An evil sorceror has cast a spell on the moon. Over the course of two years, it will seemingly disappear.

It will disappear from the surface inwards. Anything touching the surface shall be treated as part of the surface. This excludes light.

This occurs in the medieval period, so no pesky moon landings or anything.

What effect does this have on the earth, and the people living on it?

Obviously, diminished tides and stuff. But would there be seismic activity? Deaths? Extinctions? At what point do things really start changing?

EDIT: The timescale happens over a lot longer scale, so any changes would be far less drastic. Medieval technology would shape the effect on humanity a little more than the question the 'duplicate' is linking to.

  • $\begingroup$ I agree, everything described there would happen, only slower. $\endgroup$ – Mołot Feb 28 '18 at 7:22
  • $\begingroup$ In addition to the duplication, I've flagged this as "too broad" because it is asking for a list of side effects to a change centuries ago – geological, biological, historical, and sociological changes is a bit much to expect. $\endgroup$ – rek Feb 28 '18 at 8:07
  • $\begingroup$ @rek Many questions are in this format. $\endgroup$ – Piomicron Feb 28 '18 at 20:48

There is an interesting article that discusses this at a high level on the internet already and quite a bit of hypothesisation has already been done on this topic.

The key concern that we'd have is that the moon helps keep the Earth's axial tilt stable. This means that our existing concepts of weather, seasons and the like are based on that axial tilt. Without the moon, the Earth could rotate through 3 dimensions, not just two. Imagine a world where occasionally the north or south pole are facing the sun; if it was the south pole, you could end up with massive shifts in ocean levels. Obviously no tides, but that could also upset deep water currents which in turn could upset some of the key feeding cycles within the oceans, causing massive disruption to fish stocks and the like.

An unstable axial tilt would result in massive disruption to weather patterns, meaning that life on the planet would at best become far less comfortable for us, at worst untenable. These scenarios are of course speculative in places, but it's clear that the disruption to the earth would be much higher than just a simple lack of tides.

| improve this answer | |
  • $\begingroup$ However, it is to be noted that in this context "unstable" means "unstable over geological time spans", that is, unstable in the same sense that mountain ranges are ephemeral structures. $\endgroup$ – AlexP Feb 28 '18 at 4:12
  • $\begingroup$ This is true and it's not like the Earth would instantly spin onto its back or some other rapid shift. If that was the case, then it would have a massively detrimental impact to life on Earth, especially us delicate humans. $\endgroup$ – Tim B II Feb 28 '18 at 4:31
  • $\begingroup$ @TimBII Roughly how long would it be before this happened? Would it happen before 1600 years? $\endgroup$ – Piomicron Feb 28 '18 at 8:19
  • $\begingroup$ The obvious scientific answer is that we don't know for sure, but what we can do is look at Mars which has two much smaller moons meaning that the stability that we get from our Moon isn't reflected anywhere near as much on Mars. This link should give you some idea of what science is currently saying on that topic. $\endgroup$ – Tim B II Feb 28 '18 at 22:12

Not the answer you're looking for? Browse other questions tagged or ask your own question.