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DTSTART;VALUE=DATE:20240327
DTEND;VALUE=DATE:20240328
DTSTAMP:20260604T053744
CREATED:20240330T053929Z
LAST-MODIFIED:20241102T104213Z
UID:105208-1711497600-1711583999@www.a3veen.nl
SUMMARY:First Sagittarius A* Event Horizon Telescope Results VII / VIII - publication
DESCRIPTION:After delivering the first images of the event horizon surrounding the Milky Way’s supermassive black hole Sagittarius A* (Sgr A*)\, the Event Horizon Telescope has taken an even deeper look. \nFresh imagery from the Event Horizon Telescope (EHT) collaboration has uncovered strong and organized magnetic fields spiraling from the edge of the supermassive black hole Sgr A*. Seen in polarized light for the first time\, this new view of the monster lurking at the heart of the Milky Way Galaxy has revealed a magnetic field structure strikingly similar to that of the black hole at the center of the M87 galaxy\, suggesting that strong magnetic fields may be common to all black holes. This similarity also hints toward a hidden jet in Sgr A*. The results in two studies were published in The Astrophysical Journal Letters. Scientists unveiled the first image of Sgr A*— which is approximately 27\,000 light-years away from Earth— in 2022\, revealing that while the Milky Way’s supermassive black hole is more than a thousand times smaller and less massive than M87’s\, it looks remarkably similar. This made scientists wonder whether the two shared common traits outside of their looks. To find out\, the team decided to study Sgr A* in polarized light. Previous studies of light around M87’s black hole revealed that the magnetic fields around the black hole giant allowed it to launch powerful jets of material back into the surrounding environment. Building on this work\, the new images have revealed that the same may be true for Sgr A*. \nLinks:\nNew View Reveals Magnetic Fields Around Our Galaxy’s Giant Black Hole \nAgenda – Event Horizon Telescope (EHT)
URL:https://www.a3veen.nl/event/first-sagittarius-a-event-horizon-telescope-results-vii-viii-publication/
CATEGORIES:Astronomie
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20231115
DTEND;VALUE=DATE:20231116
DTSTAMP:20260604T053744
CREATED:20240228T141445Z
LAST-MODIFIED:20240228T141841Z
UID:103424-1700006400-1700092799@www.a3veen.nl
SUMMARY:DoBlackHoleshaveSingularities? - publication
DESCRIPTION:Roy Kerr in a 20 page article published on ResearchGate: there is no proof that black holes contain singularities when they are generated by real physical bodies. \nRoger Penrose claimed sixty years ago that trapped surfaces inevitably lead to light rays of finite affine length (FALL’s). Penrose and Stephen Hawking then asserted that these must end in actual singularities. When they could not prove this they decreed it to be self evident. It is shown that there are counterexamples through every point in the Kerr metric. These are asymptotic to at least one eventhorizon and do not end in singularities. \nLinks:\nWhy does Roy Kerr claim that the Kerr black hole does not contain a singularity? \nKerr disputes singularities in Kerr Black Holes \nRoy Kerr’s recent paper proposes that black holes don’t have singularity. Can someone explain to me his reasoning?
URL:https://www.a3veen.nl/event/doblackholeshavesingularities-publication/
CATEGORIES:Astronomie,Zwart gat
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20231001
DTEND;VALUE=DATE:20231002
DTSTAMP:20260604T053744
CREATED:20231029T145415Z
LAST-MODIFIED:20231029T162930Z
UID:97679-1696118400-1696204799@www.a3veen.nl
SUMMARY:Study finds the Universe is a black hole (kind of) / All objects and some questions - publication
DESCRIPTION:The paper ‘All objects and some questions‘ presents an overview of the thermal history of the Universe and the sequence of objects (e.g.\, protons\, planets\, and galaxies) that condensed out of the background as the Universe expanded and cooled. \nThe authors plot the density and temperature of the Universe as a function of time and the masses and sizes of all objects in the Universe. These comprehensive pedagogical plots draw attention to the triangular regions forbidden by general relativity and quantum uncertainty and help navigate the relationship between gravity and quantum mechanics. How can we interpret their intersection at the smallest possible objects: Planck-mass black holes (“instantons”)? Does their Planck density and Planck temperature make them good candidates for the initial conditions of the Universe? Our plot of all objects also seems to suggest that the Universe is a black hole. The writers explain how this depends on the unlikely assumption that our Universe is surrounded by zero density Minkowski space. \nLinks:\nStudy finds the Universe is a black hole (kind of)
URL:https://www.a3veen.nl/event/all-objects-and-some-questions-publication/
CATEGORIES:Astronomie
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Amsterdam:20230814T080000
DTEND;TZID=Europe/Amsterdam:20230814T170000
DTSTAMP:20260604T053744
CREATED:20230814T165855Z
LAST-MODIFIED:20230814T173236Z
UID:93445-1692000000-1692032400@www.a3veen.nl
SUMMARY:The Sky at Night - Black Holes: Searching for the Unknown (TV BBC Four)
DESCRIPTION:  \nThe Sky at Night is a monthly documentary television programme on astronomy produced by the BBC. \nThe show had the same permanent presenter\, Patrick Moore\, from its first broadcast on 24 April 1957 until 7 January 2013. The latter date was a posthumous broadcast\, which followed Moore’s death on 9 December 2012. This made it the longest-running programme with the same presenter in television history. Many early episodes are missing\, either because the tapes were wiped\, thrown out\, or because the episode was broadcast live and never recorded in the first place. \nBeginning with the 3 February 2013 edition\, the show was co-presented by Lucie Green and Chris Lintott. Since December 2013 Maggie Aderin-Pocock has been a presenter. The programme’s opening and closing theme music is “At the Castle Gate”\, from the incidental music to Pelléas et Mélisande\, written in 1905 by Jean Sibelius\, performed by the Royal Philharmonic Orchestra and conducted by Sir Thomas Beecham. \nThis episode:\n \nThere has never been a more exciting time to study one of the most mysterious phenomena in space. This month\, The Sky at Night team investigate the science of black holes and discover the incredible techniques being used to uncover their secrets\, and even help us answer bigger questions about our universe. \nChris meets with Dr Becky Smethurst at the University of Oxford to learn how a black hole forms from the death of a star. He also investigates whether black holes deserve their menacing portrayal in popular culture. He describes what would happen if we got too close to the event horizon and how black holes might actually play a role in lighting up the universe. \nMaggie explores how scientists are trying to understand more about black holes by meeting Dr Tessa Baker\, who works on LIGO. The Laser Interferometer Gravitational-Wave Observatory is one of the world’s largest physics experiments and is not your usual type of observatory; instead of looking – it listens. The next observation run has just started\, and Maggie learns what they are hoping to find. \nChris meets with Dr James Nightingale\, who has recently discovered one of the largest black holes in space using brand new computational technology and the age-old technique of gravitational lensing. They explore the relationship between black holes and galaxies\, as it is thought that within the centre of every galaxy lies a supermassive black hole. \nWe visit our in-house stargazing expert\, Pete Lawrence\, who shows us how to find a black hole in the sky\, and Saturn at its brightest and best. \nFinally\, George Dransfield visits Dr Silke Weinfurtner at her black hole laboratory\, where they are simulating features of black holes here on Earth. They use fluid systems to perform experiments to try to determine if phenomena we think occur around black holes could actually happen. \nLinks:\nThe Sky at Night
URL:https://www.a3veen.nl/event/the-sky-at-night-black-holes-searching-for-the-unknown-tv-bbc-four/
CATEGORIES:Astronomie,Cultuur,TV
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Amsterdam:20190410T130000
DTEND;TZID=Europe/Amsterdam:20190410T140000
DTSTAMP:20260604T053744
CREATED:20231117T165615Z
LAST-MODIFIED:20240330T160539Z
UID:98769-1554901200-1554904800@www.a3veen.nl
SUMMARY:#EHTBlackHole #BlackHoleDay #RealBlackHole Event Horizon Telescope (EHT)
DESCRIPTION:On April 10th 2019\, the Event Horizon Telescope (EHT) Collaboration will present its first results in multiple simultaneous press conferences around the world\, and many satellite events organized by its stakeholder and affiliated institutions. \nPress conferences will be held simultaneously in Brussels (in English)\, Lyngby (in Danish)\, Santiago (in Spanish)\, Shanghai (in Mandarin)\, Tokyo (in Japanese)\, Taipei (in Mandarin)\, and Washington D.C. (in English). The EHT — a planet-scale array of eight ground-based radio telescopes forged through international collaboration — was designed to capture images of a black hole. In coordinated press conferences across the globe\, EHT researchers revealed that they succeeded\, unveiling the first direct visual evidence of the supermassive black hole in the centre of Messier 87 (M87*) and its shadow. In this image of M87* taken on 11 April 2017 (a representative example of the images collected in a global 2017 EHT campaign)\, the shadow of a black hole is the closest we can come to an image of the black hole itself\, a completely dark object from which light cannot escape. \nThe black hole’s boundary — the event horizon from which the EHT takes its name — is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across. While this may sound large\, this ring is only about 40 microarcseconds across — equivalent to measuring the length of a credit card on the surface of the Moon. Although the telescopes making up the EHT are not physically connected\, they are able to synchronize their recorded data with atomic clocks — hydrogen masers — which precisely time their observations. These observations were collected at a wavelength of 1.3 mm in the 2017 campaign. Each telescope of the EHT produced enormous amounts of data – roughly 350 terabytes per day – which was stored on high-performance helium-filled hard drives. \nThese data were flown to highly specialised supercomputers — known as correlators — at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then painstakingly converted into an image using novel computational tools developed by the collaboration. This image is the average of three different imaging methods after convolving each with a circular Gaussian kernel to give matched resolutions. The image is shown in units of brightness temperature\, \, where S is the flux density\, λ is the observing wavelength\, is the Boltzmann constant\, and Ω is the solid angle of the resolution element. \nLinks:\nFirst Results from the Event Horizon Telescope to be Presented on April 10th \nBrussels: European Comission Youtube Channel \nSantiago: ALMA website \nTaipei: Academia Sinica channel on Youtube \nTokyo: National Astronomical Observatory of Japan channels on Youtube \nWashngton: US National Science Foundation Live Stream \nVerwacht: eerste foto van een zwart gat \nThe physics of black holes (TV On-demand) \nFamous Black Hole Shows Its Wobbly Past in New Movie\n \nFrom black holes to quantum computing – with Marika Taylor \nFirst Sagittarius A* Event Horizon Telescope Results VII / VIII – publication
URL:https://www.a3veen.nl/event/ehtblackhole-blackholeday-realblackhole-event-horizon-telescope-eht/
CATEGORIES:Astronomie
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