About: http://webisa.webdatacommons.org/126191844

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	With the planets so far discovered, the one datum almost always found, other than their mere existence, is their orbital period -- and even when the exact period is not yet known, it can be estimated.
http://www.w3.org/ns/prov#wasQuotedFrom	unmannedspaceflight.com