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Do you know black holes devour stars?#61 Options
Ashwin Joshi
Posted: Wednesday, January 29, 2020 9:16:17 AM

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At the center of nearly every galaxy lies a monster, a giant black hole millions or even billions of times heavier than the Sun. Some, known as quasars or active galactic nuclei, shine brightly from across the universe as they continuously devour surrounding gas.




Source: Sciencemag
Islami
Posted: Wednesday, January 29, 2020 10:46:31 AM
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Grand symbolic picture, Ashwin.

Beyond imagination.
hedy mmm
Posted: Wednesday, January 29, 2020 11:07:10 AM

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Ashwin Joshi wrote:
At the center of nearly every galaxy lies a monster, a giant black hole millions or even billions of times heavier than the Sun. Some, known as quasars or active galactic nuclei, shine brightly from across the universe as they continuously devour surrounding gas.

————
Mind boggling, to say the least and humbling...

There are so many of Albert Einstein‘s theories that seemed so far fetched, especially of Black Holes. I found this quote: “Einstein’s ideas about space & time still hold as the best description yet of how gravity works—gravity results from how mass warps space & time—the greater an objects mass the stronger is gravitational pull.” Astronomers are finally acknowledging that he was right.

He once said in an interview that, "Science without religion is lame, religion without science is blind...God is a mystery. But a comprehensible mystery. I have nothing but awe when I observe the laws of nature. There are not laws without a lawgiver.”

Your thread brought to mind one of my favorite tag lines: "We live on a blue planet that circles around a ball of fire next to a moon that moves the sea, and you don't believe in miracles?”

Awesome thread Ashwin Joshi!

hedy
papo_308
Posted: Wednesday, January 29, 2020 12:34:12 PM
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It's awesome, but a little misleading because the title of the thread (speaking of devouring stars) is inconsistent with the text (speaking of devouring gas).
It's from this article https://www.sciencemag.org/news/2020/01/black-holes-caught-act-swallowing-stars and the first paragraph says

At the center of nearly every galaxy lies a monster, a giant black hole millions or even billions of times heavier than the Sun. Some, known as quasars or active galactic nuclei, shine brightly from across the universe as they continuously devour surrounding gas. But most are dormant, lurking invisibly for thousands of years—until a star passes too close and is ripped to shreds. That triggers a monthslong tidal disruption event (TDE), which can shine as brightly as a supernova.

So, devouring a star doesn't happen so often as constant devouring of gas and it's a much more dramatic event.

Sorry, I didn't want to be nitpicking, only to make clear the difference between the two events.
Both are really monstrous, no doubt.
Islami
Posted: Wednesday, January 29, 2020 11:05:48 PM
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Some stars are made of gas only.
thar
Posted: Wednesday, February 19, 2020 2:39:13 PM

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I always have a bit of an issue with the way black holes are depicted as 'eating' or devouring' matter as if there is some special 'suction' going on. It is still just gravity. Stuff orbits a body and as its orbit decays it falls in. A black hole isn't devouring stars any more than the sun is devouring Earth or the Earth is devouring the moon - or me. It is all just gravity. Black holes just have more of it, because they are more massive.
What happens as objects get very close - event horizon, escape velocity, all that - that gets a bit weird but the mass itself just exerts gravitational force just like any other mass.

Not trying to downplay your point, Ashwin - this is just a bugbear of mine that they are sometimes depicted as 'sucking' you in by some special black hole physics. But no more than the moon is being 'sucked in' by the Earth.


I just saw an article - an obit on a British astronomer. Didn't know where to put it but in fact this thread seems very apt - just enjoying sharing information.

What makes her so special to me is that she was not some high-flying school > university > research career trajectory. A real story about going after what you are passionate about!
Even if you are on a trainee management programme in Topshop. (For those that don't know, that is a high street fashion chain).

Quote:

Broadcaster and astronomer Heather Couper has died at the age of 70.

Dr Couper appeared on the BBC's Blue Peter and The Sky At Night programmes, as well as presenting and producing acclaimed science documentaries.

She also hosted radio series including the BBC World Service's long-running Seeing Stars and BBC Radio 4's Cosmic Quest and Starwatch.

Her best friend and business partner, Nigel Henbest, said she had died on Wednesday after a short illness.

She had been a "charismatic... and passionate communicator of science", he said.

"She got people really excited about the Universe and about space - that was her love, her passion in life."

She was a regular on TV and radio from the 1980s
Born in 1949, she fell in love with astronomy as a child and recalled a day, in 1968, when she had realised astronomy was not just "for shambolic old men in tweed jackets any more".

She went home and wrote in her diary: "I want to help knowledge. I want to make known and publicise science."

So she left her management trainee job at Top Shop to become a research assistant at the Institute of Astronomy in Cambridge.

Her big break came when she was asked to appear as a guest on Sir Patrick Moore's The Sky At Night.

Sir Patrick later recalled: "Of course, she wrote to me when she was a little girl and said, 'Is there any future for me in astronomy?' And I said, 'Of course there is.' And I tried to give her a hand."


She also presented the 1981 ITV children's series Heavens Above and, in 1984, became the first female president of the British Astronomical Association.

Four years later, she co-founded a film and TV production company, then, in 1993, took up the chair of astronomy at Gresham College, a post previously held by Sir Isaac Newton and Sir Christopher Wren.

She and Dr Henbest co-wrote dozens of books as well as monthly astronomy columns for the Independent, the last of which was published on 6 February.

The pair even applied to be the first British astronauts, Dr Couper told the Guardian in 1993, but were quickly rejected.

"They wanted someone technologically on the ball, someone who would know what buttons to press in an emergency," she said.

"If something blew up, I would think, 'Oh Christ! What wire goes where?'"


Sarrriesfan
Posted: Wednesday, February 19, 2020 4:19:33 PM

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Islami wrote:
Some stars are made of gas only.


Not quite Islami.
Although stars are made of Hydrogen and Helium they are at such an energetic state that they the state of matter known as a plasma rather than gas.
The subatomic particles become disassociated from each other and free electrons float around in the cloud.
Islami
Posted: Wednesday, February 19, 2020 11:54:44 PM
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Ashwin Joshi posted;

At the center of nearly every galaxy lies a monster, a giant black hole millions or even billions of times heavier than the Sun. Some, known as quasars or active galactic nuclei, shine brightly from across the universe as they continuously devour surrounding gas
Sarrriesfan
Posted: Thursday, February 20, 2020 1:11:07 AM

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Location: Luton, England, United Kingdom
Islami wrote:
Ashwin Joshi posted;

At the center of nearly every galaxy lies a monster, a giant black hole millions or even billions of times heavier than the Sun. Some, known as quasars or active galactic nuclei, shine brightly from across the universe as they continuously devour surrounding gas


Interstellar clouds can be gas or plasma, but when in a main sequence star at the temperatures and pressures within Hydrogen and a Helium are plasmas.
That is why in our experiments on Earth to create nuclear fusion as a power source like the a Tokamak chamber magnetic fields are used to hold the plasma a from the sides.


To talk of gases in a star is one of the slight over simplifications that is sometimes used by science writers who are talking to a general audience, but it’s not strictly correct.
In the same way we are often told the Earth 🌏 is round, really it’s not the actual shape it has is an oblate spheroid.
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