Tidal friction is slowing Earth's spin, yet the angular momentum of the Earth and Moon together cannot change. What follows for the Moon?

1. Water rubbing over Earth's face steals spin from the planet. 2. Earth's day is lengthening by about 0.002 second each century as a result. 3. The angular momentum of the whole Earth and Moon system cannot change. 4. So the spin the planet loses has to be handed to the Moon's orbital motion. 5. The Moon answers by spiraling slowly outward, moving away by 3.8 centimeters a year. 6. Answering that it spirals inward would destroy angular momentum rather than conserve it. 7. Answering that it speeds up mistakes a wider orbit for a faster one, since distant bodies orbit slower. 8. Its rotation is untouched by this, and stays locked to its orbital period. _Source: OpenStax Astronomy (CC BY 4.0), Ch 4 "Earth, Moon, and Sky" and Ch 5 "Radiation and Spectra", section 4.6 Ocean Tides and the Moon_