# astro: oops? apropos of rapid expansion of trajectories, the nomadic escape propensity of Titan.

As a vision of a fuzzy snooker, << decades of measurements and calculations have revealed that Titan's orbit around Saturn is expanding- meaning, the moon is getting farther and farther away from the planet- at a rate about 100 times faster than expected. The research suggests that Titan was born much closer to Saturn and migrated out to its current distance of 1.2 million kilometers (about 746,000 miles) over 4.5 billion years. >>

<< Titan is expected to gravitationally squeeze Saturn with a particular frequency that makes the planet oscillate strongly, similarly to how swinging your legs on a swing with the right timing can drive you higher and higher. This process of tidal forcing is called resonance locking. Fuller (Jim Fuller) proposed that the high amplitude of Saturn's oscillation would dissipate a lot of energy, which in turn would cause Titan to migrate outward away from the planet at a faster rate than previously thought. >>

<< The resonance locking theory can apply to many astrophysical systems. I'm now doing some theoretical work to see if the same physics can happen in binary star systems, or exoplanet systems, >> Jim Fuller.

Lori Dajose. Titan is migrating away from Saturn 100 times faster than previously predicted. Jun 8, 2020.

https://phys.org/news/2020-06-titan-migrating-saturn-faster-previously.html

Valery Lainey, Luis Gomez Casajus, et al. Resonance locking in giant planets indicated by the rapid orbital expansion of Titan. Nat Astron. doi: 10.1038/ s41550-020-1120-5. Jun 8, 2020.

https://www.nature.com/articles/s41550-020-1120-5   

Also (quasi-stochastic poetry)

1648b - tenuta di rigo della sonda. Notes. Jan 15, 2005.

https://inkpi.blogspot.com/2005/01/1648b-tenuta-di-rigo-della-sonda.html

# s-astro: exploring the sea of ‘noise’ to understand intricacies

<< Rather than trying to filter out the signal “noise” from stars around which exoplanets are orbiting, (AA) studied all of the signal information together to understand the intricacies within its structure >>

Jim Shelton. Searching a sea of ‘noise’ to find exoplanets — using only data as a guide.  Dec. 20, 2016

http://news.yale.edu/2016/12/20/searching-sea-noise-find-exoplanets-using-only-data-guide

Sahil Agarwal, Fabio Del Sordo and John S. Wettlaufer. Exoplanetary Detection by  multifractal spectral analysis. Publ. 2016  Dec.  20, 2016. The  Astronomical  Journal, Volume  153, Number  1;  doi 10.3847/1538-3881/153/1/12

http://iopscience.iop.org/article/10.3847/1538-3881/153/1/12

# s-astro: a Stephen "prophecy" (update): not 1000 but 100 years only to abandon ...

<< Professor Stephen Hawking will present his predictions that the human race only has one hundred years before we need to colonise another planet >>

Tomorrow's World. BBC and partners launch year of science and technology. Date: 02.05.2017     Last updated: 02.05.2017 at 12.48

http://www.bbc.com/corporate2/mediacentre/mediapacks/tomorrows-world

# s-astro: old, very old water

<< As much as half of all the water on Earth may have come from that interstellar  gas  according  to astrophysicists ’ calculations. That means the same liquid we drink and that fills  the  oceans  may be millions  of  years  older  than the  solar  system  itself. >>

Nicholas St. Fleur. The Water in Your Glass Might Be OlderThan the Sun.  April 15, 2016

http://www.nytimes.com/2016/04/16/science/the-water-in-your-glass-might-be-older-than-the-sun.html

L.  Ilsedore  Cleeves ,  Edwin  A.  Bergin ,  et al. The  ancient  heritage  of  water  ice  in  the  solar  system. Science    26 Sep 2014: Vol.  345,  Issue  6204,  pp.  1590-1593 DOI:  10.1126/science.1258055

http://science.sciencemag.org/content/345/6204/1590

# astro: (they) accidentally snap a picture of the beast - lurking in dust - for the first time

<< Astronomers accidentally discovered the footprints of a monster galaxy in the early universe that has never been seen before. Like a cosmic Yeti, the scientific community generally regarded these galaxies as folklore, given the lack of evidence of their existence, but astronomers in the United States and Australia managed to snap a picture of the beast for the first time. >>

<< An open question is exactly how many of them there are. >>

Cosmic Yeti from the dawn of the universe found lurking in dust. University of Arizona. Oct 22, 2019.

https://m.phys.org/news/2019-10-cosmic-yeti-dawn-universe-lurking.html

Christina C. Williams, Ivo Labbe, et al. 

Discovery of a Dark, Massive, ALMA-only Galaxy at z ~ 5–6 in a Tiny 3 mm Survey. The Astrophysical Journal, Volume 884, Number 2. Oct 22, 2019.

https://iopscience.iop.org/article/10.3847/1538-4357/ab44aa   

# s-astro: a wicked list in the dino-killing range; waiting for new entries

<< Throughout its 4.5-billion-year history, Earth has been repeatedly pummelled by space rocks that have caused anything from an innocuous splash in the ocean to species annihilation. >>

<< It may not happen in our lifetime (..) but "the risk that Earth will get hit in a devastating event one day is very high." >>

<< "We are not ready to defend ourselves" against an Earth-bound object (..) "We have no active planetary defence measures.". Rolf Densing.

Mariette Le Roux. Are asteroids humanity's 'greatest challenge'? June 28, 2017

https://m.phys.org/news/2017-06-asteroids-humanity-greatest.html

FonT

Qui una poetica (quasistocastica) sul "ciottolo Apophis"

http://inkpi.blogspot.it/2006/05/2001-il-ciottolo-apophis.html

# astro: so strong concentration of 'dust pebbles' ultimately leads to a collapse

<<  'dust pebbles' are concentrated so strongly by an instability in the solar nebula that their joint gravitational force ultimately leads to a collapse >>

Comet mission reveals 'missing link' in our understanding of planet formation. Oct 25, 2017

https://m.phys.org/news/2017-10-comet-mission-reveals-link-planet.html

Jurgen Blum, Bastian Gundlach, et al. Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles. Monthly Notices of the Royal Astronomical Society, stx2741 doi: 10.1093/mnras/stx2741 Oct 25, 2017

https://academic.oup.com/mnras/article-abstract/doi/10.1093/mnras/stx2741/4564447

# gst: when turbulence is driven by a strongly compressive guide

<< it is not fully understood how shocks drive turbulence, in particular whether shock driving is a more solenoidal (rotational, divergence-free) or a more compressive (potential, curl-free) mode of driving turbulence. >>️

<< Here, (AA) use hydrodynamical simulations of a shock inducing turbulent motions in a structured, multi-phase medium. >>️

<< Using simulations in which a shock is driven into a multi-phase medium with structures of different sizes and Γ<1, (AA) find b∼1 for all cases, showing that shock-driven turbulence is consistent with strongly compressive driving. >>️

Saee Dhawalikar, Christoph Federrath,  et al. The driving mode of shock-driven turbulence. arXiv:2205.14417v1 [astro-ph.GA]. May 28, 2022. 

https://arxiv.org/abs/2205.14417

Also

keywords 'turbulence' in FonT

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

keywords 'turbolento' in Notes 

(quasi-stochastic poetry)

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

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

keyword 'instability' | 'instabilities' in FonT

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

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

keyword 'instabile' in Notes 

(quasi-stochastic poetry)

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

Keywords: gst, turbulence, instability, waves, shock waves

# s-astro: to peer into a black hole

<< By connecting a global array of radio telescopes together to form the equivalent of a giant Earth-sized telescope – using a technique known as Very Long Baseline Interferometry and Earth-aperture synthesis – scientists will peer into the heart of our Milky Way galaxy where a black hole that is 4m times more massive than our sun – Sagittarius A* – lurks. >>

Carole  Mundell. Astronomers  to  peer  into  a  black  hole  for  first  time  with  new  Event Horizon  Telescope.  17 Mars  2017, 16:17  CET

http://theconversation.com/astronomers-to-peer-into-a-black-hole-for-first-time-with-new-event-horizon-telescope-74559

http://www.media.inaf.it/2017/03/24/mission-impossible-per-levent-horizon-telescope/

http://www.huffingtonpost.it/2017/03/27/buco-nero-foto-event-horizon-telescope-_n_15634820.html

more: "quantum gravity" in: http://journals.aps.org/search

FonT: chissa' se modelli formulati per  descrivere metageometrie di buco nero potrebbero, dopo opportuni  adattamenti, descrivere anche specifiche dinamiche al livello macroscopico generate all'interno (e/o al contorno) di enti in reciproca interazione  ...

# gst: apropos of transitions, droplet trajectories during single and collective bursting bubbles

<< Mechanisms of droplet production from bursting bubbles have been extensively studied for single bubbles, but remain sparsely investigated in more complex collective settings. >>️

<< In the collective bubbling experiment, subsurface quasimonodisperse bubbles are rising up to the surface where, depending on the surfactant concentration, they can either merge or assemble in rafts of monodisperse bubbles. Drop trajectories are recorded, analyzed, and shown to exhibit uniquely distinctive features for the different production mechanisms: centrifuge film drops are ejected sideways, and jet drops are ejected vertically. Different single-burst scalings are finally compared to the experimental size-velocity relationships, and reveal that drops coming from collective bubble bursting appear slower and more scattered than when coming from single bursting bubbles. >>️

B. Neel and L. Deike. Velocity and size quantification of drops in single and collective bursting bubbles experiments. Phys. Rev. Fluids 7, 103603. Oct 5, 2022. 

https://journals.aps.org/prfluids/abstract/10.1103/PhysRevFluids.7.103603

Also: 'when a superbubble can generate trains of shock waves'. Mar 6, 2019.

https://flashontrack.blogspot.com/2019/03/gst-astro-when-superbubble-can-generate.html

Also: 'transition', 'droplet', 'droploid', 'bubble', in: https://www.inkgmr.net/kwrds.html

Keywords: gst, transition, drop, droplet, droploid, bubble, collective dynamics,  fluid dynamics

PS: << they can either merge or assemble in rafts of monodisperse bubbles >> ; this is poetry, without unnecessary adjectives, anzicheforse ... FonT. Wed June 14, 2023 16:58 (cest)

# astro: after Florence, the binary nature of the near-Earth asteroid 2017 YE5, as dark as charcoal.

<< Near-Earth asteroid 2017 YE5 was discovered with observations provided by the Morocco Oukaimeden Sky Survey on Dec. 21, 2017. >>

<< On June 24 (..) they were able to confirm that 2017 YE5 consists of two separated objects. By June 26, both Goldstone and Arecibo had independently confirmed the asteroid's binary nature. >>

<< At its closest approach to Earth, the asteroid came to within 16 times the distance between Earth and the moon. >>

<< 2017 YE5 is likely as dark as charcoal. >>

Calla Cofield. Observatories team up to reveal rare double asteroid. Jet Propulsion Laboratory. Jul 13, 2018.

https://m.phys.org/news/2018-07-observatories-team-reveal-rare-asteroid.html  

Also

<< Asteroid Florence, a large near-Earth asteroid, will pass safely by Earth on Sept. 1, 2017, at a distance of about 4.4 million miles, (7.0 million kilometers, or about 18 Earth-Moon distances). Florence is among the largest near-Earth asteroids that are several miles is size; measurements from NASA's Spitzer Space Telescope and NEOWISE mission indicate it's about 2.7 miles (4.4 kilometers) in size. >>

Large asteroid to safely pass Earth on September 1. NASA. Aug 18, 2017.

https://m.phys.org/news/2017-08-large-asteroid-safely-earth-september.html

# 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

# astro: the first picture of a black hole at the heart of galaxy Messier 87.

<< We have taken the first picture of a black hole, (..) This is an extraordinary scientific feat accomplished by a team of more than 200 researchers. (..) We have achieved something presumed to be impossible just a generation ago, (..)  Breakthroughs in technology, connections between the world's best radio observatories, and innovative algorithms all came together to open an entirely new window on black holes and the event horizon. >> Sheperd S. Doeleman

<< This breakthrough was announced today in a series of six papers published in a special issue of The Astrophysical Journal Letters.  >>

<< The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope. Petabytes of raw data from the telescopes were combined by highly specialised supercomputers hosted by the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory. >>

Astronomers Capture First Image of a Black Hole. An international collaboration presents paradigm-shifting observations of the gargantuan black hole at the heart of distant galaxy Messier 87. Apr 10, 2019.

https://eventhorizontelescope.org  

The Event Horizon Telescope Collaboration et al.  First M87 Event Horizon Telescope Results. IV. Imaging the Central Supermassive Black Hole.   2019 ApJL 875 L4

https://iopscience.iop.org/article/10.3847/2041-8213/ab0e85

# s-astro: about Milkomeda wave

<< The  two  celestial  giants  will become  one  and  stars,  planets  and  gas  clouds  will  be  hurled  into  intergalactic  space  by  titanic  gravitational  forces.  Surviving  stars  and planets  will  be  pitched  into  a  jumbled  cloud  flaring  up  with  new  stars  –  floating  into  a  long  future  not  in  the  Milky  Way,  nor Andromeda,  but  a  monstrous  “Milkomeda”  galaxy. >>

Our galaxy’s impossible collision could break gravity. 30 March 2016

https://www.newscientist.com/article/mg23030670-300-how-a-galactic-smashup-could-force-a-rethink-of-gravitys-laws/

# 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

# gst: the three-body problem approach using deep neural networks

AA << show that an ensemble of solutions obtained using an arbitrarily precise numerical integrator can be used to train a deep artificial neural network (..) that, over a bounded time interval, provides accurate solutions at fixed computational cost and up to 100 million times faster than a state-of-the-art solver. >>

Philip G. Breen, Christopher N. Foley,  et al. Newton vs the machine: solving the chaotic three-body problem using deep neural networks. arXiv: 1910.07291v1 [astro-ph.GA] Oct 16, 2019

https://arxiv.org/abs/1910.07291

A neural net solves the three-body problem 100 million times faster. By Emerging Technology from the arXiv. 

Oct 26, 2019. 

https://www.technologyreview.com/s/614597/a-neural-net-solves-the-three-body-problem-100-million-times-faster/

Also

keyword "three" in FonT    

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

keyword "three" in Notes      

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

# astro: a "zombie" star as a homing beacon to detect classes of black holes

<< The research explored whether a dormant white dwarf star-sometimes referred to as a "zombie" star-could reignite if it had a close encounter with an intermediate-mass black hole. >>

<< If the stars align, so to speak, a zombie star could serve as a homing beacon for a never-before-detected class of black holes. >>

<< The stretching phenomena can be very complicated (..) Imagine a spherical star approaching a black hole. As it approaches the black hole, tidal forces begin to compress the star in a direction perpendicular to the orbital plane, reigniting it. But within the orbital plane, these gravitational forces stretch the star and tear it apart. It's a competing effect. >> Rob Hoffman

<< It was exciting to see that the zombie star reignited in each of the close encounter scenarios we looked at, >> Peter Anninos

Nolan O'brien. 'Zombie' stars return from the dead. Lawrence Livermore National Laboratory. Oct 31, 2018.

https://m.phys.org/news/2018-10-zombie-stars-dead.html

Peter Anninos, P. Chris Fragile, et al. Relativistic Tidal Disruption and Nuclear Ignition of White Dwarf Stars by Intermediate-mass Black Holes. The Astrophysical Journal, Volume 865, Number 1. Sep 17, 2018. doi: 10.3847/1538-4357/aadad9.

http://iopscience.iop.org/article/10.3847/1538-4357/aadad9/meta  

# astro: when an unlucky star ventures close enough to a black hole, it spaghettifies ...

<< To be disrupted, an unlucky star must venture close enough to a black hole that gravitational tides exceed the internal gravity that binds the star together. In other words, the difference in the black hole's gravitational pull on the near and far sides of the star, along with the inertial pull as the star swings around the black hole, stretches the star out into a stream. "Basically it spaghettifies," >> James Guillochon

Joshua Sokol. Star-Swallowing Black Holes Reveal Secrets in Exotic Light Shows. August 8, 2018.

https://www.quantamagazine.org/star-swallowing-black-holes-reveal-secrets-in-exotic-light-shows-20180808/

# astro: Tabby' Star, not Aliens there, but (probably) dust

AA << advanced many theories, such as aliens building a Dyson sphere, but most were shot down. The most likely explanation, Boyajian has suggested, is dust >>

Bob Yirka. Tabby's star dims again.
Mar 28, 2018.

https://m.phys.org/news/2018-03-tabby-star-dims.html

http://www.wherestheflux.com/single-post/2018/03/19/tldr-DIPPING

# s-astro: 100 years after ... first tracks of gravitational waves ...

tweet:

https://twitter.com/LIGO/status/697805846726713345

news:

https://www.ligo.caltech.edu/news/ligo20160211

paper:

http://dx.doi.org/10.1103/PhysRevLett.116.061102

Einstein' gravitational waves: first two  papers:

Einstein, A. "Näherungsweise Integration der Feldgleichungen der Gravitation". Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften Berlin. 2016, June. part 1: 688–696.

Einstein, A. "Über Gravitationswellen". Sitzungsberichte der Königlich Preussischen Akademie der Wissenschaften Berlin. 1918,  part 1: 154–167.

http://einstein-annalen.mpiwg-berlin.mpg.de/related_texts/sitzungsberichte

apropos di onde, una rima (quasistocastica) su Maxwell: 1848-onda parametrica, Novembre 29, 2004

http://inkpi.blogspot.it/2004/11/1848-onda-parametrica.html