how can black holes spin at almost the speed of light?

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Posts in total: 10

this article says they have found ways to measure how fast black holes spin. 

some of them spin at 99% the speed of light. but physics says for an object to go the speed of light, it has to have infinite mass. so how can these obviously not even close to infinite mass clusters spin at almost the speed of light? does that last percent really matter that much? 
--> @linate
Yes, the last percentage matters. In fact, the last fraction of a percent matters hugely.

You can find the equation that relates mass to speed here: https://www.physlink.com/education/askexperts/ae388.cfm.  

We can use the equation to easily determine the mass multiplier for traveling at various percentages of the speed of light by setting an object's rest mass to 1. Here are a few numbers..

Percentage of C     Mass Mutiplier
25                        1.03
50                        1.15
75                        1.51 
90                        2.29
95                        3.20
99                        7.09
99.5                    10.01
99.9                    22.37
99.99                  70.71
99.999               223.61              
99.9999             707.11
99.99999          2236.07  

At 99 percent of the speed of light, our mass has increased by just over 7 times. But it still heads to infinite as we get incrementally close to C. 
--> @Stronn
excellent post

thanks for the info
--> @linate
There are no black holes. That is mythology.
--> @janesix
There are no black holes. That is mythology.
You need to educate youself. It is clear there is powerful something at all of the galaxeys that a team of scientist studied and the powerful something fits the bill for being a black hole were nothing else does.

This conclusion I read about a few years back.  I think you need to do some research and arrive at a more rational, logical common sense conclusion based on what is observed.

I dunno what new info has come about since I read that. Probably only more info leading to same conclusion.

--> @mustardness
There is no proof of black holes. It is a complete fabrication, like dark matter and dark energy.
--> @janesix
Oh awesome, you’ll be happy to provide your alternative explanations for the x ray output Vs size of Cygnus-x, and provide a new theory that supersedes relativity that explains the orbital dynamics around Sagittarius B?
--> @janesix
There is no proof of black holes. It is a complete fabrication, like dark matter and dark energy.
Obviously you do not believe what I told you and refuse to find that data to better inform yourself of what much learned scientists believe, based on the facts.

You have no facts. You have no observations. You not much of anything except an empty oppinnion.

Who else do we know with these same aspects?

--> @janesix, @Ramshutu
You will also need to explain what happens when the density of a star becomes so great that not even the nuclear strong force is enough to stave off gravitational collapse. What prevents the star from collapsing to a black hole?