What is black hole?

• Possible end phase of a star: A star is a massive, luminous ball of plasma having continuous nuclear burning

• Star exhausts nuclear fuel →

• White Dwarf, Neutron Star, Black Hole

• Black hole’s gravitational field is so powerful that even electromagnetic radiation (e.g. visible light) cannot escape

• its pull

• Black Hole is a source of energy in Universe: T~107-10 K

• unlike star when T~106 K