<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/06/480x360/54cfd020d8558_-_solar-system-03-0112-lgn.jpg>
<http://www.popularmechanics.com/space/deep-space/g744/5-weird-planetary-systems/>