Dear all, In one of his lectures,Prof. Susskind mentioned that the event horizon "bulges" forward to meet any incoming radiation or matter; and it is a property of Einstein field equations. I have not come across any such property, and if it exists, shouldn't it belong to the Schwarzchild(or Kerr,etc) metric rather? Can someone mathematically explain that property in detail? I want to know the mathematical description of this property. Thanks in advance!