A map showing the rate of the expansion of the Universe in different directions across the sky based on data from ESA's XMM-Newton, NASA's Chandra and the German-led ROSAT X-ray observatories.

08/04/2020

Astronomers have assumed for decades that the Universe is expanding at the same rate in all directions. A new study based on data from ESA’s XMM-Newton, NASA’s Chandra and the German-led ROSAT X-ray observatories suggests this key premise of cosmology might be wrong.

Konstantinos Migkas, a PhD researcher in astronomy and astrophysics at the University of Bonn, Germany, and his supervisor Thomas Reiprich originally set out to verify a new method that would enable astronomers to test the so-called isotropy hypothesis. According to this assumption, the Universe has, despite some local differences, the same properties in each direction on the large scale.

Widely accepted as a consequence of well-established fundamental physics, the hypothesis has been supported by observations of the cosmic microwave background (CMB). A direct remnant of the Big Bang, the CMB reflects the state of the Universe as it was in its infancy, at only 380 000 years of age. The CMB’s uniform distribution in the sky suggests that in those early days the Universe must have been expanding rapidly and at the same rate in all directions.

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This simulation shows the radiation emitted from a binary black hole system. In principle, we should have neutron star binaries, black hole binaries, and neutron star-black hole systems, covering the entire allowable mass range. In practice, we saw a longstanding 'gap' in such binaries between about 2.5 and 5 solar masses. With the newest LIGO data, that gap seems to disappear.NASA'S GODDARD SPACE FLIGHT CENTER

Ethan Siegel

Mar 20, 2020

On Monday, March 16, 2020, astrophysicist Carl Rodriguez expressed a sentiment echoed by gravitational wave physicists all across the world: NOT NOW LIGO! Just minutes earlier, the LIGO collaboration sent out an alert suggesting that it had just detected another gravitational wave event, the 56th candidate detection since starting up its latest data-taking run in April of 2019. This one appears to indicate the merger of two black holes, like so many others before it.

Unlike most of the others, however, this one might be the nail-in-the-coffin of the idea of a "mass gap" between neutron stars and black holes. Before LIGO turned back on last April, all of its events, combined with otherwise-known neutron stars and black holes, showed two distinct populations: low-mass neutron stars (below 2.5 solar masses) and high-mass black holes (5 solar masses and up). This latest event, however, falls right into the mass gap range, and could demolish the idea once and for all.

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Powerful magnetic and electric fields whip charged particles around, in a computer simulation of a spinning neutron star. Credit: NASA's Goddard Space Flight Center

These stellar remnants are some of the Universe’s most enigmatic objects — and they are finally starting to give up their secrets.

Adam Mann

NATURE NEWS FEATURE 04 MARCH 2020

When a massive star dies in a supernova, the explosion is only the beginning of the end. Most of the stellar matter is thrown far and wide, but the star’s iron-filled heart remains behind. This core packs as much mass as two Suns and quickly shrinks to a sphere that would span the length of Manhattan. Crushing internal pressure — enough to squeeze Mount Everest to the size of a sugar cube — fuses subatomic protons and electrons into neutrons.

Astronomers know that much about how neutron stars are born. Yet exactly what happens afterwards, inside these ultra-dense cores, remains a mystery. Some researchers theorize that neutrons might dominate all the way down to the centre. Others hypothesize that the incredible pressure compacts the material into more exotic particles or states that squish and deform in unusual ways.

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The CHIME radio telescope in British Columbia (pictured) found that a repeating source of radio waves from deep space has a brief window of activity about every 16 days.
CHIME COLLABORATION

By Christopher Crockett
FEBRUARY 7, 2020

A blast of radio waves from deep space appears to be on a 16-day cycle

A periodic flurry of radio waves from some unknown object in deep space could help astronomers figure out what’s triggering similar radio bursts in other galaxies.

Since 2007, researchers have cataloged over 100 fast radio bursts, or FRBs, coming from every direction in the sky. But it’s unknown what causes these radio bursts. Only 10 have been seen to repeat (SN: 8/14/19), and none of those had exhibited any sort of steady tempo — until now.

One of the known repeaters has a relatively brief window of activity about every 16 days, researchers report January 28 at arXiv.org. That means something about the source or its environment is reliably controlling the burst activity, a potential clue to the true nature of these enigmatic objects.

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New subatomic particles could explain a surprisingly large number of decays of particles called kaons seen in the KOTO experiment (detector shown). JAPAN PROTON ACCELERATOR RESEARCH COMPLEX (J-PARC) CENTER

By Emily Conover

Certain extremely rare decays seem to be happening more often than expected

 A little-known type of particle called a kaon may be stepping into the spotlight.

The exotic subatomic particles are attracting attention for their unexpected behavior in an experiment at a Japanese particle accelerator. Rare kaon decays seem to be happening more frequently than expected, according to the KOTO experiment. If the result holds up to further scrutiny, it could hint at never-before-seen particles that would dethrone particle physicists’ reigning theory, the standard model.

There’s still a good chance KOTO’s result will be overturned, says Yuval Grossman of Cornell University. But “there’s the extremely exciting possibility that they see something totally new.”

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Artist's depiction of 'frame-dragging': two spinning stars twisting space and time. Credit: Mark Myers, OzGrav ARC Centre of Excellence.

An international team of astrophysicists led by Australian Professor Matthew Bailes, from the ARC Centre of Excellence of Gravitational Wave Discovery (OzGrav), has shown exciting new evidence for 'frame-dragging'—how the spinning of a celestial body twists space and time—after tracking the orbit of an exotic stellar pair for almost two decades. The data, which is further evidence for Einstein's theory of General Relativity, is published today the journal Science.

More than a century ago, Albert Einstein published his iconic theory of General Relativity—that the force of gravity arises from the curvature of space and time and that objects, such as the Sun and the Earth, change this geometry. Advances in instrumentation have led to a flood of recent (Nobel prize-winning) science from phenomena further afield linked to General Relativity. The discovery of gravitational waves was announced in 2016; the first image of a black hole shadow and stars orbiting the supermassive black hole at the centre of our own galaxy was published just last year.

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An artist’s conception of two black holes entwined in a gravitational tango. Credit: NASA/JPL-Caltech/SwRI/MSSS/Christopher Go

Do supermassive black holes have friends? The nature of galaxy formation suggests that the answer is yes, and in fact, pairs of supermassive black holes should be common in the universe.

I am an astrophysicist and am interested in a wide range of theoretical problems in astrophysics, from the formation of the very first galaxies to the gravitational interactions of black holes, stars and even planets. Black holes are intriguing systems, and supermassive black holes and the dense stellar environments that surround them represent one of the most extreme places in our universe.

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TheOskarKleinCentre

On December 13th, 2019, James Peebles, Nobel Prize in Physics 2019, visited the Oskar Klein Centre and the Department of Physics at Stockholm university to give an informal talk.

Youtube Link

"My thesis advisor and professor of continuing education, Bob Dicke, suggested I look into cosmology. That was 1964. I was uneasy because the empirical basis seemed so slight, but I could think of a few things to analyze after which I imagined I would return to something more substantial. But one thought led to another and then another through my career as the theory and practice of cosmology grew. I will offer thoughts about my experience and the broader lessons to drawn from the establishment of this considerable extension of the reach of natural science. The lessons can be drawn from other branches of science, but I think they are particularly clear in cosmology because this is a conceptually simple subject involving relatively few people up to its transition to Big Science."

Rather than being a beginning, the Big Bang could have been a moment of transition from one period of space and time to another – more of a bounce (Credit: Alamy)

By Patchen Barss 20th January 2020 - BBC Future

The Big Bang is widely accepted as being the beginning of everything we see around us, but other theories that are gathering support among scientists are suggesting otherwise.

The usual story of the Universe has a beginning, middle, and an end.

It began with the Big Bang 13.8 billion years ago when the Universe was tiny, hot, and dense. In less than a billionth of a billionth of a second, that pinpoint of a universe expanded to more than a billion, billion times its original size through a process called “cosmological inflation”.

Next came “the graceful exit”, when inflation stopped. The universe carried on expanding and cooling, but at a fraction of the initial rate. For the next 380,000 years, the Universe was so dense that not even light could move through it – the cosmos was an opaque, superhot plasma of scattered particles. When things finally cooled enough for the first hydrogen atoms to form, the Universe swiftly became transparent. Radiation burst out in every direction, and the Universe was on its way to becoming the lumpy entity we see today, with vast swaths of empty space punctuated by clumps of particles, dust, stars, black holes, galaxies, radiation, and other forms of matter and energy.

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An artist's illustration of two black holes merging and creating ripples in spacetime known as gravitational waves.  (Image: © LIGO/T. Pyle)

By Paul Sutter 6.12.2019

Scientists are on the verge of being able to detect the "memory" left behind by gravitational waves.

Paul M. Sutter is an astrophysicist at The Ohio State University, host of Ask a Spaceman and Space Radio, and author of "Your Place in the Universe." Sutter contributed this article to Space.com's Expert Voices: Op-Ed & Insights.

Gravitational waves slosh throughout the universe as ripples in space-time produced by some of the most cataclysmic events possible.

With facilities like the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo, we can now detect the strongest of those ripples as they wash over the Earth. But gravitational waves leave behind a memory — a permanent bend in space-time — as they pass through, and we are now on the verge of being able to detect that too, allowing us to push our understanding of gravity to the limits.

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Virginia Trimble at the University of California, Irvine, where she has been on the faculty since 1971. (Monica Almeida for Quanta Magazine)

Elizabeth Landau  November 11, 2019

How a young celebrity became one of the first female astronomers at Caltech, befriended Richard Feynman, and ended up the world’s foremost chronicler of the science of the night sky.

Beginning in 1991, Virginia Trimble read every single astronomy article published in 23 different journals. She would then write an annual “year in review” article, which astronomers everywhere used as a window into the rest of the field at large. Her characteristic dry humor came through even in the first installment: “Science, notoriously, progresses amoeba-like, thrusting out pseudopods in unpredictable directions and dragging in the rest of the body after or, occasionally, retreating in disorder.” She stopped in 2007, in part because, with online publishing, there were just too many articles to read.

This endeavor and others have given Trimble a perspective on the past half-century of astronomy that few others could claim.

Stardom was part of Trimble’s early years, and not just because she attended Hollywood High School. In 1962, while still an undergraduate at the University of California, Los Angeles, she achieved her first small measure of fame when Life magazine published an article about her titled “Behind a Lovely Face, a 180 I.Q.” Then in 1963, she became Miss Twilight Zone, the face of a publicity campaign to promote the popular sci-fi show with Rod Serling.

In college she immersed herself in the other kind of stars — the ones in the broader universe — and went on to become one of the first women to earn a doctorate in astrophysics at the California Institute of Technology. While she was there, she befriended Richard Feynman, who paid her $5.50 an hour to pose as a model.

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A black hole (one illustrated) with a mass equal to about 68 suns has been found in the Milky Way, researchers say. That dark mass is much heavier than other similar black holes. (NAOJ)

By Christopher Crockett 28.11.2019

A heavyweight black hole in our galaxy has some explaining to do.

With a mass of about 68 suns, it is far heftier than other stellar-mass black holes (those with masses below about 100 suns) in and around the Milky Way, scientists say. That’s not just a record, it’s also a conundrum. According to theory, black holes in our galaxy that form from the explosive deaths of massive stars — as this one likely did — shouldn’t be heavier than about 25 suns.

The black hole is locked in orbit with a young blue star dubbed LB-1, which sits about 13,800 light-years away in the constellation Gemini, researchers found. Combing through data from the LAMOST telescope in China, Jifeng Liu, an astrophysicist at the Chinese Academy of Sciences in Beijing, and colleagues noticed that LB-1 repeatedly moves toward and away from Earth with great speed — a sign that the star orbits something massive.

With additional observations from telescopes in Hawaii and the Canary Islands, the team mapped out the orbit and deduced that the star gets whipped around by a dark mass roughly 68 times as massive as the sun. Only a black hole fits that description, the team reports November 27 in Nature.

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Report commissioned by the European Physical Society says industries that rely on expertise in physics contribute 12 per cent of EU economic output

By Nicholas Wallace

Industries that rely on physics expertise contribute more to the EU economy than financial services or retail, according to a new study.

A report commissioned by the European Physical Society (EPS) says that in the EU, physics made a net contribution to the economy of at least €1.45 trillion per year – or 12 per cent –which is more than retail (4.5 per cent), construction (5.3 per cent) or financial services (5.3 per cent). Physics-based industries, it says, include electrical, civil and mechanical engineering, as well as computing and other industries reliant on physics research.

The EPS paper comes as EU countries debate how much to spend on Horizon Europe, the EU’s next research programme, which will pump billions into scientific research and technological development. The European Commission wants to spend €94.1 billion on Horizon Europe and the European Parliament wants €120 billion, but some member states, particularly Germany, say the Commission’s proposal for the entire EU budget is too big – meaning Horizon Europe could end up much smaller than scientists had hoped.

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This new and incredibly deep image from Hubble shows the dim and diffuse galaxy NGC 1052-DF4. New research presents the strongest evidence yet that this strange galaxy is basically devoid of dark matter.  NASA/ESA/STScI/S. Danieli et al.

The new research may have dramatic implications for galaxy formation.
By Jake Parks | Published: Friday, October 18, 2019

Astronomers have all but confirmed the universe has at least one galaxy that's woefully deficient in dark matter. The new finding not only indicates that galaxies really can exist without dark matter, but also raises fundamental questions about how such oddball galaxies form in the first place.

The research, posted October 16 on the preprint site arXiv, used Hubble's keen eye to take new, deep images of the ghostly galaxy NGC 1052-DF4 (or DF4 for short). Equipped with fresh observations, the researchers identified the bizarre galaxy's brightest red giant stars (called the Tip of the Red Giant Branch, or TRGB). Because TRGB stars all shine with the same true brightness when viewed in infrared, the only thing that should affect how bright they appear is their distance.

So, by identifying the galaxy's TRGB and using that to determine DF4's distance, the new data essentially confirms the galaxy is located some 61 million light-years away. And according to the researchers, this essentially debunks other studies that claim DF4 is much closer and therefore contains a normal amount of dark matter.

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Scientists have obtained the first image of a black hole, using Event Horizon Telescope observations of the center of the galaxy M87. The image shows a bright ring formed as light bends in the intense gravity around a black hole that is 6.5 billion times more massive than the Sun. This long-sought image provides the strongest evidence to date for the existence of supermassive black holes and opens a new window onto the study of black holes, their event horizons, and gravity. Credit: Event Horizon Telescope Collaboration

https://www.youtube.com/watch?v=3QEPzP58neg&feature=youtu.be

2020 Breakthrough Prize in Fundamental Physics

The Event Horizon Telescope Collaboration

Collaboration Director Shep Doeleman of the Harvard-Smithsonian Center for Astrophysics will accept on behalf the collaboration. The $3 million prize will be shared equally with 347 scientists co-authoring any of the six papers published by the EHT on April 10, 2019, which can be found here. The names are also listed at the bottom of this page.
Citation: For the first image of a supermassive black hole, taken by means of an Earth-sized alliance of telescopes.
Description: Using eight sensitive radio telescopes strategically positioned around the world in Antarctica, Chile, Mexico, Hawaii, Arizona and Spain, a global collaboration of scientists at 60 institutions operating in 20 countries and regions captured an image of a black hole for the first time. By synchronizing each telescope using a network of atomic clocks, the team created a virtual telescope as large as the Earth, with a resolving power never before achieved from the surface of our planet. One of their first targets was the supermassive black hole at the center of the Messier 87 galaxy – its mass equivalent to 6.5 billion suns. After painstakingly analyzing the data with novel algorithms and techniques, the team produced an image of this galactic monster, silhouetted against hot gas swirling around the black hole, that matched expectations from Einstein's theory of gravity: a bright ring marking the point where light orbits the black hole, surrounding a dark region where light cannot escape the black hole's gravitational pull.

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