Assertion: dinosaur's extinction | /r/HasProperty | due
Facets:
value: to a single catastrophic event
type: CAUSE
Source sentences:
text: In 1956, Russian astronomer Joseph Shklovsky (1916-85) became the first scientist to consider the extinction was due to a single catastrophic event when he theorized that a supernova (the explosion of a dying star) showered the earth in radiation that could have killed the dinosaurs.