Assertion: quasar | /r/HasProperty | formed
Facets:
Source sentences:
text: Most quasars were formed approximately 12 billion years ago, and they are normally caused by collisions of galaxies, with the galaxies' central black holes merging to form either a supermassive black hole or a binary black hole system.
text: Most quasars were formed approximately 12 billion years ago, and they are normally caused by collisions of galaxies, with the galaxies' central black holes merging to form either a supermassive black hole or a binary black hole system.
text: A quasar is formed when a super massive black hole at the centre of a galaxy has enough material All nearby galaxies are too old to be quasars unless they collide.