What Would Happen If the Moon Suddenly Disappeared?

VOICE OVER: Ashley Bowman WRITTEN BY: Nathan Sharp
Few things feel more fundamental to life on Earth than having the moon light up the night sky. For centuries it has inspired, bemused and intrigued scientists and philosophers. And it plays a vital role in the way our planet works. But, what if the moon disappeared? What if our lunar neighbour simply switched itself off and vacated the solar system? What then??

What Would Happen If the Moon Suddenly Disappeared?

The Moon has been our cosmic companion for over four and a half billion years. But, it’s more than just a giant rock floating alongside us and brightening the night sky. And if it ever disappeared, life on Earth would be irreparably changed.

Fundamentally, the Moon helps to keep our planet in place, therefore ensuring that life can even develop here. Earth is actually prone to a very slight (though potentially devastating) ‘wobble’ every now and then, with past ‘wobbles’ being blamed for various ice ages. However, the movement would be much more severe if it wasn’t for the Moon, which acts as a stabilizer, using the gravitational force to stop the Earth from shifting more dangerously. So, first things first, without the Moon it’s been hypothesized that the Earth's axial tilt could alter by as much as 85 degrees – which would make meteorological mincemeat out of everything we know. That’s a worst-case scenario, though.

Back down on the ground – or in the oceans – the Moon also plays a direct role in how Earth operates, and its influence mostly boils down to the gravitational force it exerts. Given that the Moon is A) much smaller than Earth and B) about 384,400 kilometres away from us, its gravity isn’t nearly strong enough to pull our planet towards it – but it does, essentially, stretch us out.

While it’s in no way noticeable to us, the Moon subtly pulls at whichever side of Earth is currently facing it – causing high and low tides. However, this ‘stretching’ phenomenon not only affects how long we can spend sunning ourselves at the beach, but is also responsible for various biological rhythms within our bodies, and for the formation of specific ecosystems. Take the moon away, and the tides would mostly disappear with it. Although, the Sun’s gravitational pull is responsible for a smaller percentage of Earthly tidal force – so there’d still be some slight movement.

Of course, it’s not just the world we stand on that’d be affected. The Moon also directly influences us, human beings. And, no we're not talking about lycanthropy (or werewolves) either. In reality, a full Moon can affect those with advanced photosensitive epilepsy due to the brightness of the night sky. Meanwhile, a 2017 study published by The BMJ found that there’s a 5.3% increase in motorcycle fatalities during a full Moon, likely due to the visual distraction and reflections. Some scientists refute claims that the full Moon affects menstruation and sleep quality, but there are clearly some benefits for a moonless sky – in terms of lessening road accidents at least.

Removing the brightness of the Moon may have other affects, too. According to most astronomers, the best time to go stargazing is when there’s a New Moon – when the skies are at their darkest. So, if counting constellations is what you’re interested in, then your task gets a lot easier if the Moon suddenly disappears for good. However, while the night sky may be clearer, you’d have much less time to enjoy it…

That’s because a lack of moon would cause our days (and nights) to shorten. As in, literally last for less time than they do now. Back when the Earth first formed, a day was less than six hours long. But, over time, tidal friction (the tugging between the Earth and the oceans) has slowed down the rotation of the Earth – pushing us to our current 24-hour cycle. Should the Moon suddenly up and leave, then we’d have nothing to slow us down, and our day/night cycles would gradually shorten once again.

Next, local ecosystems would fall completely out of whack. A 2013 study published in The Journal of Animal Ecology found that animals with vision as their dominant sense – ranging from lions to tigers to eagles – rely heavily on the presence of the Moon, which creates a contrast in the darkness so they can successfully hunt and hide. Take away that contrast, and the predators especially would be at a major disadvantage – leading to a collapse in local food chains, and a possible upsurge in prey (such as rodents) due to their natural hunter’s gradual extinction. In amongst all of the tidal changes and axial shunts, we’d also have a world riddled with rats, mice and safely-scurrying creepy crawlies.

Aquatic ecosystems would go through similar upheaval – and here we head back to that most obvious of changes in a Moonless existence, the tides. Various species of marine animal – including crabs, snails, mussels, and barnacles – live within the area between high tide and low tide. These species rely on the persistent and guaranteed flow of water for their survival. But, without it, and without the natural supply of resources and minerals that it brings, they’d also go extinct. And then, yet more food chains are destroyed as a domino effect sets in, where migrating birds can’t feed, a main food source for land mammals dries up, and so on.

Over time, regional climates would also begin to change without the Moon, growing more extreme. Again, it’d mostly be down to the disappearing tides, as ocean movement contributes immeasurably toward moving weather systems around the world – dictating what types of weather reach certain locations at certain times. As about 71% of Earth’s entire area is covered by water, our oceans also absorb the majority of sunlight that reaches us. On the one hand, the seas evaporate and create areas of extreme humidity or dryness. On the other, they act as a global blender that distributes sunlight – bringing warm water and rain from the equator to the poles, and bringing back cold water to equatorial regions.

Without this ‘blending’, the sun’s radiation would be unequally spread, resulting in severe and unpredictable conditions. Temperatures would essentially stagnate, with no escape from the dry, biting, icy lows in polar regions, or the sweltering, humid highs along the equator. Before long, there’d be mass migration around the globe. That is, if we are still here.

Which brings us back to our worst-case scenario, and the more fundamental changes that Earth would go through. First, there’d be a ‘wobble’ without the Moon, but eventually our world could find itself growing attached to other Solar System planets such as Venus or Jupiter – tilting it in their direction in the absence of the Moon. This would create destabilization to supersede anything that a slowing of the tides could incur… as Earth winds up at the centre of a massive tug-of-war between its nearest neighbours.

From here, without the Moon, it’s slow pandemonium – with the axial tilt becoming more and more unpredictable. Antarctica could find itself facing the Sun, pulled that way by some passing body that definitely isn’t the Moon, resulting in melted ice caps and massive flooding. Rainforests could find themselves drying out, and deserts could become the coldest places around. It’d all unfold across Millenia, and the planet more than likely would survive – but how about the human race? We’re a hardy species, but could we really deal with the worldwide chaos that the Moon’s disappearance would bring? What do you think?