What would happen if we lost our moon? Asked via Facebook
No moon? What an Apollo-ing notion! (Forgive me…) In short: without a moon, things would get messy – although it may take a few thousand years for it to really sink in. The moon does three important things on the Earth: it controls its tides, its rotation and its wobble. By pulling at our oceans with its gravity, the moon gives us high tides. (The sun does a similar thing, but because it’s so much further away it doesn’t affect the tides as much.) So without the moon, tides would be less pronounced. Such a change wouldn’t sole- ly affect fishermen (get it?! Ok, I’ll stop now) – but also many animals that depend on changing tides to survive. Mass extinctions wouldn’t be great for the planet, but it wouldn’t cause the world to come to an end. The moon also puts a damper on the Earth’s spinning speed, causing it to ever-so-slightly slow down. This is called tidal friction and, thanks to the moon, our days are actually becoming gradually longer. Without our moon, days would gradually become shorter. This wouldn’t be too much of a bother though, as we would lose only a couple of seconds every 100,000 years. Losing the moon would mean losing the Earth’s stability: our planet wobbles as it orbits around the sun and the moon reduces this wobble. The physics behind this is a bit too complex to go into, but the result would be greater fluctuations in the Earth’s day lengths; there would be periods with no seasons, and times of seasonal weather extremes. Changes would still be quite gradual though, so we’d have some time before extreme climate change would put an end to our reign on Earth.