M87* One Year Later: Catching the Black Hole's Turbulent Accretion Flow(eventhorizontelescope.org)

M87* One Year Later: Catching the Black Hole's Turbulent Accretion Flow

https://eventhorizontelescope.org/m87-one-year-later-catching-black-holes-turbulent-accretion-flow

3 comments

fch42geçen yıl

It's rather fascinating to find that in the case of M87*, the black hole and its accretion disk are counterrotating. A rotating black hole has a giant amount of angular momentum, and that has "accreted" onto it during its formation and lifetime; even if born from many mergers, and gone through billions of years of accretion, the current angular momentum / spin of M87* says that overall, what came together to form it all rotated largely in the same direction. The fact that M87*'s jet is straight also means the black hole can't have wobbled much in its (more recent) history.

So why did the accretion flip ? How often does this happen ? How big is the influence of accretion (say, at high rates / eddington limit) on the black hole's angular momentum over time ? How long can such a counterrotating condition persist ? How common are cases where, say, the jet direction of a active black hole changed massively (or even reversed), indicating a "major flip" event for the black hole's spin ?

(many questions just curious)

versteegengeçen yıl

What I think is the most interesting part:

> “When gas spirals into a black hole from afar, it can either flow in the same direction the black hole is rotating, or in the opposite direction. We found that the latter case is more likely to match the multi-year observations thanks to their relatively higher turbulent variability”

The direction the black hole is rotating makes a difference due to frame dragging.

https://en.wikipedia.org/wiki/Frame-dragging

metalmangeçen yıl

Yup!, that is interesting, makes you think! So why does the acretion disk form at all? as a singularity should have be perfectly uniform gravitationaly. So the laws change @ the boundry and what we percieve as spin in a black hole, may be an effect caused by the integration of a singularitys gravity with 3 dimensional space. Under the event horison is the naked singularity, where something else, entirely, is happening. But yes, the lack of handedness to the disk points to something not quite playing by the rules. And that there is evidence of some turbulence, shear?, at the event horison, speaks to some possible "leakage" from the black hole, or it could just be a natural phenominon of a singularity and 3D space existing at the same time and place. And the link to frame dragging, desribes, what is called shear in fluids, which takes us all the way back to is light a fluid, particle,wave,field, or what arguments, good fun.