Starship Asterisk*

APOD Quasars are among the most distant objects we see

Ranzilch wrote: ↑Tue Feb 22, 2022 1:26 pm The word “intervening universe” here is the same meaning of "intervening galaxy" or it's the late period of universe from a timeline perspective?
Anyone please explain me more information about this term "intervening universe", I am a bit confused here, thanks.

Chris Peterson wrote: ↑Tue Feb 22, 2022 3:02 pm

Ranzilch wrote: ↑Tue Feb 22, 2022 1:26 pm
The word “intervening universe” here is the same meaning of "intervening galaxy" or it's the late period of universe from a timeline perspective? Anyone please explain me more information about this term "intervening universe", I am a bit confused here, thanks.

I take it to be a reference to time. Observations that span the very early Universe to the present.

• Clearly, these early quasars are suffering from compulsive and other eating disorders:

https://en.wikipedia.org/wiki/Intervention_(counseling) wrote:
<<An intervention is an orchestrated attempt by one or more [universes] – usually family and friends – to get someone to seek professional help with a substance use disorder or some kind of traumatic event or crisis, or other serious problem. Interventions have been used to address serious personal problems, including alcohol use disorder, compulsive gambling, substance use disorder, compulsive eating and other eating disorders, self harm and being the victim of abuse.>>

• A tutor who tooted the flute,
  Tried to tutor two tooters to toot.
  Said the two to the tutor,
  "Is it tougher to toot
  Or to tutor two tooters to toot?"

https://en.wikipedia.org/wiki/Quasar wrote:A quasar (/ˈkweɪzɑːr/; also known as a quasi-stellar object, abbreviated QSO) is an extremely luminous active galactic nucleus (AGN), powered by a supermassive black hole, with mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc. Gas in the disc falling towards the black hole heats up because of friction and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than a galaxy such as the Milky Way.[2][3] Usually, quasars are categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.[4]

johnnydeep wrote: ↑Tue Feb 22, 2022 10:27 pm From the Wikipedia link to quasar:

https://en.wikipedia.org/wiki/Quasar wrote:A quasar (/ˈkweɪzɑːr/; also known as a quasi-stellar object, abbreviated QSO) is an extremely luminous active galactic nucleus (AGN), powered by a supermassive black hole, with mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc. Gas in the disc falling towards the black hole heats up because of friction and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than a galaxy such as the Milky Way.[2][3] Usually, quasars are categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.[4]

I am always amazed that the quasar's infalling gas and dust can generate so much energy merely due to friction - with no nuclear processes involved - and nevertheless outshine an entire galaxy of furiously fusing stars!

neufer wrote: ↑Tue Feb 22, 2022 4:15 pm

Chris Peterson wrote: ↑Tue Feb 22, 2022 3:02 pm

Ranzilch wrote: ↑Tue Feb 22, 2022 1:26 pm
The word “intervening universe” here is the same meaning of "intervening galaxy" or it's the late period of universe from a timeline perspective? Anyone please explain me more information about this term "intervening universe", I am a bit confused here, thanks.

I take it to be a reference to time. Observations that span the very early Universe to the present.

• Clearly, these early quasars are suffering from compulsive and other eating disorders:

https://en.wikipedia.org/wiki/Intervention_(counseling) wrote:
<<An intervention is an orchestrated attempt by one or more [universes] – usually family and friends – to get someone to seek professional help with a substance use disorder or some kind of traumatic event or crisis, or other serious problem. Interventions have been used to address serious personal problems, including alcohol use disorder, compulsive gambling, substance use disorder, compulsive eating and other eating disorders, self harm and being the victim of abuse.>>

• A tutor who tooted the flute,
  Tried to tutor two tooters to toot.
  Said the two to the tutor,
  "Is it tougher to toot
  Or to tutor two tooters to toot?"

Chris Peterson wrote: ↑Tue Feb 22, 2022 10:54 pm

johnnydeep wrote: ↑Tue Feb 22, 2022 10:27 pm From the Wikipedia link to quasar:

https://en.wikipedia.org/wiki/Quasar wrote:A quasar (/ˈkweɪzɑːr/; also known as a quasi-stellar object, abbreviated QSO) is an extremely luminous active galactic nucleus (AGN), powered by a supermassive black hole, with mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous accretion disc. Gas in the disc falling towards the black hole heats up because of friction and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosities thousands of times greater than a galaxy such as the Milky Way.[2][3] Usually, quasars are categorized as a subclass of the more general category of AGN. The redshifts of quasars are of cosmological origin.[4]

I am always amazed that the quasar's infalling gas and dust can generate so much energy merely due to friction - with no nuclear processes involved - and nevertheless outshine an entire galaxy of furiously fusing stars!

It isn't really friction in the usual sense of the word. It's a fluid dynamic process where atoms collide with each other and transfer momentum in complex ways. The physics is related to ideas like viscosity and moment diffusion. You have a very large volume of gas that is compressed to something more like a liquid than a gas (near the event horizon) moving at relativistic speeds. That's an immense amount of kinetic energy.

alter-ego wrote: ↑Thu Feb 24, 2022 5:10 am For all practical purposes, consider 50% of the mass energy is converted in the accretion disk, compared to about 0.5% in fusion. It's hard to fathom, and kind of ironic that the weak force is the primary channel for the highest emitted powers in the Universe.

johnnydeep wrote: ↑Wed Feb 23, 2022 1:22 pm

Chris Peterson wrote: ↑Tue Feb 22, 2022 10:54 pm

johnnydeep wrote: ↑Tue Feb 22, 2022 10:27 pm From the Wikipedia link to quasar:



I am always amazed that the quasar's infalling gas and dust can generate so much energy merely due to friction - with no nuclear processes involved - and nevertheless outshine an entire galaxy of furiously fusing stars!

It isn't really friction in the usual sense of the word. It's a fluid dynamic process where atoms collide with each other and transfer momentum in complex ways. The physics is related to ideas like viscosity and moment diffusion. You have a very large volume of gas that is compressed to something more like a liquid than a gas (near the event horizon) moving at relativistic speeds. That's an immense amount of kinetic energy.

Interesting. Still seems hard to believe that the energy released can beat fusion. I wonder what percent of the infalling matter's mass gets converted to energy in the accretion disk. Or is that not happening at all and all the energy ultimately coming from the change in gravitational potential energy? (Hmm, I seem to remember being confused about this in prior posts about things falling onto neutron stars...)

Chris Peterson wrote: ↑Thu Feb 24, 2022 3:42 pm

johnnydeep wrote: ↑Wed Feb 23, 2022 1:22 pm
Still seems hard to believe that the energy released can beat fusion. I wonder what percent of the infalling matter's mass gets converted to energy in the accretion disk. Or is that not happening at all and all the energy ultimately coming from the change in gravitational potential energy? (Hmm, I seem to remember being confused about this in prior posts about things falling onto neutron stars...)

What does that mean, "beat fusion"? If all the matter in the accretion disc underwent fusion, it would be vastly more energetic. As it is, something like a third of the mass in the disc is eventually converted to energy, which is a huge amount of energy. In a star, you have only the tiniest amount of material that is undergoing fusion. When hydrogen fuses to helium, the energy conversion is very efficient. But it is also very rare. If all the material in a star fused simultaneously, you would also have an intensity greater than a galaxy. In fact, that's pretty much what happens in a supernova.

• 56 protons of mass 56.4075 Daltons are transformed into one
  iron-56 nuclei of mass 55.935 Daltons for an efficiency of ~ 1%

https://en.wikipedia.org/wiki/Foe_(unit) wrote:
<<A foe is a unit of energy equal to 10⁴⁴ joules or 10⁵¹ ergs, used to express the large amount of energy released by a supernova. This unit of measure is convenient because a supernova typically releases about one foe of observable energy in a very short period (which can be measured in seconds). [Note: a core collapse supernova can release ~100 foe of neutrinos.] In comparison, if the Sun had its current luminosity throughout its entire lifetime, it would release ≈ 1.2 foe. One solar mass has a rest mass energy of 1787 foe.>>

https://en.wikipedia.org/wiki/Quasar wrote:
<<Since quasars exhibit all the properties common to other active galaxies such as Seyfert galaxies, the emission from quasars can be readily compared to those of smaller active galaxies powered by smaller supermassive black holes. To create a luminosity of 10⁴⁰ watts (the typical brightness of a quasar), a supermassive black hole would have to consume the material equivalent of 10 solar masses per year. The brightest known quasars devour 1000 solar masses of material every year. The largest known is estimated to consume matter equivalent to 10 Earths per second. Quasar luminosities can vary considerably over time, depending on their surroundings.

Radiation from quasars is partially "nonthermal" (i.e., not due to black-body radiation), and approximately 10% are observed to also have jets and lobes like those of radio galaxies that also carry significant (but poorly understood) amounts of energy in the form of particles moving at relativistic speeds. Quasars can be detected over the entire observable electromagnetic spectrum, including radio, infrared, visible light, ultraviolet, X-ray and even gamma rays. Most quasars are brightest in their rest-frame ultraviolet wavelength of 121.6 nm Lyman-alpha emission line of hydrogen, but due to the tremendous redshifts of these sources, that peak luminosity has been observed as far to the red as 900.0 nm, in the near infrared. A minority of quasars show strong radio emission, which is generated by jets of matter moving close to the speed of light. When viewed downward, these appear as blazars.>>

neufer wrote: ↑Thu Feb 24, 2022 5:26 pm

Chris Peterson wrote: ↑Thu Feb 24, 2022 3:42 pm

johnnydeep wrote: ↑Wed Feb 23, 2022 1:22 pm
Still seems hard to believe that the energy released can beat fusion. I wonder what percent of the infalling matter's mass gets converted to energy in the accretion disk. Or is that not happening at all and all the energy ultimately coming from the change in gravitational potential energy? (Hmm, I seem to remember being confused about this in prior posts about things falling onto neutron stars...)

What does that mean, "beat fusion"? If all the matter in the accretion disc underwent fusion, it would be vastly more energetic. As it is, something like a third of the mass in the disc is eventually converted to energy, which is a huge amount of energy. In a star, you have only the tiniest amount of material that is undergoing fusion. When hydrogen fuses to helium, the energy conversion is very efficient. But it is also very rare. If all the material in a star fused simultaneously, you would also have an intensity greater than a galaxy. In fact, that's pretty much what happens in a supernova.

Fusion is basically a process by which:

• 56 protons of mass 56.4075 Daltons are transformed into one
  iron-56 nuclei of mass 55.935 Daltons for an efficiency of ~ 1%

This does not come close to efficiency of a quasar :!: