did you know the Moon is slowly moving away from us?

the Moon currently recedes from Earth by about 3.8 centimetres per year on average. the change is linked to tides and the exchange of angular momentum between Earth's spin and the Moon's orbit.

the Moon's gravity deforms Earth and its oceans. Earth rotates faster than the Moon orbits, and the tidal response creates a torque that transfers angular momentum outward to the lunar orbit.

Earth's rotation gradually slows through this interaction while the Moon's orbit expands. tidal friction also dissipates energy as heat, so this is not a perfectly reversible exchange.

scientists measure the distance using laser pulses reflected from equipment on the Moon. timing the round trip lets them track changes far smaller than the Earth–Moon separation itself.

at a constant illustrative rate of 3.8 centimetres per year, 80 years would add about 3.04 metres. that is tiny beside the Moon's average distance of roughly 384,400 kilometres.

3.8 cm/year × 80 years = 304 cm = 3.04 m

• no. tidal behaviour depends on ocean basins, Earth's rotation, and orbital configuration. today's rate is not a universal historical constant.
• the Moon also moves nearer and farther during each elliptical orbit. that monthly variation is separate from its slow long-term recession.