the moon is leaving

If you applied a coat of paint to the bottom of your shoes every single day, one coat on top of the other, every morning, you would leave Earth just as quickly as our moon is leaving us. Every day, the moon moves about a tenth of a millimeter away from Earth. It's 3.8 centimeters further away from us every year. That's about the length of an air pod.

The Moon is leaving us because the world is turning. The moon's gravity causes the Earth to slightly bulge, but because the Earth rotates in the same direction as the moon's orbit, the bulge tugs on the moon, speeding it up. And the faster something moves tangentially to a gravitational pull, the more successfully it escapes that gravity and the further out it orbits.

The moon's equal and opposite pull on the bulge slows down Earth's rotation. If the Earth and Moon survive the death of our sun 5 billion years from now, 45 billion years after that, they will be tidally locked to each other. For half of the Earth, the moon will appear permanently fixed to a point in the sky, and the other half will never see the moon again.

Thank you.