[LibWhacker]

But in the case of the ball on a rope, the "lost" energy goes into stirring up air molecules, etc. Where would the "lost" energy of an oscillating universe go?

[MacDorcha]

what is the universe expanding into?

[Sentis]

LinWacker wrote"But in the case of the ball on a rope, the "lost" energy goes into stirring up air molecules, etc. Where would the "lost" energy of an oscillating universe go?"

It doesnt have anywhere to go it could possibly be the energy that allows the universe to expand. When that initial occillation stops (Energy/matter becomes trapped in black holes, neutron stars etc) the universe would begin to collapse back to a state of singularity.