«How many black holes are there?» «How many black holes are there?» 100 million stellar-mass black holes HubbleSite: "How many black holes are there?" 100 million estimated «How many black holes are there?» HubbleSite: "How many black holes are there?" many more black holes than people algumas suposições educadas HubbleSite: "How many black holes are there?" 100 million na milijone many more black holes than people thousands of black hole births occurring each day many more black holes than people some educated guesses