## Over 40 Quintillion Black Holes Are in the Observable Universe, New Estimate Finds

A team of astrophysicists has calculated the number of starsBlack holes in the observable universe have a mass of 40 quintillion, which is 1% of the total ordinary matter in the universe. The researchers focus on stellar-mass black holes, the smallest known group, but note that their calculations could help address the longstanding mystery of … Read more