<http://schema.org/about>
"Physicists have calculated that time is likely to end within the next 4 billion years due to a catastrophe that no one alive at the time will witness."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/earth-matters/space/stories/time-will-end-within-a-few-billion-years-say-physicists>