# gst: dynamics of pulsating spheres orbiting black holes.

AA << study the chaotic dynamics of spinless extended bodies in a wide class of spherically symmetric spacetimes, which encompasses black-hole scenarios in many modified theories of gravity. (They) show that a spherically symmetric pulsating ball may have chaotic motion in this class of spacetimes. >>

AA << use Melnikov's method to show the presence of homoclinic intersections, which imply chaotic behavior, as a consequence of (their)  assumption that the test body has an oscillating radius. >>

Fernanda de F. Rodrigues, Ricardo A. Mosna, Ronaldo S. S. Vieira. Chaotic dynamics of pulsating spheres orbiting black holes. arXiv: 2409.14667v1 [gr-qc]. Sep 23, 2024.

https://arxiv.org/abs/2409.14667

Also: black hole, in https://www.inkgmr.net/kwrds.html 

Keywords: gst, black hole, homoclinic orbit, chaos, transition

# astro: black hole portraits will become more frequent

<< This year marks the fifth anniversary of the release of the first-ever image of a black hole, which revealed the glowing doughnut of the supermassive black hole called M87*. The research team that produced the image—the Event Horizon Telescope (EHT) Collaboration—recently released a second image of that same black hole, which lies 55 million light years from Earth (..). This image comes from an updated version of the EHT and confirms key features of the black hole while also revealing changes over time in the pattern of light emanating from the disk surrounding the object. Starting with this release, the collaboration expects to issue increasingly frequent updates in support of the newly developing field of black hole imaging. >>️

<< “Producing the first image of M87* was a herculean effort and involved creating, testing, and verifying many different schemes and approaches to analyzing and interpreting the data,” says Princeton University astrophysicist Andrew Chael, a member of the EHT Collaboration. “Now we are beginning to transition to a point where we understand our instrument and our analysis frameworks really well, so I think we are going to be releasing results a lot more quickly.” >>

️

Katherine Wright. Black Hole Portraits Will Become More Frequent. Physics 17, 43. Mar 15, 2024. 

https://physics.aps.org/articles/v17/43

Kazunori Akiyama, Antxon Alberdi, et al. The persistent shadow of the supermassive black hole of M 87. 

I. Observations, calibration, imaging, and analysis⋆ The Event Horizon Telescope Collaboration. Astron. Astrophys. 681, A79 (2024).

https://www.aanda.org/articles/aa/full_html/2024/01/aa47932-23/aa47932-23.html

Also: astrophysics, black hole, in https://www.inkgmr.net/kwrds.html 

Keywords: astrophysics, black hole

# gst: the fascinating possibility of two black holes masquerading as one.

<< a pair of black holes whose mutual attraction is balanced by the cosmic expansion would look the same to a distant observer as a single isolated black hole. >>

Oscar J.C. Dias and coll. << point out that when the black holes are allowed to rotate, it is possible that their spin interaction may stabilize the solutions. This raises the fascinating possibility of having an isolated pair of solar-mass black holes in our Universe, balancing happily a few hundred light years apart and impossible to distinguish from a single black hole from far away. >>

<< If these black holes are set up in precisely the correct way, they sit in an unstable equilibrium, akin to a pen balanced on its pointed end. Any disturbance will ruin this perfect balance. >>

Toby Wiseman. Two Black Holes Masquerading as One. Physics 16, 164. Sep 25, 2023. 

https://physics.aps.org/articles/v16/164

Oscar J. C. Dias, Gary W. Gibbons, et al. Static Black Binaries in de Sitter Space. Phys. Rev. Lett. 131, 131401. Sep 25, 2023.

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.131401

Also: black hole, astrophysics, in: https://www.inkgmr.net/kwrds.html 

Keywords: gst, black hole, astrophysics

# gst: another way for the evaporation of a black hole

<< The quantum fluctuations that pervade empty space spontaneously give birth to pairs of particles and antiparticles. Ordinarily, these pairs annihilate so promptly that their existence is virtual. But a powerful field can pull a pair’s members apart for long enough that their existence becomes real. Now (AA) have proposed that particle pairs can be brought into existence by the immense gravitational tidal forces around a black hole (..).>>

<< If the vacuum is stable, all pairs that are created are also destroyed. But a strong field destabilizes the vacuum, makes some paths more likely than others, and leads to a deficit of pairs that recombine. The deficit is balanced by a net outflow of real particles, which, in the case of a black hole’s gravitational field, leads to the black hole’s eventual evaporation. >>️

Charles Day. Another Way for Black Holes to Evaporate. Physics 16, s77. Jun 2, 2023. 

https://physics.aps.org/articles/v16/s77

Michael F. Wondrak, Walter D. van Suijlekom, Heino Falcke. Gravitational Pair Production and Black Hole Evaporation. Phys. Rev. Lett. 130, 221502. Jun 2, 2023. 

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.130.221502

Also:  'black hole', in https://www.inkgmr.net/kwrds.html

Keywords: gst, black hole, astrophysics

# life: a proposito di bizzarri scenari, qui un ipotetico scenario22 dipinto dal reale ...

img: Congo Square, New Orleans, Louisiana (wikipedia.org)

In definitiva qui si configurerebbe un - intrigante assai - scenario che, grosso modo, si potrebbe sinteticamente 'dipingere' in questi termini: 

(i) entità tre palle destrogire, animate aciclicamente da interazioni attrattive- repulsive a causa di già a suo tempo disvelate pulsioni neuro cognitive arcaiche, riconducibili a visioni neuro predatorie CTZ estreme, perciò ipoteticamente (si fa per dire) a-priori ad esiti immediati e in prospettiva drammaticamente lesivi- autolesivi; 

(ii) entità tre palle levogire, animate da analoghe pulsività, purtuttavia in.forme  tenui, in modalità sottotraccia, frenate da feed-back a modalità allosterica, ombreggiate, stemperate, diluite, discrete, timidamente celate, talvolta fantasmatiche perfino, quasi ma non del tutto mai silenti, perciò anch'esse a tutti gli effetti operative, sebbene a dinamiche più fluide, lente, meno dirompenti rispetto alle destrogire; 

(iii) entrambe l'Entità destrogire e levogire animat(t)rici,  generat(t)rici di dinamiche bi-multi-forcate, transeunti, con picchi di improvvisi aciclici burst ad effetti RAG-time diretti e inversi;

(iv) lo scenario al contorno e forse anche all'interno, nei vari specifici contesti, riconducibile grosso modo alla formazione aciclica di ipotetici buchi neri non inerti, caratterizzati da aciclicità in compressione e dilatazione - come fossero fisarmoniche - animati (in perpetuo?) da multi vortici in ingresso e in uscita;

Non so se basti compulsare un manuale delle funzioni speciali per formalizzare in qualche adatto topo-modo questo pulsatile multi scenario, purtuttavia assolutamente intrigante ... 

Qui una AI operativa nella formalizzazione di analogie potrebbe modellizzare, forse ... (e.g. https://flashontrack.blogspot.com/2021/08/aibot-mechanism-of-analogy-could-be.html )

Quello che appare evidente è la complessità d'insieme, un bizzarro dipinto, uno scenario dinamico che, al confronto, le storiche danze in Congo Square potrebbero sembrare semplici, ordinate coreografie ... queste, rispetto a quelle, delle topo-forme  'primitive', per dire ed anzicheforse.

In sintesi, i riferimenti (ovviamente generici) del bizzarro scenario: 

(:) buco nero con vortici 

https://flashontrack.blogspot.com/2022/09/astro-black-holes-as-q-ball-type.html

(:) scenari generati da 3 palle 

(a)

https://flashontrack.blogspot.com/2017/10/gst-more-on-three-body-problem-695.html  

(b)

https://flashontrack.blogspot.com/search?q=three-body

(:) effetti RAG-time (RAG: Ralph, Al, George) 

(a) (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=rag   

(b)

https://flashontrack.blogspot.com/search?q=rag

(:) pulsioni predatorie supportate / giustificate da visioni neuro- post- CTZ nelle modalità arcaiche oppure friendly 

https://flashontrack.blogspot.com/2019/06/brain-immagini-ctz-cicliche.html

(:) Congo Square, jazz 

(a)

https://en.m.wikipedia.org/wiki/Congo_Square   

(b)

https://flashontrack.blogspot.com/search?q=jazz   

(c) (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=jazz

(:) approccio Bertalanffy 

( https://it.m.wikipedia.org/wiki/Ludwig_von_Bertalanffy ) al reale 

https://flashontrack.blogspot.com/search?q=gst

(:) un bizzarro tracciatore 

https://flashontrack.blogspot.com/2022/10/life-proposito-di-transizioni-un.html

Anche

"Amico, qualunque cosa suonerai ... "

(a) (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=jelly+roll  

(b)

https://flashontrack.blogspot.com/search?q=jelly+roll

Keywords: life, gst, Congo Square, jazz, Jelly Roll, transition, three-body, RAG, CTZ, black hole, bizarre tracker

# life: apropos of quasi-stochastic (bizarre) landscapes in high-dimension, a case of double RAG-time inside a black hole with vortices

Here a hypotetical bizarre scenario of coexistence of double RAG-time (RAG: Ralph, Al, George) inside a black hole with vortices:

(1) 

Maurizio Belpietro.Sorprese in vista. Occhio alla strana coppia Conte D'Alema. La verità. anno vii n 258 pg 1. 19 set 2022.

https://www.laverita.info/dalema-conte-2658304063.html

(2) 

Andrea Pertici. Un soccorso centrista alla maggioranza dei due terzi?  

huffingtonpost.it. 18 Set 2022  17:08

https://www.huffingtonpost.it/blog/2022/09/18/news/un_soccorso_centrista_alla_maggioranza_dei_due_terzi-10239275/

Also

keyword 'RAG' in Notes

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=rag

keyword 'RAG' in FonT

https://flashontrack.blogspot.com/search?q=rag

black holes (as Q-ball-type saturons) could admit multi-vortex dynamics.

FonT. Sep 19, 2022.  

https://flashontrack.blogspot.com/2022/09/astro-black-holes-as-q-ball-type.html

PS: really intriguing the image of a black hole with vortices ...

Keywords: life, jazz, RAG-time, RAGtime, black hole, vortex, vortices, vortexes, vorticity

# astro: black holes (as Q-ball-type saturons) could admit multi-vortex dynamics

<< Theoretical physicists argue that black holes admit vortex structures >>

Img << Sketch of a black hole endowed with multiple vortices. Colors denote the orientation, with the associated trapped magnetic field lines in black. Credit: Dvali et al. >>️

<< Recently, a new quantum framework for black holes, namely in terms of Bose-Einstein condensates of gravitons (the quanta of gravity itself), has been introduced, (..) Up until our article was published, rotating black holes have not been thoroughly studied within this framework. However, they might not only exist, but also be the rule rather than the exception. >> Florian Kühnel. 

️

Ingrid Fadelli. Theoretical physicists argue that black holes admit vortex structures. Phys.org. Sep 09, 2022. 

https://phys.org/news/2022-09-theoretical-physicists-black-holes-vortex.html

AA << argue that black holes admit vortex structure. This is based both on a graviton-condensate description of a black hole as well as on a correspondence between black holes and generic objects with maximal entropy compatible with unitarity, so-called saturons. (They) show that due to vorticity, a Q-ball-type saturon of a calculable renormalizable theory obeys the same extremality bound on the spin as the black hole. Correspondingly, a black hole with extremal spin emerges as a graviton condensate with vorticity. (..) Next, (AA) show that in the presence of mobile charges, the global vortex traps a magnetic flux of the gauge field. This can have macroscopically observable consequences. >>

️

Gia Dvali, Florian Kuhnel, Michael Zantedeschi. Vortices in Black Holes. Phys. Rev. Lett. 129, 061302. Aug 3, 2022.  

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.129.061302

Also

keyword 'black hole' in FonT  

https://flashontrack.blogspot.com/search?q=black+hole

Keywords: astro, astrophysics, black hole, rotating black hole, vortex, vorticity

# life: a proposito di vaticini ...

a proposito di vaticini (dal lat.  vates «vate» e canĕre «cantare» )...

Mr. Mario Draghi, la simmetria rifiutata ... 

Simmetrico, purtuttavia caotico. FonT. 19 luglio 2019.

https://flashontrack.blogspot.com/2019/07/life-simmetrico-purtuttavia-caotico.html

Anche

Be careful ... by Potus Joe. FonT. 11 maggio 2022. 

https://flashontrack.blogspot.com/2022/05/life-be-careful-by-potus-joe.html

Anche

Eight new echoing black hole binaries (in Milky Way). FonT. 25 giugno 2022. 

https://flashontrack.blogspot.com/2022/06/astro-eight-new-echoing-black-hole.html

Anche

non saprei dire il perchè ma le vicende governative di Mr Mario Draghi mi hanno fatto ricordare le 'bizzarre visioni' degli Artisti Aldo, Giovanni e Giacomo nell'episodio 'Il Conte Dracula' ... 

(1)   

https://youtu.be/gZNBR4YTSLs

(2)   

https://youtu.be/m9uRj9fV-i4

Keywords: symmetry, chaos, black hole, Mario Draghi, Gov

# gst: apropos of prolate- oblate spheroid transition, the chaotic behavior of a spinless entity around a black hole.

AA << investigate the long-term orbital dynamics of spinless extended bodies in Schwarzschild geometry, and show that periodic deviations from spherical symmetry in the shape of a test body may trigger the onset of chaos. (AA) do this by applying Dixon's formalism at quadrupolar order to a nearly spherical body whose shape oscillates between a prolate and an oblate spheroid. The late-time chaotic behavior is then verified by applying Melnikov's method. >>️

Ricardo A. Mosna, Fernanda F. Rodrigues, Ronaldo S. S. Vieira. Chaotic dynamics of a spinless axisymmetric extended body around a Schwarzschild black hole. arXiv: 2207.04341v1 [gr-qc]. Jul 9, 2022. 

https://arxiv.org/abs/2207.04341

Phys. Rev. D 106, 024016 (2022). 

https://doi.org/10.1103/PhysRevD.106.024016

Also - Oblate and Prolate Spheroid.  

<< The shape of the earth is that of a round ball or sphere slightly flattened at two opposite sides. Such a body is termed a spheroid. There are two kinds of spheroids-oblate and prolate; the former as the shape of an orange, the latter that of a lemon.  >>️

Oblate and Prolate Spheroid.  

https://etc.usf.edu/clipart/30500/30587/spheroid_30587.htm

img    https://etc.usf.edu/clipart/30500/30587/spheroid_30587_sm.gif

Also

keyword 'transition' in FonT: 

https://flashontrack.blogspot.com/search?q=transition

keyword 'transizione' | 'transition' in Notes (quasi-stochastic poetry): 

https://inkpi.blogspot.com/search?q=transizione

https://inkpi.blogspot.com/search?q=transition

Keywords: gst, spheroid, behavior, chaos, transition, black hole

# astro: eight new echoing black hole binaries (in Milky Way)

<< Scattered across our Milky Way galaxy are tens of millions of black holes—immensely strong gravitational wells of spacetime, from which infalling matter, and even light, can never escape. Black holes are dark by definition, except on the rare occasions when they feed. As a black hole pulls in gas and dust from an orbiting star, it can give off spectacular bursts of X-ray light that bounce and echo off the inspiraling gas, briefly illuminating a black hole's extreme surroundings. >>

<< In a study appearing (..) in the The Astrophysical Journal, (AA) report (..) eight new echoing black hole binaries in our galaxy. Previously, only two such systems in the Milky Way were known to emit X-ray echoes. >>️

 << Kara (Erin Kara) and her colleagues are using X-ray echoes to map a black hole's vicinity, much the way that bats use sound echoes to navigate their surroundings. (..)  As a side project, Kara is working with MIT education and music scholars, Kyle Keane and Ian Condry, to convert the emission from a typical X-ray echo into audible sound waves. >>️️

Jennifer Chu. Search reveals eight new sources of black hole echoes. MIT.  May 2, 2022. 

https://phys.org/news/2022-05-reveals-sources-black-hole-echoes.html

https://youtu.be/iIeIag2Ji8k

Jingyi Wang, Erin Kara, et al. The NICER "Reverberation Machine": A Systematic Study of Time Lags in Black Hole X-Ray Binaries. ApJ. 930, 18. May 2, 2022. 

https://iopscience.iop.org/article/10.3847/1538-4357/ac6262

Also

keyword 'black hole' in FonT

https://flashontrack.blogspot.com/search?q=black+hole

keyword 'waves' in FonT

https://flashontrack.blogspot.com/search?q=waves

keyword 'onda' in Notes 

(quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=onda

Keywords: astro, black hole, echoes, waves

# gst: apropos of a immaginary transition (with a tipping point), which simulates the chaotic interactions of three black holes.

<< The interactions between three bodies such as stars or planets or black holes cannot be predicted with an elegant formula. Moerman (Arend Moerman) therefore used a computer that calculates what happens for a short period of time and then uses the result for the next period of time. >>

AA << varied the masses of the three interacting black holes. They started with one solar mass and went up to a billion times the mass of the sun. >>

<< Around ten million solar masses, there appeared to be a tipping point. In the simulations, black holes that are lighter than about ten million solar masses mostly eject each other through a gravitational slingshot. Black holes heavier than about ten million solar masses start to merge. First, two black holes merge. The third black hole will follow later. The black holes merge because they lose kinetic energy and that is because they emit gravitational waves. >>

<< Arend's work (..) has led to a new understanding of how black holes become supermassive. In the simulations, we see that heavy black holes no longer endlessly move around each other, but that, if they are heavy enough, they collide pretty much instantly. >> Simon Portegies Zwart. 

Simulating chaotic interactions of three black holes. Netherlands Research School for Astronomy. Oct 20, 2021. 

https://phys.org/news/2021-10-simulating-chaotic-interactions-black-holes.html

Tjarda C. N. Boekholt, Arend Moerman, Simon F. Portegies Zwart. Relativistic Pythagorean three-body problem. Phys. Rev. D 104, 083020. 14 Oct 14,  2021. 

https://journals.aps.org/prd/abstract/10.1103/PhysRevD.104.083020

Also

more on the three-body problem (695 families of collisionless orbits). FonT. Oct 16, 2017. 

https://flashontrack.blogspot.com/2017/10/gst-more-on-three-body-problem-695.html

keyword 'black hole' | 'astro' in FonT

https://flashontrack.blogspot.com/search?q=black+hole

https://flashontrack.blogspot.com/search?q=astro

keyword 'transition' | 'transitional' in FonT

https://flashontrack.blogspot.com/search?q=transition

https://flashontrack.blogspot.com/search?q=transitional

keyword 'transition' | 'transizion*' in Notes (quasi-stochastic poetry)

https://inkpi.blogspot.com/search?q=transition

https://inkpi.blogspot.com/search?q=transizione

https://inkpi.blogspot.com/search?q=transizioni

keywords: gst, black hole, three-body problem, transition, chaos, chaotic interaction, tipping point.

# gst; apropos of hair that can be combed, some perturbation fields, along the event horizon of extreme black holes, seem to evolve in time indefinitely

 <<  black holes can be fully characterized by only three physical quantities: their mass, spin and charge. Since they have no additional "hairy" attributes to distinguish them, black holes are said to have "no hair"—Black holes of the same mass, spin, and charge are exactly identical to each other. >> 

AA << discovered that a special kind of black hole violates black hole uniqueness, the so-called "no hair" theorem. Specifically, the team studied extremal black holes—holes that are "saturated" with the maximum charge or spin they can possibly carry. They found that there is a quantity that can be constructed from the spacetime curvature at the black hole horizon that is conserved, and measurable by a distant observer. Since this quantity depends on how the black hole was formed, and not just on the three classical attributes, it violates black hole uniqueness. This quantity constitutes "gravitational hair" and potentially measurable by recent and upcoming gravitational wave observatories like LIGO and LISA. >>

<< even though external perturbations of extreme black holes decay as they do also for regular black holes, along the event horizon certain perturbation fields evolve in time indefinitely. >>

<< The uniqueness theorems assume time independence. But the Aretakis phenomenon explicitly violates time independence along the event horizon. This is the loophole through which the hair can pop out and be combed at a great distance by a gravitational wave observatory, >> Lior Burko.

Extreme black holes have hair that can be combed. Theiss Research. Jan 26, 2021.

https://phys.org/news/2021-01-extreme-black-holes-hair.html

Lior M. Burko, Gaurav Khanna, Subir Sabharwal. Scalar and gravitational hair for extreme Kerr black holes. Phys. Rev. D 103, L021502. Jan 26, 2021.

https://journals.aps.org/prd/abstract/10.1103/PhysRevD.103.L021502  

# astro: apropos of elusive predators ... the mid-sized mass black hole

<< Astronomers have found the best evidence for the perpetrator of a cosmic homicide: a black hole of an elusive class known as "intermediate-mass," which betrayed its existence by tearing apart a wayward star that passed too close. >>

<< These so-called intermediate-mass black holes (..) are a long-sought "missing link" in black hole evolution. >>

Claire Andreoli. Hubble finds best evidence for elusive mid-sized black hole. NASA's Goddard Space Flight Center. Mar 31, 2020

https://m.phys.org/news/2020-03-hubble-evidence-elusive-mid-sized-black.html

Dacheng Lin, Jay Strader, et al.  Multiwavelength Follow-up of the Hyperluminous Intermediate-mass Black Hole Candidate 3XMM J215022.4−055108. ApJL 892 L25. Mar 31, 2020

https://iopscience.iop.org/article/10.3847/2041-8213/ab745b

# astro: test the 'no-hair' hypothesis on coalescent black holes (at the ~ 10% or ~ 20% levels)

<< Agreement between the postinspiral measurements of mass and spin and those using the full waveform supports the hypothesis that the GW150914 merger produced a Kerr black hole, as predicted by general relativity, and provides a test of the no-hair theorem at the ∼10% level. An independent measurement of the frequency of the first overtone yields agreement with the no-hair hypothesis at the ∼20% level.  >>

Maximiliano Isi, Matthew Giesler, et al. Testing the No-Hair Theorem with GW150914. Phys. Rev. Lett. 123, 111102. Sep 12, 2019.    https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.111102

Synopsis: Hunting for Hair on Coalescing Black Holes. A fresh look at data from the first detected black-hole merger supports the “no hair” theorem.  Sep 12, 2019.   https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.123.111102

'No-hair' theorem   https://en.m.wikipedia.org/wiki/No-hair_theorem

Kerr black hole   https://en.m.wikipedia.org/wiki/Rotating_black_hole