The length scale on which the quantized nature of gravity should first become evident,
where G is the universal gravitational constant, h is Planck's constant, and c is the speed of light (Shu 1982, p. 397). If h-bar is used instead of plain h, the corresponding length is
Planck Area, Planck Mass, Planck Time
References
Shu, F. H. The Physical Universe: An Introduction to Astronomy. Mill Valley, CA: University Science Books, p. 397, 1982.
