Assertion: whirlpool | /r/HasAspect | spiral structure
Facets:
Source sentences:
text: In 1845, William Parsons, 3rd Earl of Rosse, employing a 72-inch (1.8 m) reflecting telescope at Birr Castle, Ireland, found that the Whirlpool possessed a spiral structure, the first "nebula" to be known to have one.