Such a black hole would have formed early in the cluster's history, and the stars would have remained orbiting around its massive gravitational force ever since. Brian Yanny of the Fermi National Accelerator Laboratory says most theorists lean towards core collapse. He explains the problem with the black hole theory lies in cluster formation. Since all of the stars in a globular cluster are the same age, its a mystery how one would have all of a sudden become older than the others. The star would have died and collapsed into a black hole, yet would be surrounded by stars supposedly at the same point in stellar evolution.
Researchers can use computers to create models of the two theories.
It turns out that core collapse has been observed in computer simulations, but modeling a black hole has been more difficult, says Yanny. The drawback to computer modeling is that exact simulations of a cluster core would require faster computers than those that exist today. For now, Yanny says, people creating computer models have to simplify some parts of the equations with regard to the interactions of stars and gas in the earlier stages of cluster evolution.