Deep inside a black hole? (Image: Serge Brunier/Clemson/NASA)

WE COULD be living inside a black hole. This head-spinning idea is one cosmologist’s conclusion based on a modification of Einstein’s equations of general relativity that changes our picture of what happens at the core of a black hole.

In an analysis of the motion of particles entering a black hole, published in March, Nikodem Poplawski of Indiana University in Bloomington showed that inside each black hole there could exist another universe (Physics Letters B, DOI: 10.1016/j.physletb.2010.03.029). “Maybe the huge black holes at the centre of the Milky Way and other galaxies are bridges to different …