Submitted by Marianne on June 12, 2015. When physicists talk about Einstein's equation they don't usually mean the famous E=mc2, but another formula, which encapsulates the celebrated general theory of relativity. Einstein published that theory a hundred years ago, in 1915. To celebrate its centenary we asked physicist David Tong of the University of Cambridge to explain what general relativity is and how Einstein's equation expresses it. You can watch his explanation in the video below, or read on.
The goblin shark (Mitsukurina owstoni) is a rare species of deep-sea shark. Sometimes called a  living fossil , it is the only extant representative of the family Mitsukurinidae, a lineage some 125 million years old.This pink-skinned animal has a distinctive profile with an elongated, flattened snout, and highly protrusible jaws containing prominent nail-like teeth.t is usually between 3 and 4 m (10 and 13 ft) long when mature, though it can grow considerably larger. Goblin sharks inhabit upper continental slopes, submarine canyons, and seamounts throughout the world at depths greater than 100 m (330 ft), with adults found deeper than juveniles.
There is a lack of information about the reproduction habits of the goblin shark since the sightings have been few and therefore, also the research. The few data available came from individuals caught accidentally and not from observations directly in their habitat.