1 00:00:00,300 --> 00:00:04,200 HUBBLE FINDS EVIDENCE OF MID-SIZED BLACK HOLE 2 00:00:04,200 --> 00:00:14,780 Astronomers have found the best evidence yet of a black hole of an elusive class known as “intermediate mass.” 3 00:00:14,780 --> 00:00:27,180 This mid-sized black hole betrayed its existence by tearing apart a wayward star that passed too close. 4 00:00:27,180 --> 00:00:43,240 About 50,000 times more massive than our Sun, this black hole is smaller than supermassive black holes that lie at the cores of large galaxies… 5 00:00:43,240 --> 00:00:55,240 …but it’s larger than stellar-mass black holes formed by the collapse of a massive star. 6 00:00:55,240 --> 00:01:08,280 In 2006, satellites detected a powerful flare of X-rays, but researchers weren’t sure if the source was inside or outside our galaxy. 7 00:01:08,280 --> 00:01:21,500 Hubble was pointed at the X-ray source to figure out its precise location. 8 00:01:21,500 --> 00:01:35,000 Hubble found that the X-rays emanated from a distant, dense star cluster on the outskirts of another galaxy… 9 00:01:35,000 --> 00:01:49,820 …the exact place astronomers would expect to find a mid-sized black hole. 10 00:01:49,820 --> 00:02:02,840 Mid-sized black holes are a long-sought “missing link” in black hole evolution. 11 00:02:02,840 --> 00:02:15,040 They’re very difficult to find because they’re smaller and less active than supermassive black holes. 12 00:02:15,040 --> 00:02:35,040 Astronomers essentially have to catch one red-handed in the act of gobbling up a star. And this time, they did. 13 00:02:35,040 --> 00:02:45,000 [ INTENSE MUSIC ]