By Ron Cowen
The most massive stars in the universe collapse to form black holes at the end of their lives. Theory suggests that such black holes can’t have much more than about 10 times the sun’s mass, but a team has now identified one that tips the scales at 15.65 times the sun’s mass. Another research group has tentative evidence of an even bigger beast.
The findings may call into question current predictions about the evolution and ultimate fate of heavyweight stars.