APOD: Black Hole Accreting with Jet (2017 Mar 27)

[APOD Robot]

Black Hole Accreting with Jet

Explanation: What happens when a black hole devours a star? Many details remain unknown, but recent observations are providing new clues. In 2014, a powerful explosion was recorded by the ground-based robotic telescopes of the All Sky Automated Survey for SuperNovae (ASAS-SN) project, and followed up by instruments including NASA's Earth-orbiting Swift satellite. Computer modeling of these emissions fit a star being ripped apart by a distant supermassive black hole. The results of such a collision are portrayed in the featured artistic illustration. The black hole itself is a depicted as a tiny black dot in the center. As matter falls toward the hole, it collides with other matter and heats up. Surrounding the black hole is an accretion disk of hot matter that used to be the star, with a jet emanating from the black hole's spin axis.

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[heehaw]

Generally, I don't like fakes (artist's impressions, especially of exoplanets), but this one I think is pretty good!

[Boomer12k]

"In...Through....and BEYOND..." The Black Hole...

:---[===] *

[Fred the Cat]

I was surmising the other day that a black hole could only be if its substance could exist superimposed on itself. Within my amateur knowledge of physics the only bosons seemed to fit that limitation. Since fermions can't occupy the same physical space, they seemed ruled-out of any existence but the "outside" of that concept of a physical black hole.

Is that a terrible "superposition" to take?

[neufer]

I was surmising the other day that a black hole could only be if its substance could exist superimposed on itself. Within my amateur knowledge of physics the only bosons seemed to fit that limitation. Since fermions can't occupy the same physical space, they seemed ruled-out of any existence but the "outside" of that concept of a physical black hole.

Is that a terrible "superposition" to take?

<<The idea that there should be an absolute upper limit for the mass of a cold (as distinct from thermal pressure supported) self-gravitating body dates back to the work of Lev Landau, in 1932, whose reasoning was based on the Pauli exclusion principle according to which the Fermionic particles in sufficiently compressed matter would be forced into energy states so high that their rest mass contribution would become negligible compared with the relativistic kinetic contribution determined just by the relevant quantum wavelength λ which would be of the order of the mean interparticle separation.>>

<<[Neutron stars] are supported against collapse by neutron degeneracy pressure, a phenomenon described by the Pauli exclusion principle. If the remnant has too great a density, something which occurs in excess of an upper limit of the size of neutron stars at 2–3 solar masses, it will continue collapsing to form a black hole.

Neutrons in a degenerate neutron gas are spaced much more closely than electrons in an electron-degenerate gas because the more massive neutron has a much shorter wavelength at a given energy. Typical separations are comparable with the size of the neutron and the range of the strong nuclear force and it is actually the repulsive nature of the latter at small separations that primarily supports neutron stars more massive than 0.7 solar masses (which includes all measured neutron stars).

There is an upper limit to the mass of a neutron-degenerate object, the Tolman–Oppenheimer–Volkoff limit, which is analogous to the Chandrasekhar limit for electron-degenerate objects. The limit for objects supported by ideal neutron degeneracy pressure is only 0.75 solar masses. For more realistic models including baryon interaction, the precise limit is unknown, as it depends on the equations of state of nuclear matter, for which a highly accurate model is not yet available. Above this limit, a neutron star may collapse into a black hole, or into other, denser forms of degenerate matter (such as quark matter) if these forms exist and have suitable properties (mainly related to degree of compressibility, or "stiffness", described by the equations of state).>>

[Fred the Cat]

Thank "higher levels of existence" for professionals that add even more concepts difficult to comprehend. I appreciate you Art!

[Chris Peterson]

I was surmising the other day that a black hole could only be if its substance could exist superimposed on itself. Within my amateur knowledge of physics the only bosons seemed to fit that limitation. Since fermions can't occupy the same physical space, they seemed ruled-out of any existence but the "outside" of that concept of a physical black hole.

You assume that there's an actual singularity in the center of a black hole. That could easily be a false assumption. And you assume that what exists outside of a black hole as a boson or fermion remains that at or near the center of a black hole.

Bottom line: nobody has any reasonable understanding of what's going on at the center of a black hole. Fortunately, that lack of knowledge isn't important when it comes to understanding most of the properties of a black hole.

[Fred the Cat]

I equally appreciate your thoughts Chris but I can't keep my curiosity from roaming into the spaces where fermions and bosons coexist and wondering about what is not yet understood.

[Chris Peterson]

I equally appreciate your thoughts Chris but I can't keep my curiosity from roaming into the spaces where fermions and bosons coexist and wondering about what is not yet understood. 8-)

Nothing wrong with curiosity or with wondering. It's just important not to lose touch with that "not yet understood" component.

[Fred the Cat]

I equally appreciate your thoughts Chris but I can't keep my curiosity from roaming into the spaces where fermions and bosons coexist and wondering about what is not yet understood.

Nothing wrong with curiosity or with wondering. It's just important not to lose touch with that "not yet understood" component.

I agree.

Knock, knock
"Who's there?"
"Where?"
"What's where?"
"When?"
"Why now?"
It's just "how!"

With attempts at humor during the process.

[neufer]

Thank "higher levels of existence" for professionals that add even more concepts difficult to comprehend.

Fermions can't get closer than a half wavelength apart.

But there is no limit to how small those wavelengths can get in a deep gravitational well.

[gva]

I am confused by the depiction. I have always assumed that an accretion disk is shaped like...a disk. In this depiction, the black hole appears to be in a deep well; i.e., the accretion disk appears to be shaped more like an accretion "cloud".

I am surprised because I always thought that accreting matter orbits around the black hole quite a few times before reaching the event horizon. With every orbit, matter that orbits at an angle, relative to the average disk, experiences a lot of collisions and quickly settles into an orbit in the plane of the disk. This is the mechanism that makes Saturn's ring so extremely thin and almost perfectly circular. I did not expect the accretion disk around a black hole to be as thick as depicted. I was expecting something more similar to Saturn's rings.

[bystander]

http://asterisk.apod.com/viewtopic.php?t=36964

[geckzilla]

I am confused by the depiction. I have always assumed that an accretion disk is shaped like...a disk. In this depiction, the black hole appears to be in a deep well; i.e., the accretion disk appears to be shaped more like an accretion "cloud".

I am surprised because I always thought that accreting matter orbits around the black hole quite a few times before reaching the event horizon. With every orbit, matter that orbits at an angle, relative to the average disk, experiences a lot of collisions and quickly settles into an orbit in the plane of the disk. This is the mechanism that makes Saturn's ring so extremely thin and almost perfectly circular. I did not expect the accretion disk around a black hole to be as thick as depicted. I was expecting something more similar to Saturn's rings.

They can vary in size, density, and flared thickness depending on whether material is actively being added, how long it's been accreting, where the material is coming from, what kind of spin the black hole has, and whether or not the disk is aligned with the black hole's spin axis... that said, I'm sure the illustration still only vaguely resembles reality. Nothing can change the fact that we've never actually seen a black hole accretion disk right now, and artists, for all of their creativity, work best when they can see what they're depicting.

[BDanielMayfield]

I am confused by the depiction. I have always assumed that an accretion disk is shaped like...a disk. In this depiction, the black hole appears to be in a deep well; i.e., the accretion disk appears to be shaped more like an accretion "cloud".

I am surprised because I always thought that accreting matter orbits around the black hole quite a few times before reaching the event horizon. With every orbit, matter that orbits at an angle, relative to the average disk, experiences a lot of collisions and quickly settles into an orbit in the plane of the disk. This is the mechanism that makes Saturn's ring so extremely thin and almost perfectly circular. I did not expect the accretion disk around a black hole to be as thick as depicted. I was expecting something more similar to Saturn's rings.

A black hole is in a well, sort of; a 3 dimensional gravity well. No one's ever seen one up this close. They twist spacetime too. So, hard to rap our imaginations around to come up with something realistic looking.

Bruce

[Chris Peterson]

A black hole is in a well, sort of; a 3 dimensional gravity well. No one's ever seen one up this close. They twist spacetime too. So, hard to rap our imaginations around to come up with something realistic looking.

As a gravity well, a black hole isn't substantially different from a planet or a star. You actually have to get inside its event horizon before things get really odd. We don't see the black hole in this image because it's too small. We just see the effect it has on ordinary matter around it, which is pretty much the same as if the black hole was replaced by a neutron star or any other compact mass. The only difference in this case is scale- a supermassive black hole can command a larger accretion disk. But that disk itself, the jet, pretty much everything in this image are just manifestations of ordinary physics, much of which we understand pretty well. It shouldn't strain our imaginations all that much.

(Black holes, like all bodies with mass, are 4-dimensional gravity wells.)

[LirrelJohn]

Generally, I don't like fakes (artist's impressions, especially of exoplanets), but this one I think is pretty good!

In general, I'm with you, especially with singularities and their accretion disks though "artists' impressions" of planets and planetary systems also irk me a little. I would prefer we just send probes to find out what they look like.
This one I find yucky and inaccurate, also trite and clichéic. It even has the downwards flowing drain of every other accretion disk ever painted which I find ugly.
The colouring I find exceptionally fantastic and incredible. Accretion disks are hot and bright, not smoky and misty.
This image is poor astronomy and even poorer poetry.

Not that I could do better, I never could draw.

[DavidLeodis]

Black holes are fascinating .

In the Swift overview information that can be found through the Swift link in the credit it states "By the end of this day, somewhere in the visible universe a new black hole will have formed. Gamma-ray bursts (GRBs), the most distant and powerful explosions known, are likely the birth cries of these new black holes". With the vastness of the Universe I probably should not be surprised at that seemingly high rate of Black Hole formation but it still amazes me.

As I understand it no light can get out of a Black Hole so I wonder If there is a White Hole balancing opposite where light is being released? Sorry for the vagueness (and likely naivety) of my query as I'm unsure how to actually ask it.

[Silly Boy]

Black holes are fascinating .

In the Swift overview information that can be found through the Swift link in the credit it states "By the end of this day, somewhere in the visible universe a new black hole will have formed. Gamma-ray bursts (GRBs), the most distant and powerful explosions known, are likely the birth cries of these new black holes". With the vastness of the Universe I probably should not be surprised at that seemingly high rate of Black Hole formation but it still amazes me.

As I understand it no light can get out of a Black Hole so I wonder If there is a White Hole balancing opposite where light is being released? Sorry for the vagueness (and likely naivety) of my query as I'm unsure how to actually ask it.

I don't know but it seems an anti-singularity with massive anti-gravity is what you're contemplating on. If such a thing were possible then it seems to me that it would be just as invisible as a black hole simply by being unable to generate light via fusion and by pushing all light/matter away from itself?

[DavidLeodis]

Thanks Silly Boy for your help .

In my simple very non-scientific mind I assume that there is an opposite to everything to balance things out, which is why I wondered about 'White Holes'. If there are no opposites to Black Holes then I guess that over the billions of years left of the Universe then Black Holes will gradually merge and finally there will be just one left and that will be the end of things (before it all starts again ). Perhaps Black and White Holes are a grey area so to speak.

[Chris Peterson]

Thanks Silly Boy for your help :).

In my simple very non-scientific mind I assume that there is an opposite to everything to balance things out, which is why I wondered about 'White Holes'. If there are no opposites to Black Holes then I guess that over the billions of years left of the Universe then Black Holes will gradually merge and finally there will be just one left and that will be the end of things (before it all starts again :wink: ). Perhaps Black and White Holes are a grey area so to speak.

Most black holes will never merge. For the most parts, the only black hole mergers will be the central black holes of galaxies within individual clusters. There's no mechanism for others to merge, especially as most are already moving away from each other. Eventually, all the black holes will evaporate and cease to exist.

[DavidLeodis]

Thanks Silly Boy for your help .

In my simple very non-scientific mind I assume that there is an opposite to everything to balance things out, which is why I wondered about 'White Holes'. If there are no opposites to Black Holes then I guess that over the billions of years left of the Universe then Black Holes will gradually merge and finally there will be just one left and that will be the end of things (before it all starts again ). Perhaps Black and White Holes are a grey area so to speak.

Most black holes will never merge. For the most parts, the only black hole mergers will be the central black holes of galaxies within individual clusters. There's no mechanism for others to merge, especially as most are already moving away from each other. Eventually, all the black holes will evaporate and cease to exist.

Thanks for your help Chris .

That is very interesting information that you have given.

[Fred the Cat]

An analogy between a glory hole and a black hole may not be very good but when you get very close to one there is definitely a pucker factor that I would not want ramped up to galactic dimensions.

Their sounds are eerie too. I do think the spin factor will gain momentum as science creeps closer.