<http://schema.org/alternativeHeadline>
"The 'interstellar material' is the leftovers of older stars that have ended their lives in a supernova."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/space/stories/nasa-spacecraft-detects-alien-matter-from-beyond-our-solar-system>