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December 3, 2021

Simulation shows stars shredded as they get too close to a black hole

I first happened on this article last Sunday before football started.

Sunday mornings are always a good time for me to think different because I'm in an excellent mood, stoked what with about 12 hours of nonstop NFL action upcoming starting with the 1 p.m. games, moving on to the 4:25 p.m. Game of the Week, and finally the 8:20 p.m. nightcap.

But I digress.

As soon as I read the headline (in bold below) of the article, I thought to myself, that's the way I'd like to go: a one-way trip across the event horizon, instantly particle-ized by the black hole's immense gravitational force.

Much better than being "spaced" — as happens with people unfortunate enough to be shoved out the airlock without a spacesuit in shows like "The Expanse" and "Foundation."

See, the bad thing about being spaced is that it's predicted you remain conscious for the 2-3 seconds it takes for you to freeze solid at near absolute zero.

Before updating my advance directive, I'd hoped I would either drop dead during a road race or spontaneously combust, the former being far more likely than the latter.

From Science Alert:

Jaw-Dropping Simulation Shows Stars Shredded as They Get Too Close to a Black Hole

We just got a little more insight into stellar death by black hole.

In a series of simulations, a team of astrophysicists has chucked a bunch of stars at a range of black holes, and recorded what happens.

It's the first study of its kind, the scientists said, that combines Einstein's theory of general relativity with realistic models of the densities of main-sequence stars. The results will help us understand what is happening when we observe the flares of light from distant black holes shredding unfortunate stars.

And the simulations, supporting a paper that was published last year, are also gorgeous as heck.

When a star ventures a little too close to a black hole, things turn violent pretty quickly. The extreme gravitational field of the black hole starts deforming and then pulling the star apart, due to what we call tidal forces — the stretching of one body due to the gravitational pull of another.

When a star gets so close to a black hole that the tidal force results in material being stripped from the star, we call that a tidal disruption event.

Black hole eats star

[A simulation of a star disrupted by a black hole.]

In the worst-case scenario for the star, there's no escape. The disruption is total, and some of the star's material gets slurped down onto the black hole like a spaghetti noodle.

But not every encounter between a black hole and a star ends this way. Some stars have been observed surviving. The simulations, led by astrophysicist Taeho Ryu of the Max Planck Institute for Astrophysics in Germany, were designed to find out what factors contributed to a star's survival.

The team created six virtual black holes, with masses between 100,000 and 50 million times that of the Sun. Each of these black holes then had encounters with eight main-sequence stars, with masses between 0.15 and 10 times that of the Sun.

They found that the main factor that contributed to a star's survival was the initial density of the star. The denser the star, the more likely it is to survive an encounter with a black hole. In the video above, you can see these encounters play out around a supermassive black hole 1 million times the Sun's mass. The stars with the highest density are yellow, and the lowest are blue.

The team also found that partial disruptions occur at the same rate as total disruptions, and the proportion of the star's mass that is lost can be described surprisingly easily using a simple expression.

Future research to fill in the finer details will help model the effects of these encounters, including the heretofore relatively neglected partial disruption events, the researchers said.

This will reveal what can happen to a star after it survives an encounter with a black hole; whether it continues along the main sequence, or turns into a stellar remnant; and if it will continue in orbit around the black hole to meet total disruption at a later date.

The paper accompanying the simulations was published in The Astrophysical Journal in 2020.

December 3, 2021 at 04:01 PM | Permalink | Comments (0)

'Katherine Carlyle' — Rupert Thomson

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This 2015 novel, like all of Thomson's books, is completely different from all the others.

What a fecund fertile mind.

His Wikipedia biography is an adventure story in and of itself.


Above and below, the prologue of "Katherine Carlyle."


I invoked SlowRead©® before I started it, what with rave reviews up front from Philip Pullman ("It's a masterpiece."); James Salter ("This is the fascinating story of Katherine Carlyle, who mysteriously decides that instead of university and a privileged life she will erase her identity and much of her emotions and go untraceably to the most remote settlement of the Russian north."); Lionel Shriver ("Smart, stylish, inventive, and always entertaining. I would read any book that Thomson wrote."); and Rebecca Mead ("What new ways of imagining ourselves and our loves are offered by technologies earlier undreamt of?"), among others.


Thomson sat for a 30-minute radio interview with Georgina Godwin earlier this year.

December 3, 2021 at 02:01 PM | Permalink | Comments (1)

Golden Gate Bridge Safety Net

Net USE 2

The Golden Gate Bridge was built during the years 1933-1937.

December 3, 2021 at 12:01 PM | Permalink | Comments (0)

'me + you'

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From Cool Hunting:

A spectacular display of art and technology, artist and architect Suchi Reddy's "me + you" sculpture bursts with light, color, and collective emotion in the central rotunda of the Smithsonian Institution Arts and Industries Building.

The architecturally significant museum — which opened on the National Mall in Washington, D.C. in 1881 — closed in 2004.

It now reopens with an exhibition called FUTURES, where Reddy's work plays a pivotal role.

Underscoring the glowing, interactive artwork is the concept that our emotions contribute to the world around us.


To understand the shimmering 20-foot-tall work requires knowing how to interact with it.

Visitors to the museum can step up to one of the sculpture's nine mandalas.

When the mandala turns green, say "my future looks…" and add a fourth word of your own choosing that represents how you feel.

Through voice-recognition technology, machine learning, and an algorithm, the final word (and the tone used to convey it) is transformed into a unique explosion of color on the mandala.


After each individual representation ends, the colors all join in the central tower, creating a colorful, collective vision of the hopes and dreams of all participants.

"It's the work of so many talented people — a labor of love and passion on the part of everyone involved," said Reddy.

"The technology team at Amazon Web Services helped us with the backend and all of the information processing, as well as the AI and machine learning. My own tech team helped me create all of the visual code that overlays the patterns on the information that we get back from the machine learning data. My fabrication team at Bednark Studios helped me build this cloud sculpture that has thousands of acrylic tubes and nine mandalas, each of which has 1,600 LEDs hand-soldered within."


Reddy's mission statement has long been "form follows feeling."

As she explained to us, "We affect everyone and everything by how we feel and what we put into the world around us. Emotions bind us. They are a powerful medium through which we can affect change. That's why I want this sculpture to be something that helps people be self-aware and see how they can contribute to everyone else's vision for the future."

FUTURES is part of the Smithsonian's 175th anniversary programming.

For those can't make it to the museum before July 2022, Reddy worked with Amazon Web Services and Hovercraft Studio to bring "me + you" online (soundtracked with work from Sacha Mendel).


December 3, 2021 at 10:01 AM | Permalink | Comments (0)

What is it?


Answer here this time tomorrow.

Hint: smaller than a bread box.

Another: moving parts.

A third: no camera.

Also in Sand:


December 3, 2021 at 08:01 AM | Permalink | Comments (1)

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