I never wrote a book with Roger Penrose. I simply sent him a text titled "The coherent brain" after reading his book "The emperor's new mind" because my ideas were close to his book. He answered within a week with a hard copy letter, partly handwritten, saying that my ideas were "highly interesting" and advicing me to read his new book "Shadows of the mind", which I did. I think I shall make a poster of that 1995 Penrose letter and hang it on a wall.
Tullio

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I never wrote a book with Roger Penrose. I simply sent him a text titled "The coherent brain" after reading his book "The emperor's new mind" because my ideas were close to his book. He answered within a week with a hard copy letter, partly handwritten, saying that my ideas were "highly interesting" ... I think I shall make a poster of that 1995 Penrose letter and hang it on a wall.
Tullio

Hey! Very good!


Here is an excellent interview, in a very apt setting, that gives a far too brief but very good glimpse into the 'depth of discovery' that Penrose has explored:

(YouTube) Roger Penrose - Is Mathematics Invented or Discovered?
wrote:

... Mathematics describes the real world of atoms and acorns, stars and stairs, with remarkable precision. So is mathematics invented by humans just like chisels and hammers and pieces of music? Or is mathematics discovered — always out there, somewhere, like mysterious islands waiting to be found? Whatever mathematics is, will help define reality itself...

Beautifully thoughtful 'stuff'... And beautifully discussed.


Keep searchin'!
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Astronomers caught a black hole slurping up a star like spaghetti
The rare moment could teach us about stellar death.

... In September of 2019, the light from such a doomed encounter reached Earth. An international team of researchers, using a fleet of telescopes from the European Southern Observatory (ESO), monitored the flare—dubbed AT2019qiz—for a six-month stretch as it grew brighter then faded away.

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Wonderful for me especially. Deja Vu even. I had a discussion a few years back--almost an argument with the Mathematics department head at Tennessee State University. The issue was whether Mathematics was the most sublime invention of mankind or whether it was woven into the fabric of reality and just out there waiting to be discovered as one might find the New World.

The LIGO-VIRGO cooperation has registered 39 gravitational wave events in 2019, bringing to total to 50 after the first detection in 2015. Most are due to the merging of two black holes but there is also an event including two neutron stars and one involving a black hole and a neutron star. Those including neutron stars are interesting because they also emit electromagnetic waves which enable to pinpoint the position of the objects.
Tullio

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A NANOGrav team based in Boulder, Colorado, has observed for 12.5 years the radio emission of 45 pulsars received at Arecibo and Green Bank by measuring their times of arrivals. From these observations they deduct the existence of low frequency gravitational waves, which the LIGO and VIRGO interferometers cannot detect. These GW should be emitted by supermassive black holes in the center of active galaxies. The result has been published in Astrophysical Journal Letters. So Arecibo has also contributed to detect gravitational waves.
Tullio

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A NANOGrav team based in Boulder, Colorado, has observed for 12.5 years the radio emission of 45 pulsars received at Arecibo and Green Bank...

Tullio,

Good find! Thanks for that.

Further details are on:

NANOGrav Finds Possible ‘First Hints’ of Low-Frequency Gravitational Wave Background


Fantastic stuff!

Keep searchin',
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

At Einstein@home I have been crunching data on binary gamma ray pulsars provided by NASA Fermi gamma ray observatory in space. Maybe those data could help NANOGrav to find more.
Tullio

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Einstein@home has published an article on the Astrophysical Journal which details the search done by Einstein@home volunteers for continuos gravitational waves, Although the search has been unsuccessful, full merit is given to the volunteers. There is also a video detailing the reasons for this search.
Tullio

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Lots of smaller bangs mean that we have less galactic bio-material?...


Rare black hole and neutron star collisions sighted twice in 10 days
wrote:

... two collisions between a neutron star and a black hole in the space of 10 days.

Researchers predicted that such collisions would occur, but did not know how often.

The observations could mean that some ideas of how stars and galaxies form may need to be revised.

Prof Vivien Raymond, from Cardiff University, told BBC News that the surprising results were fantastic...

... Instead, it may lean towards another suite of theories, which assume that black holes and neutron stars are indeed found alongside each other. These alternative theories imply that stars and galaxies formed in different ways to the picture painted by standard views...

... The production within stars of so-called heavy elements - such as iron, carbon and oxygen - is related to the proportion of black holes and neutron star pairs in the Universe...

Keep searchin',
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Yikes hope the article is not true. :-(

https://scitechdaily.com/black-holes-may-gain-mass-from-the-expansion-of-the-universe-itself/
Black Holes May Gain Mass From the Expansion of the Universe Itself

Over the past 6 years, gravitational wave observatories have been detecting black hole mergers, verifying a major prediction of Albert Einstein’s theory of gravity. But there is a problem — many of these black holes are unexpectedly large. Now, a team of researchers from the University of Hawai?i at M?noa, the University of Chicago, and the University of Michigan at Ann Arbor, have proposed a novel solution to this problem: black holes grow along with the expansion of the universe.

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Yep. How could we have missed that?!

(Then again, the computations are a bit expensive to run unless you expect them to be significant...)


Anton Petrov explains:

Universe Expansion Could Be Causing Black Holes To Grow In Size


Keep searchin'
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

A new method to spot black holes is now in use.

Hidden black hole revealed as it twists and tugs at a nearby star.

Most smaller black holes aren't creating a glow or collision though, so astronomers need to look for less obvious indicators that one is present in a distant star system.

"When they form a system with a star, they will affect its motion in a subtle but detectable way, so we can find them with sophisticated instruments," explains Stefan Dreizler, from the University of Göttingen in Germany, in a statement.

Dreizler is part of an international team that used the European Southern Observatory's Very Large Telescope in Chile to find a black hole in the star cluster NGC 1850 in the Large Magellanic Cloud galaxy, about 160,000 light-years away. It's believed to be the first time a black hole beyond our galaxy has been discovered by noting its influence on a nearby star.

"Similar to Sherlock Holmes tracking down a criminal gang from their missteps, we are looking at every single star in this cluster with a magnifying glass in one hand trying to find some evidence for the presence of black holes but without seeing them directly," says Sara Saracino, from Liverpool John Moores University, who led the research. "The result shown here represents just one of the wanted criminals, but when you have found one, you are well on your way to discovering many others, in different clusters."

Cheers.

Astronomers Spot Two Supermassive Black Holes on a Collision Course
The black holes are closer to Earth, and to each other, than any other known supermassive black hole pair.

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This record-breaking black hole eruption could cover 16 full moons in the sky.

Astronomers have produced a detailed image of a massive eruption from the nearest feeding supermassive black hole that spans the size of 16 full moons in the sky.

The image, capturing radio emissions of material ejected by the black hole at nearly the speed of light, shows gigantic lobes of plasma spreading more than a million light-years away from the center of its home galaxy, Centaurus A.

Centaurus A, some 12 million light-years from Earth, is the fifth-brightest galaxy in the sky as seen from our planet. At its center sits the nearest known actively feeding black hole to our planet, a monster with the mass of 55 million suns. The black hole devours gas, dust and other material in its vicinity, then ejects it in the form of powerful jets that spread far away into intergalactic space, creating the massive bubbles that can be seen in this image....

Cheers.

Supermassive black hole gobbled up a star in the 1980s, and high schoolers helped discover it.

Cheers.

https://www.livescience.com/researchers-calculate-how-many-black-holes

40 quintillion stellar mass black holes in the universe!
That is hard to get your head around.

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Warning, addicted to SETI crunching!
Crunching as a member of GPU Users Group.
GPUUG Website

In the center of most galaxies lies a supermassive black hole. Some of these are actively feeding on the gas and dust around them, expelling excess energy as powerful jets that are seen as quasars across the entire observable Universe. A new study led by astronomers at the Cosmic Dawn Center reviewed this process using new techniques—and the results may change how we think about the diets of these cosmic behemoths.

https://phys.org/news/2022-02-analysis-fundamentally-view-supermassive-black.html
New analysis leads to a fundamentally different view of supermassive black holes

rewrite the books

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Strangely tilted black hole challenges formation theories.

A tilted black hole spinning around a misaligned axis has been discovered in our galaxy, challenging theories of black hole formation.

The black hole and its companion star form a system called MAXI J1820+070, which lies some 10,000 light-years away from Earth. The system was first spotted by NASA's Chandra X-ray Observatory in 2018. But recent optical observations by the Nordic Optical Telescope in the Canary Islands revealed that the black hole behaves in ways that defy astronomers' expectations....

Two Supermassive Black Holes on Track to Collide Will Warp Space and Time.

Some 9 billion light-years away in the universe, two gargantuan black holes are revolving around one another -- and rather ominously. This is a dance that won't last forever. Around 10,000 years from now, the pair will collide. They'll merge into a single deafening abyss with a force immense enough to warp the fabric of space and time with an eruption of ripples.

Each supermassive void is so unfathomably huge, our minds can barely comprehend their heft and reach. They're hundreds of millions of times the mass of our sun, yet quite close together on a relative cosmic scale -- separated by about 50 times the distance between Earth and Pluto. For context, a black hole merely half the size of a golf ball would have a mass equivalent to our entire planet....

Cheers.