Nearly 400,000 kilometres away, the moon performs a quiet and ancient service — steadying the tilt of our world, pulling the tides, slowing our spin, and lighting the night for creatures that have evolved around its rhythms for billions of years. NASA scientists remind us that what we take for scenery is in fact a pillar of planetary stability. To imagine its sudden absence is to glimpse how contingent life on Earth truly is — not a triumph of robustness, but a long negotiation with a very particular set of conditions.