<http://schema.org/alternativeHeadline>
"Scientists estimate that rogue worlds outnumber 'normal' worlds with host stars by at least 50 percent in the Milky Way."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/space/stories/orphan-alien-planet-spotted-100-light-years-away>