In the high atmosphere, a bunch of floating bacteria have figured out physics-- kinetic energy, electromagnetism, momentum, electric potential, etc --but they h

In the high atmosphere, a bunch of floating bacteria have figured out physics-- kinetic energy, electromagnetism, momentum, electric potential, etc --but they have no notion of gravity, being high up and feeling the turbulent forces of air with a much greater strength than the pull downward. Eventually, their astrophysicists say "Look, the cosmos behaves very similarly to how our models predict, except there seems to be an extra force or energy that pulls everything in one direction. If we just add one term to every potential energy equation we have, it all makes sense, but we have no idea where that energy actually comes from."