Questions that plague physics

Various unsolved physical problems and the theories involved with them are discussed. Three top questions that plague physics include nature of dark energy, reconcile of black hole evaporation with quantum mechanics and existence of extra dimensions. The limitations of string theory and loop quantum gravity in explaining the nature of dark energy in the universe are discussed. Both of the theory stem from one basic idea that there is a mathematical problem with general gravity and that one can not go down to zero in a point particle, which is considered one way to get rid of mathematical infinities.