A Black-Hole Bonanza

摘要

They're the galaxy's equivalent of the graveyard In the attic- except on a much bigger scale. Astronomers have discovered two of the largest black holes ever recorded, which together are 10 times the size of our solar system. To estimate the black holes' size, scientists used earthbound and celestial telescopes to record the speeds of stars caught in the holes' gravitational pull. The sprawling stellar burial grounds contain billions of stars, some of which weigh as much as 21 billion suns. And since the holes are located at the center of galaxies, they could provide hints about how galaxies are formed from the swirling gases emitted by the stars.