Rotating black holes? answer: A rotating black hole, also known as a Kerr black hole, is a black hole that possesses angular momentum (spin) resulting from the collapse of a spinning massive star.

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Rotating black hole

Wikipedia

https://en.wikipedia.org › wiki › Rotating_black_hole

As all known stars rotate and realistic collisions have non-zero angular momentum, it is expected that all black holes in nature are rotating black holes.

Types of black holes

Formation

Conversion to a Schwarzschild...

AI Overview

A rotating black hole, also known as a Kerr black hole, is a black hole that possesses angular momentum (spin) resulting from the collapse of a spinning massive star. 

Key Characteristics

The Kerr Metric: Described mathematically by Roy Kerr in 1963, these black holes are defined by their mass and angular momentum rather than just mass alone (like non-rotating Schwarzschild black holes). 
Frame Dragging: The spin of the black hole physically twists and drags the fabric of space and time (spacetime) around it, forcing nearby objects and light to co-rotate in the direction of the spin. 
The Ergosphere: An ellipsoidal region forms just outside the outer event horizon where frame dragging is so extreme that nothing can remain stationary
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Energy Extraction: Advanced theoretical processes, like the Penrose process, allow energy to be extracted directly from the rotational energy of the ergosphere. 
Ring Singularity: Unlike non-rotating black holes that theoretically feature a point-like singularity, rotating black holes possess a ring-shaped singularity inside dual event horizons. 

Most users on Quora agree that because all precursor stars rotate, nearly all astrophysical black holes in nature are rotating. 

If you'd like, I can explain:

• How scientists measure the spin of a black hole
• The mechanics of the Penrose process
• The difference between the inner and outer event horizons

Let me know which area you want to explore!