Physics at Planck length

Quantum gravitational effects alter the nature of spacetime at length scales of the order of Planck length (∼ 10 -33 cm). These effects can be investigated by concentratmg one's attention on the conformal degree of freedom of the metric. It can be shown that physically measurable proper interval between any two events, in any. spacetime, IS bounded from below by Planck length. Quantum gravity shows promise In providing a universal ultraviolet cut-off.