Why the Moon Doesn’t Crash Now#

First off, let’s cover the basics. Why isn’t the Moon already falling towards us?

• We know Earth’s gravity pulls everything towards it, and that includes the Moon.
• But the Moon stays up, almost like something is holding it there.
• There isn’t another force pushing it away. The real trick is its sideways movement, which we call an orbit.
• You actually see orbits every day! When you throw a ball, it makes a tiny orbit.
• The only difference between your ball and the Moon is that the ball eventually hits the ground.
• This is because of speed. If you could throw your ball fast enough, it would curve around the world and come back to you. If there was no air to slow it down, it could orbit forever.
• This is exactly what the Moon does: it’s constantly falling sideways around the Earth, moving very fast (3,600 km an hour) with no air to slow it down.
• It completes one orbit every 27 days.

So, for the Moon to just stop and drop would break more physics laws than we have time to talk about!

Making the Moon Fall: A “Magic Spell”#

How do we even make it crash?

• To change something’s orbit, you need to change its speed. Changing speed changes where gravity takes it.
• But even small changes need huge forces, which is why the big objects in our solar system are so stable.
• Science tells us the Moon is massive. Even putting billions of rocket engines all over it would barely budge it.
• It seems like nothing short of magic would make the Moon fall.
• So, for our scenario, we’ll use a “magic spell” that slows the Moon down so much that its orbit changes, and it spirals towards Earth.
• To make things interesting, this journey will take exactly one year before it hits Earth.

Alright, here we go… 3, 2, 1… Magic!

The First Few Months: The Approach#

Let’s track what happens month by month as the Moon gets closer.

Month 1:

• For the first few days, not much seems different.
• The Moon gets just a tiny bit brighter.
• Scientists might get confused, but most people won’t notice anything.
• The main real effect the Moon has on Earth is tides.
• Tides happen because while Earth pulls on the Moon, the Moon’s gravity pulls back on Earth.
• Since gravity gets weaker the further away you are, different parts of Earth feel a slightly different pull.
• This causes Earth, especially the oceans, to bulge when the Moon is overhead and shrink slightly on the sides.
• As Earth spins daily under the Moon, the Moon’s pull changes, making ocean water levels rise and fall by about half a meter, twice a day.
• But with the Moon now getting closer, high tide starts getting higher every day.
• At first, you barely notice.
• Within a month, the Moon has covered half the distance to Earth.
• Ocean tides have grown to 4 meters every day.
• During high tide, waves flood coastal cities and there’s no sign of it stopping.
• As the Moon keeps getting closer, tides keep getting higher, flooding more cities and inhabited land with salty water every single day.

Month 2:

• By the end of month two, the Moon is 2/3 of the way to Earth.
• Global infrastructure starts falling apart.
• Tides are now over 10 meters high.
• Up to a billion people who live near the coastlines are displaced.
• Ports can’t be used anymore, and shipping stops.
• This won’t just slow down things like “quazar products” (whatever those are!), but also essential stuff like food.
• Global communications get messed up.
• 95% of the internet travels through cables under the ocean. While the cables themselves are mostly fine with water, the buildings on land where they connect are not.
• Even living inland isn’t safe. Tidal surges push rivers backwards, carrying salt water inland. This contaminates surface water and underground water supplies.
• Gas shortages happen because all the refineries near the coast are abandoned.
• Countries only have the supplies they had sitting around, and strict rationing starts in cities.
• Total chaos takes over during the times of low tide when people try to scavenge.
• Survivors hide in tall buildings when the water comes back for high tide.

Month 3:

• Three months in, the Moon is close enough to mess up our communication and navigation satellites.
• Normally, it’s too far away for its gravity to cause any problems for satellites.
• But the closer it gets, the more twisted their orbits become.
• Satellites run out of fuel they use to correct their paths.
• They start flying around out of control.

Months 4 and 5:

• Down on Earth, the tides are rapidly growing to about 30 meters high.
• They will reach 100 meters high in just a few weeks.
• At low tide, the ocean pulls back hundreds of kilometers, showing the sea floor near the continents like huge deserts.
• At high tide, walls of water drown farmland, houses, and even skyscrapers.
• Now, almost 5 months in, the “apocalypse” phase has finished its warm-up.
• Since the oceans are only about 3 km deep on average, the water tides have reached their maximum height.
• Until now, the water could move around and absorb most of the Moon’s gravitational squeezing.
• But now, Earth itself is feeling the squeeze from the approaching Moon.
• These aren’t just water tides now, but tides of rock.
• The planet being squeezed, plus the weight of massive amounts of water sloshing on and off the tectonic plates, creates enormous pressure deep down.
• This starts causing earthquakes that are getting bigger and stronger.
• It’s impossible to say exactly how bad or where these earthquakes will hit, but like a kid jumping on a bed until it breaks, it’s not going to end well.
• Strong tidal forces cause volcanoes on other planets and moons. On Earth, squeezing the planet messes with the pools of melted rock inside the crust.
• This triggers big volcanic eruptions that can change the climate, like in Chile, New Zealand, Yellowstone, and other places.
• Meanwhile, looking down patiently is the Moon. It’s still not bigger in the sky than a small cloud.
• When it gets within 75,000 km of Earth, it’s bright enough to light up the night sky like it’s twilight.

Halfway There and Beyond#

Months 6 and 7:

• After six months, the Moon is entering the space where geosynchronous satellites used to be.
• Here, it orbits Earth every 24 hours.
• It looks like it’s just floating in one spot in the sky, not moving.
• It goes through all its phases every day, but you can only see it from half the planet.
• With the Moon stuck above one part of Earth, the tides seem to freeze in place.
• Half the world is flooded, and half seems to have its water back as if Earth is holding its breath, getting ready for the worst.
• As the Moon gets even closer, you might wonder if its gravity would become stronger than Earth’s, pulling you up.
• Luckily, that won’t happen. Earth’s surface gravity is about six times stronger than the Moon’s. So even if the Moon was right above you, you’d stay on the ground.
• Things are different on the Moon, though. The side of the Moon facing Earth is pulled more strongly by Earth’s gravity.
• Over the next few months, it starts to stretch towards Earth, becoming somewhat egg-shaped.
• This causes deep moonquakes as the lunar rock bends and changes shape.
• You might barely notice this stretching at first, but it will grow to hundreds of kilometers in just a few months.

Months 8 to 11:

• At this point, the full apocalypse has arrived.
• We can sum up these months before the crash by saying: everyone left is having a bad time.
• The tides that were sweeping over Earth slow down and then reverse direction. This is because the Moon now orbits Earth faster than the planet rotates.
• The planet keeps having lots of earthquakes and volcanism.
• Huge amounts of stuff from volcanoes (aerosols) go high into the stratosphere. They are shiny and reflect sunlight back into space.
• What little light does get through is reddish-brown.
• This light is also blocked periodically by daily eclipses.
• The result is rapid global cooling.
• There’s acid rain and even summer snows, killing off even the toughest plants.
• Civilization is basically over. Billions have died.
• An “x-shaped” Moon is still getting closer.

The Grand Finale: Month 12 and Aftermath#

Let’s get ready for the end.

Month 12: The Crash (Sort Of)

• Finally, at the end of the year, the Moon reaches the Roche limit.
• This is the point where Earth’s gravitational pull on the Moon is stronger than the Moon’s own gravity holding itself together.
• Things on the Moon’s surface start falling towards Earth.
• By the time it crosses 10,000 km, the whole Moon breaks apart into rubble.
• It smears itself out into a massive ring system around Earth.

Aftermath:

• Luckily, the Moon breaking apart means the absolute worst misery on Earth stops.
• No Moon means the general apocalyptic problems calm down.
• The oceans pull back, flowing off the land one last time.
• Any survivors are treated to an amazing sight: huge arches stretching across the sky.
• These rings glimmer in the sunlight and light up the night sky much more brilliantly than any full Moon ever could.
• The sky is also filled with meteor showers made of Moon dust.
• It’s hard to say exactly what happens next. The calm might not last long.
• If too much Moon dust falls down, friction could heat the atmosphere, possibly boiling the oceans.
• If that doesn’t happen, the enormous shadows cast by the rings, combined with all the stuff from volcanoes and the meteor dust, block even more sunlight.
• This could start a period of unstoppable cooling, freezing much of Earth’s surface solid.
• Anyway, at some point, people might come out again from submarines, bunkers, or mountain tops.
• They won’t have an easy time of it before trying to rebuild civilization.
• Their success isn’t guaranteed.
• But at least they’ll be trying under the sight of beautiful rings in the sky.