Assertion: aurora borealis | /r/AtLocation | polar zone
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Aurora Borealis is a bright glow observed in the night sky, usually in the polar zone.
text: Aurora Borealis is a bright glow observed in the night sky, usually in the polar zone.
text: northern Lights or aurora borealis are natural different colored light displays, which are usually observed in the night sky, particularly in the polar zone.