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/sci/ - Science & Math

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10540565 No.10540565 [Reply] [Original]

Why is it the accretion disc and not the accretion sphere?

I mean, if singularity's pull is equal from all sides, and the event horizon has no equator, what causes the trapped matter to fall into the black hole along a circular path?

>> No.10540570

Angular spin

>> No.10540579

>>10540570
Please explain.

English isn't my fist language, so I may not even know that I know what it is.

>> No.10540583

>>10540565
For the same reason the planets on the solar system are in the same plane.
Matter spins, so at some point this sphere of matter flattens like a piece of dough and you get this flat pancake of matter

>> No.10540585

>>10540579
Google fucking black holes, nigga. I ain't spoon-feeding you

>> No.10540593

>>10540579
Here is an easy explanation, it's the same principle
https://youtu.be/G_Mf7pipKu0

>> No.10540596

>>10540565
For the same reason that when stars form, the leftover gas and dust form a protoplanetary disc around the star.

When material falls in, it starts with some small angular momentum. As it falls closer and closer, it spins up faster like a spinning ice skater pulling their arms in. Eventually, as the gas molecules interact with each other, an orbiting disc is formed.

>> No.10540604

>>10540583
Thank you. A simple, yet informative explanation.
>>10540585
Then don't, Sharrif. Just go on a different thread.

>> No.10540607

>why are rings of saturn rings

>> No.10540617

>>10540593
>>10540596
Thank you two as well.

>> No.10540629

>>10540607
Saturn has an equator. And Saturn

AFAICR, singularities don't.

>> No.10540636

>>10540604
Go on a different site, brainlet.

>> No.10540638

>>10540629
>and Saturn rotates.

>> No.10540650

>>10540636
Yeah, no.

>> No.10540744

>>10540593
I'm not a big fan of that explanation because it doesn't really talk about it from a physics standpoint.

A sphere of matter wouldn't be stable as matter on one orbit would collide with matter from crossing orbits. The collision of this material preserves angular momentum, but not kinetic energy as particles can rub and stick together and radiate energy, reducing their kinetic energy. As kinetic energy is reduced, the material falls into lower and lower orbits while still maintaining the group angular momentum. The combination of the reduced kinetic energy and conservation of angular momentum brings about the formation of a small disk, as you can't have matter with a now reduced kinetic energy from their initial state preserve the group angular momentum without the matter forming a disk.

>> No.10540784

>>10540596
Also once you've got a disk starting to form it has its own gravitational pull that squishes it flatter as well.

>> No.10540798
File: 64 KB, 960x916, angular momentum.gif [View same] [iqdb] [saucenao] [google]
10540798

>>10540570
Makes sense to me. And I'm a massive black brainlet.

>> No.10540851

>>10540593
God! Her voices is so annoying. Everything else in her video rocked tho.

>> No.10540877

>>10540629
Singularities rotate just like Saturn does

>> No.10540945

>>10540877
Isn't it that there are both rotating and non-rotating black holes.

>> No.10540952

>>10540945
That's the theory

>> No.10540954

>>10540952
So what would happen with the theoretical static BH?

Would it even have a disc?

>> No.10540961

>>10540954
It would. Gravity still exists. Matter still wants to fall into it

>> No.10540968

>>10540961
But what would then serve to tip the favour to those specific vectors that form the disc?

>> No.10540973

>>10540968
Angular momentum

>> No.10540975

>>10540954
As the matter that condensed to form the black hole would have angular momentum, a static BH is more of a mathematical idea than a physically possible event. Also static with respect to what? What does that even mean? Furthermore, additional matter falling into the blackhole would have angular momentum and extremely high kenetic energy so would produce a spin very easily.

>> No.10540978

We've come full circle.

>> No.10540984

>>10540973
>>10540975
Right. Forgot about angular momentum.

>> No.10541000

>>10540565
Spinular Ang

>> No.10541008

>>10541000
>spinnular

Is that even a word?

Also, nice trips.

>> No.10541021

>>10540565
>and the event horizon has no equator
that's where you're wrong famlam

>> No.10541037

>>10540798
precession more specifically

>> No.10541141

>>10540565
The same reason why Saturn has a ring of dust and rocks

>> No.10541146

>>10540851
Wait that’s not a man???

>> No.10542721
File: 229 KB, 736x954, WalterRussellVortexMassGeneration.jpg [View same] [iqdb] [saucenao] [google]
10542721

>>10540565
>>10540579
Mix you cheerios really fast and watch them fly out the bowl. Then when all the cheerios fly out continue to mix. The only place you'll be able to "reintegrate cheerios is from the top where there is no angular momentum. This is why a black hole is not a "sphere". The shit has to come in from somewhere.

>>10540583
this anon is a good example too.

>>10540585

>reify an absence
Retarded