If the universe oscillates between a Big Bang and a Big crunch, can two small volumes of dark energy, at opposite ends of it, be considered to be undergoing simple harmonic oscillation? The potential energy of an oscillator could be given by G m1 m2 /r where m1 is the mass of a volume of dark energy, the mass of the universe is10^52 kg,r = 10^26 metres - the current size of the universe . Since the PE of a simple harmonic oscillator is given by PE = 1/2 k x^2, the force constant k becomes 10 ^ -37 m2 assuming r is also about equal to the maximum extension of the oscillator. using frequency of oscillator = ( k / m2 ) ^1/2, frequency = ( 10^ -37m2 / m2 )^ 1/2 = 10^ - 18.5 per second. In other words the universe could oscillate every 10 ^ 18.5 seconds - about its current age!! Quantizing this oscillator gives its potential energy changing in units of 10^-52 Joules.Could this be the energy of gravitons turning into dark energy as the universe expands and the potential energy of the oscillator increases?