About: http://webisa.webdatacommons.org/229236571

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	@MarkMitchison Thanks for that Wikipedia link - so the field is everywhere and light is a wave in which the field is the medium.
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com