Kelvin Mason: A dirty black hole (Heinz Leitner)

http://www.redpepper.org.uk/a-dirty-black-hole/?utm_source=Pepperista&utm_campaign=a061213939-96035f6d2dc1a0ab8d89ff1b8516f23b&utm_medium=email&utm_term=0_2d5c5bf744-a061213939-14356333