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Author Topic: Black hole spinning at close to the theoretical limit  (Read 385 times)

ta0

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Black hole spinning at close to the theoretical limit
« on: November 15, 2023, 10:38:31 AM »

The supermassive black hole at the center of the Milky Way is spinning at close to the relativistic limit.
Sagittarius A* has a mass of 4.5 million suns and it has a spin parameter between 0.84 and 0.96, being 1 the theoretical maximum.

https://www.livescience.com/space/black-holes/our-galaxys-monster-black-hole-is-spinning-at-top-speed-and-its-dragging-everything-along

If I understand correctly, the spin and precession of a top orbiting the black hole will be affected through the Thirring–Lense effect. This is in addition to the static effect of the high gravity. In particular, the black hole will try to drag the top so it spins in the opposite direction to the black hole.

This is what I call an extreme top!  >:D However, not the largest: the one at the heart of galaxy M87 is spinning at between 0.89 and 0.91, despite having the mass of 6.5 billion suns!  :o
« Last Edit: November 15, 2023, 03:54:20 PM by ta0 »
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Jeremy McCreary

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Re: Black hole spinning at close to the theoretical limit
« Reply #1 on: November 15, 2023, 12:05:20 PM »

If I understand correctly, the spin and precession of a top orbiting the black hole will be affected through the Thirring–Lense effect. This is in addition to the static effect of the high gravity. In particular, the black hole will try to drag the top so it spins in the opposite direction to the black hole.

That's been my experience with the black hole down the street. >:D

I still subscribe to the notion that a true top must be supported at a single point and must fall when not spinning. Which implies both a gravitational center and a support. For our tops, that center is Earth's CM. For Sgr A, the Milky Way's central supermassive black hole, it's the Great Attractor. Now all we need is a volunteer for the support.
« Last Edit: November 15, 2023, 01:14:44 PM by Jeremy McCreary »
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