planet, which argues that God is an emergent phenomenon, a result of the complexity of the universe and human aspirations rather than the cause of them — although no less real for that. “Our god is the god of humanity; it has nothing to do with aliens,” she said in an interview.

    In the best of all possible universes, all these truths and gods would mysteriously and perhaps revelatorily overlap. But maybe that is wishful thinking and there is another, more chilling answer to Christmas.

    Take that star in the East; it was the subject of a classic story by Arthur C. Clarke, a science fiction author and space visionary.

    In The Star, published in 1955, an expedition to the site of an old supernova explosion discovers the remains of an ancient civilization, carefully preserved because its members knew they were about to be obliterated. The story is told through the eyes of the astrophysicist onboard, a Jesuit. He is able to figure out exactly when the explosion that doomed this race took place, and exactly what it would have looked like 2,000 years ago from Earth.

    “There can be no reasonable doubt,” he concludes, “the ancient mystery is solved at last. Yet, oh God, there were so many stars you could have used. What was the need to give these people to the fire, that the symbol of their passing might shine above Bethlehem?”

    Brother Consolmagno, who was a science fiction aficionado as an undergraduate at M.I.T., knows the story.

    “That’s not the kind of god I’m happy with,” he said.

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  • richardmitnick 3:44 pm on December 24, 2014 Permalink | Reply
    Tags: , , , , , Dennis Overbye,   

    FromDennis Overbye at The New York Times: Birth of a Star 

    New York Times

    The New York Times

    In galactic nurseries like the Orion Nebula, clouds of gas and dust mingle, birthing new stars and planetary systems. The ALMA radio telescope made a recent observation of possible planets being born.

    In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Hubble

    NASA Hubble ACS
    Hubble’s Advanced Camera for Surveys

    We might be stardust, Joni Mitchell sang of Woodstock in 1969, echoing what was already a half-century of hard-headed astronomical truth. But astronomers have struggled to understand just exactly how stardust goes from being cosmic smog, littering the lanes of the galaxy, to planets and people.

    Recently, however, astronomers using the Atacama Large Millimeter/submillimeter Array, or ALMA, an international radio telescope in the high desert of Chile, obtained what might be the best picture yet of dust in the act of turning into planets.

    ALMA Array
    ALMA Array

    It shows a young star named HL Tauri, about 450 light-years from here and thus in the constellation of Taurus. The star is surrounded by a glowing disk of dust and gas about 22 billion miles across — about four times the size of Neptune’s orbit, which bounds the realm of official planets in our own solar system ever since the outlier Pluto was bounced from the fraternity of planets.

    HL Tauri

    Produced by: Jason Drakeford, Jonathan Corum and Dennis Overbye

    Most significant, the disk is scored with dark rings or grooves, like a record or the rings of Saturn.

    That, the ALMA astronomers who took the picture say, is most likely the signature of a new planetary system in the making. As clumps of dust accumulate and grow into planets at various distances from the star, they gobble up the dust near them, scouring clear paths around the star and leaving a pattern of bright and dark rings, explained Catherine Vlahakis, an ALMA astronomer.

    The ALMA picture represents only the end of the beginning of a long cycle of birth and death for stars and planets.

    It begins in galactic nurseries like the Orion nebula, where Christmas-colored clouds of gas and dust mingle primordial elements left over from the Big Bang with the ashes of more recent stars that have died and exploded. Rumbled by explosions and raked by radiation and winds from new stars, the clouds collapse under their own weight.

    The result is a cosmic baby boom. Space in Orion is littered with small globs of gas and dust, harboring baby stars and their planets in the making. Stellar tadpoles, if you like, in a cloudy pond.

    It can take a million years or so for clouds as massive as the Sun to collapse to the dimensions of a solar system. As they shrink, their centers spin up into swirling maelstroms, protostars surrounded by protoplanetary dust.

    If the cloud is big enough, gravity will eventually compress it to the point that it is hot enough to ignite thermonuclear reactions — a star is born and begins to burn its way out of its birth bag.

    At the same time, radiation from powerful stars nearby is eating away the cocoon from the outside, setting up a deadly race. Too much radiation from the outside will burn off not only the cocoon but the disk around the new star as well, leaving it naked and alone, without the potential for planets. Luckily that didn’t happen here.

    If the disk survives, irregularities in it can grow — first by electrical forces as particles randomly collide and stick, then by gravity as clumps attract one another and sweep their orbits clean like the dark grooves of HL Tauri.

    Astronomers estimate that HL Tauri is only a million years old, a blink in the long lifetime of a star. In an email Dr. Vlahakis said that stars this young had not been expected to have planets big enough to gouge grooves in their planetary disks so soon. “This suggests that planet formation might happen faster than previously thought,” she said.

    Astronomers have recently estimated that there are at least as many planets in the Milky Way as there are stars. What is happening here has happened billions of times already in the galaxy. The putative planets of HL Tauri have millions or billions of years to make something more of themselves. Life got lucky once in the Milky Way — what are the odds it could happen again?

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  • richardmitnick 7:01 am on December 2, 2014 Permalink | Reply
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    From NYT: “New Images Refine View of Infant Universe” 

    New York Times

    The New York Times

    DEC. 1, 2014

    NYT Dennis Overbye
    Dennis Overbye

    In a throwback to another era in cosmic history, astronomers on Monday discussed the birth of the universe in a 15th-century palace, the Palazzo Costabili in Ferrara, Italy, where the amenities do not include Internet access.

    The subject of Planck 2014, as the meeting is called, is a new baby picture — and all of the accompanying vital statistics — of the universe when it was 380,000 years old and space was as hot as the surface of the sun. The portrait taker was the European Space Agency’s Planck satellite, which spent three years surveying a haze of microwave radiation left over from the last moments of the Big Bang with a bevy of sensitive radio receivers.

    Cosmic Background Radiation Planck

    ESA Planck

    The data will not be published until Dec. 22 in the journal Astronomy & Astrophysics, and the lack of Internet access frustrated astronomers who had planned on watching a webcast of the proceedings but found themselves relying on Twitter feeds instead.

    At least, they reported, the coffee was suitably strong.

    The new data largely confirms and refines the picture from a temperature map of the microwaves that Planck scientists, a multinational collaboration led by Jan Tauber of the European Space Agency, produced in 2013, showing the faint irregularities from which gargantuan features like galaxies would grow. Its microwave portrait reveals a universe 13.8 billion years old that is precisely mysterious, composed of 4.9 percent atomic matter, 26.6 percent mysterious dark matter that is not atomic, and 68.5 percent of even more mysterious dark energy, the glib name for whatever it is that seems to be blowing the universe apart.

    A map of a patch of sky showing the temperature and polarization of cosmic microwaves from the end of the Big Bang, as reflected by dust swirling in the magnetic field of the Milky Way. Credit European Space Agency

    The result is a resounding victory for a sort of Standard Model of Cosmology that has grown up over the last two decades, said Lyman Page, a Princeton astrophysicist, in a phone call from Ferrara. “What we see is pretty impressive,” he said. “It’s amazing that just six parameters describe the universe.”

    Standard Model of Cosmology Inflation Lambda Model
    Lambda-CDM model

    Standard Model of Cosmology
    Another view

    Cosmologists still do not know what dark matter — the material that provides the gravitational scaffolding for galaxies — is, but the Planck results have increased their knowledge of what it is not, according to the French Center for National Scientific Research.

    Recently space experiments like NASA’s Fermi Gamma-ray Space Telescope and Alpha Magnetic Spectrometer have recorded excess cosmic ray emissions that, some say, could be evidence of a certain kind of dark matter particles colliding and annihilating one another.

    NASA Fermi Telescope

    NASA AMS02 device

    After Planck, we need another answer for those experiments, the French agency concluded in a statement.

    Neal Weiner, a particle theorist at New York University, who is not part of Planck, concurred. That model of dark matter, he said in an email, if not completely excluded, now could be severely constrained. “If this holds up, at the very least a possibility to discover dark matter is now diminished.”

    Planck dealt a blow to another possible dark matter candidate, namely a brand of the ghostly particles known as neutrinos. Physicists have known of three types of neutrinos for some time and have wondered if there were any more, whose accumulated mass would affect the evolution of the universe. Planck’s results leave little room for a fourth kind, so-called sterile neutrinos.

    Compounding the frustration of cosmologists in the room in Ferrara and at large was an issue that has galvanized them for the better part of a year: whether astronomers had detected the very beginnings of the Big Bang in the form of space-time ripples known as gravitational waves.

    Gravitational Wave Background
    Gravitational Waves per BICEP2 radio telescope.

    BICEP 2
    BICEP 2 interior
    BICEP 2 with South Pole Telescope

    The added value of the new Planck data is a map showing how the microwaves are polarized, information that could shed light on what was going on when the universe was a trillionth of a trillionth of a trillionth of a second old, and in the grip of forces about which physicists can only speculate.

    Among the hottest topics of speculation these days is the idea — known as inflation — that the universe underwent a violent and brief surge of expansion in the earliest moments, settling the geometry and other aspects of the present universe. Such an explosion, theorists say, would have left faint corkscrew swirls, known technically as B-modes, in the pattern of polarization of the microwaves.

    In March there was much excitement when a team of American astronomers operating a radio telescope at the South Pole called Bicep2 announced they had detected such a pattern. Alan Guth of M.I.T., one of the inventors(?) [theorist would be better] of inflation, was at the news conference at Harvard announcing the results.

    Alan Guth
    Alan Guth

    After three months of spirited debate, the astronomers conceded, however, that their signal could have been caused by interstellar dust, which can also twist the microwaves.

    Enter Planck, which observed the microwaves in nine different frequencies, making it easy to distinguish dust. Bicep2 had only one frequency.

    A preliminary report from Planck in September confirmed that there was enough dust in Bicep2’s patch of sky to account for the twisting, but there are still large uncertainties that leave room for primordial gravitational waves.

    Subsequently, Planck and Bicep agreed to pool their data for a joint analysis.

    Planck scientists have meanwhile published their own polarization maps, which astronomers say will be useful for studying how the anti-gravitational push of dark energy and the gravitational pull of dark matter orchestrated the growth of galaxies and the universe when it was two or three billion years old — a sensitive age.

    The bumps in the microwave maps that eventually grow to galaxies amount to a temperature difference of only about 75-millionths of a Kelvin, in an otherwise uniform hiss. To measure polarization, radio astronomers have to discern temperature differences about a tenth of that.

    The difficulty of doing this research, while the world looks on, can be gauged by the number of missed deadlines. Planck researchers originally hoped to have their polarization studies done this summer. Recently they had set November as their deadline, aiming to present the results at this conference in Ferrara. Likewise, the joint Bicep/Planck paper is now expected this month or in January.

    Asked about this, David Spergel, a Princeton cosmologist and veteran of cosmic microwave studies who had spent the day fielding Twitter messages from Ferrara, said he had adopted an acronym often used by NASA in announcing launch dates: NET, meaning “No Earlier Than.”

    See the full article here.

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  • richardmitnick 5:37 am on November 6, 2014 Permalink | Reply
    Tags: , , , , Dennis Overbye, ,   

    From NYT: “Funding Is Restored for Storied California Observatory” 

    New York Times

    The New York Times

    NOV. 5, 2014

    NYT Dennis Overbye

    A year after the University of California announced that it would phase out all funding for its storied Lick Observatory, sparking fears that the observatory could close if it could not find outside support, the university said on Tuesday that it had changed its mind.

    As Aimée Dorr, provost and executive vice president of the university, and Nathan Brostrom, executive vice president, said in an Oct. 29 letter to the acting director of the observatory, Claire Max of the University of California, Santa Cruz, “We are rescinding our previous requirements that Lick Observatory become self supporting.”

    Lick, which started operations in 1888, is the oldest mountaintop observatory in the West, located on Mount Hamilton, about 30 miles south of San Francisco. In recent years it has played a pivotal role in the discovery of dark energy, which resulted in a Nobel Prize in 2011, and of planets around other stars.

    UCO Lick Shane Telescope
    UCO Lick Shane Telescope interior
    UCO Lick Shane Telescope

    Lick costs the university about $1.3 million a year to operate, money that the university said was needed in a time of declining state support for new ventures like the mighty Keck telescopes it owns with Caltech on Mauna Kea in Hawaii and the even mightier Thirty Meter Telescope, an international project under construction on Mauna Kea.

    Keck Observatory
    Keck Observatory Interior

    TMT Schematic

    Acknowledging widespread interest among astronomers in keeping Lick alive, Provost Dorr and Mr. Brostrom wrote that they had never said they intended to close Lick and that recent budget plans suggested it could continue to operate without wrecking other projects.

    “Indeed,” they wrote, “we see the Lick, Keck and Thirty Meter Telescope Observatories as an integrated ecosystem that can together maintain and grow U.C.’s leadership in astronomy.”

    See the full article here.

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  • richardmitnick 5:10 pm on October 8, 2014 Permalink | Reply
    Tags: , , , , Dennis Overbye,   

    From Dennis Overbye at the New York Times: “How to Make a Black Hole” 

    New York Times

    The New York Times

    On July 2, 1967, a network of satellites designed to detect tests of nuclear weapons recorded a flash of gamma rays coming from the wrong direction — outer space.

    And so it was that human astronomers were tipped to the existence of one of the most violent phenomena of nature. Today, they know that about once a day somewhere in the observable universe, an explosion called a gamma-ray burst occurs, releasing more energy in a few seconds than our galaxy does in a year.

    These magnificent cosmic conflagrations are as far away as they are rare, which is just as well. If one happened nearby, in our own galaxy, we could be swathed with radiation. The closest gamma-ray burst whose distance has been measured happened some 119 million light-years from us, far outside the so-called Local Group, which contains our own Milky Way galaxy. The farthest so far recorded is now 31 billion light-years away, as calculated by the mathematics of the expanding universe; it happened when the universe was only 500 million years old.

    local group
    Local Group

    Gamma-ray bursts are thought to be the final step in the series of transformations by which stars shrink and slump from blazing glory to oblivion, winding up as bottomless deadly dimples in the fabric of space-time — that is to say, as black holes.

    The hierarchy of dead stars goes like this: Stars like the sun, when they run out of thermonuclear fuel, shrink to cinders known as white dwarfs, the size of Earth. Stars more massive than the sun might collapse more drastically and undergo a supernova explosion, blasting newly formed heavy elements into space to enrich future stars, planets and perhaps life, and leaving behind crushed cores known as neutron stars. These weigh slightly more than the sun but are only 12 miles or so in diameter — so dense that a teaspoonful on Earth would weigh as much as Mount Everest.

    Such an explosion, bright enough to be seen in daylight, happened in 1054, Earth time, as told by Chinese astronomers and the ancient inhabitants of Chaco Canyon in what is now New Mexico. That supernova left behind the Crab nebula, a tangle of glowing shreds of gas and a pulsar — a magnetized neutron star spinning 30 times a second, whipping the gas with magnetic fields that make it glow.

    Crab Nebula

    Neutron stars, theorists say, are the densest stable form of matter, but they are not the end of the story. According to theory, too much mass accumulating on a neutron star can cause its collapse into a black hole, an abyss from which not even light can escape. The signature of such a cataclysm would be a gamma-ray burst, astronomers say.

    Colliding neutron stars

    Supercomputer simulations by astronomers led by Luciano Rezzolla of the Institute of Theoretical Physics in Frankfurt have recently showed this would work.

    The simulation, as it unwound over six weeks of supercomputer time at the Max Planck Institute for Gravitational Physics, started with two neutron stars orbiting each other at a distance of 11 miles. That would not be unusual in the universe; most stars are in fact part of double-star systems and several pairs of pulsars orbiting each other are already known. They will eventually collide because such dense, heavy objects lose energy rapidly and spiral together.

    In the case of Dr. Rezzolla’s computation, it took seven milliseconds for tidal forces from the larger star’s gravity to rip apart the smaller star and unwind it into a spiral resembling flaming toothpaste writhing with magnetic fields and begin munching up the gas.

    The excess plasma forms a fat disk around the new black hole, and its magnetic fields, a billion times stronger than those in the sun, align to channel beams of radiation and particles out at the speed of light. The result is a gamma-ray burst visible across the universe, carrying the news of doom — the last astronomers will ever hear of these stars.

    For those two stars, the last bang was the best. Oblivion can be such a lovely sight.

    See the full article here.

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