<http://www.w3.org/1999/02/22-rdf-syntax-ns#first>
<http://pop.h-cdn.co/assets/cm/15/05/768x516/54cb66b0d276d_-_solar_sail_01_0211-xl.jpg>
<http://www.popularmechanics.com/space/g1775/solar-sails-fly-from-science-fiction-into-reality/>