Assertion: astronomer | /r/CapableOf | observe snapshots of different systems
Facets:
value: at unique points
type: LOCATION
value: in their evolution
type: TEMPORAL
Source sentences:
text: Because it takes millions to billions of years for a system of stars or a galaxy to complete a life cycle, astronomers must observe snapshots of different systems at unique points in their evolution to determine how they form, evolve, and die.