I'm a bit confused about quasars and neutron stars but is it the case that quasars are much much denser than our star and spin many times per second? I think the sun completes one rotation in about 25 days and it's spinning at about 4467mph. I'm pretty sure that density will effect the speed that something can spin? So if a quasar has a mass a million times that of the sun, but it's only the size of new york, how can we work out of it's spinning faster in terms of it's size? Obviously it is smaller but because it is denser would it be spinning faster? I guess what I'm trying to ask is how fast to quasars spin and is there a limit as to how fast they can spin? If they spin too fast would gravity just rip them apart?