Gravitational Lens

Out of so many properties of gravitation, gravitational lens is more important. It contains all aspects of gravitation. It has the power of prediction of gravitation of newly born stars, also predicts about the life of stars including the duration of being dwarf star or black hole. As gravitational pull of a star determines the size, strength and life, so, gravitational lens can view all dimension in its formation. The quadrupole moment (or the l-th time derivative of the l-th multipole moment) of an isolated system's stress-energy tensor must be nonzero in order for it to emit gravitational radiation. This is analogous to the changing dipole moment of charge or current necessary for electromagnetic radiation. Key words- Gravitational lens, stress energy tensor, multipole moment, quadrupole, prediction, etc