A new study has investigated stellar mass black holes, which are black holes with masses between a few to some hundred solar masses, that originated at the end of the life of massive stars. According to the study, a remarkable amount of around 1 percent of the overall ordinary matter of the universe is locked up in stellar mass black holes. Astonishingly, the researchers have found that the number of black holes within the observable universe at present time is about about 40 times 10 to the exponent 18.