Assertion: black hole's mass | /r/HasProperty | packed into region
Facets:
Source sentences:
text: But in other types of radiation—radio waves, infrared, X-rays—astronomers have detected the presence of an object with the mass of four million suns packed into a region smaller than our solar system: a supermassive black hole.
text: The black hole's six-and-a-half billion solar masses are crammed into a region about the size of a solar system.