A tiny ball weighing a fraction of a milligram, suspended in a magnetic field and cooled to near absolute zero, oscillates for 110 hours without stopping: this is record isolation. The energy loss is so small that the system's entropy barely increases, making any external influence noticeable.
The pendulum already sensed nudges from single atoms of helium-3 in superfluid helium — the force was femtonewtons, less than the weight of a bacterium divided by a billion. Inspired by Schrödinger's paradoxes, physicists hope to test spacetime curvature effects at the quantum level — to see how a macroscopic object behaves like an elementary particle.
Superfluid helium can spontaneously leave an open cup: it simply flows over the edge, ignoring gravity, like a living creature.