I'm a physics teacher, and we just did Universal Gravitation last week. I whimsically explained it as "the longing of everything for everything". (They liked it, but devolved into a giggle fest about being attracted to each other.)

Other easily romantic notions in physics:

* we are all born of star stuff

* every breath we take has elements of the same breath as every human who ever lived (excluding some currently living ones, due to diffusion rates, but eventually...)

* (The current grav force between my partner and me is 1.9159965e-15 N)