That's right. On a wider scale, the concept of entropy describes a dissipation of energy within the universe as a whole. Without our intervention, stars, worlds, and galaxies will expand too far apart. On a long enough timeline, the universe will eventually suffer heat death. Nothing would survive.
[Tilting his head, adding in that same unendingly cheerful tone.] The lives of a few human girls is a worthy price to pay in order to save the future, don't you think?