Moonless Skies: What would happen if the Moon suddenly disappeared?
Last Updated: August 29, 2023
The moon has been our constant companion for billions of years, lighting our way at night and helping us keep track of days, months, years, and important cultural traditions. But what would happen if it suddenly disappeared? Would it spell doom for us?
Let’s explore the impacts of the moon on Earth today by exploring what would be different if the moon disappeared and in the process better appreciate the various intricate forces at work that create the very normal world of today.
We’ll also explore the minuscule chance that something like this would happen.
Our natural satellite
The moon and Earth, as we know them today, are intricately intertwined. It was not always our constant companion, but became one pretty early on in the formation of our solar system when a Mars-sized object we call Theia impacted Earth a few million years after our sun began nuclear fusion and our solar system began forming from chaotic impacts. Instead of the two objects simply becoming one, a blob of debris was flung out in the collision and was caught in orbit around the Earth, eventually cooling into our Moon today.
Anything with mass has a gravitational impact on any other object with mass. The moon is only about a quarter the size of the Earth and is therefore caught in orbit around us, but that’s not where the interactions end. The moon also gravitationally impacts us in a variety of ways that have now become normal.
So, if it was all gone, what would change?
Our tides would be affected, which would affect much more
The moon’s gravitational pull causes the Earth and its water to bulge out on the side closest to the moon and the side farthest from it. The bulges are high tides while the water outside these two bulges experiences low tides.
While tides would still be present without the Moon since the Sun’s gravitational force also contributes to the tides, they would decrease to about 50-75% weaker than what they are today. While you may think this only impacts the gnarliest waves you can surf, the tides impact Earth in a variety of ways.
Tides churn up material in the ocean allowing coastal ecosystems to thrive with species such as crabs, mussels, starfish, and snails who all rely on the tides for food and general survival. Newly hatched sea turtles use the Moon’s light to find the ocean.
Silbery grunions time their biweekly mating rituals from March to August with the tides and their hatchling’s arrival coincides with the peak high tide. Considering that many of these species are already struggling due to humanity’s impact on the environment both in terms of habitat change (i.e. artificial lights) and climate change, this would only exacerbate the problem.
Domino effect for other ecosystems
Any impact on an ecosystem impacts other ecosystems, but especially when the target ecosystem is on the boundary of other ecosystems. Since coastal ecosystems are where the land meets the water, both of those ecosystems will also be affected, potentially leading to extinctions.
Since ocean currents are driven by the tides, they would also be impacted by the loss of our moon. Currents distribute warmer water around the globe and help regulate temperature, weather, and the climate of our planet as a whole over time.
With the drop in tides, ocean currents would be affected and potentially cause more extreme temperatures (both warm and cold) and weather (like hurricanes) around the world, but especially near the coast.
Both climate and ecosystems are complex, a combination of numerous factors globally over time. This makes any prediction about the climate or ecosystem future difficult and so knowing exactly how it would affect us immediately or years after the removal of an important factor like the moon is challenging, to say the least.
However, we can say that its long-term effects would impact current weather and ecosystems negatively which in turn negatively impacts us.
Animals around the globe would also be affected
Our seasons are caused by the tilt of our axis as we journey around the sun every year, meaning that parts of the globe receive more direct sunlight than other locations during different parts of our year. The precise tilt of 23.5 degrees relative to the plane on which we orbit the sun is largely due to the pull of the moon which keeps this tilt fairly steady.
Without the moon’s stable pull, our tilt could wobble much more, anywhere from 10 to 45 degrees. This wobble could displace our axial tilt so that Earth has no tilt which would mean no seasons (places would hardly see the sun at all while others would see the sun overhead for months on end) to an even greater tilt than now throughout the year, causing much more extreme weather patterns and even ice ages (some of our past ice ages were triggered by an axial tilt change of just one to two degrees).
This change wouldn’t be immediate and may not even have drastic effects within our lifetime, but it would particularly affect animals that have adapted for millions of years to survive in a very specific habitat with the current seasons. And again, as time goes on, these changes will increase in severity.
The pull from the Moon also has a long-term effect on the Earth in regards to time, increasing the length of our day by 2 milliseconds every century. While that means it won’t affect us for the foreseeable future, it will affect Earth and animals in millions and billions of years.
We would lose a repository of ancient knowledge and our closest neighbor
The moon holds a pristine record of the early solar system and Earth’s history due to a variety of factors including its ancient age, lack of an atmosphere, and lack of tectonic activity. Numerous studies have been done and are continuing today to study the history of Earth and the solar system by studying the history left behind on the moon through impacts over billions of years. If the moon were to disappear, the only traces of this history would be found in asteroids comets, and meteors.
The moon is our closest neighbor in space. While it took until the 70s to reliably travel to the moon and back, it has continued to be a source of knowledge and a popular target for missions (probes and orbiters since the Apollo missions). In addition, it is the first step in further human exploration of our solar system. We are finally sending humans back to the moon over the next two years (1st human landing since Apollo 17 is currently scheduled for 2025) to act as a training ground for sending humans to Mars.
In addition, permanent human occupation on both a lunar base and the Lunar Gateway station in orbit around the moon could help us overcome one of the biggest hurdles in space exploration: escaping Earth’s gravity since we could send materials to the Moon and then use its reduced gravity or even Gateway to launch.
Losing the moon would be a significant impact on our knowledge of the past and our potential for human exploration of the solar system.
Would humanity survive?
- In the short term? Yes.
- In the long term? Maybe.
As explained earlier, the effects on the global climate, ecosystems, and axial tilt are difficult to determine, especially in how they will all work together. Despite many harrowing reads on this subject, simulations imply that these changes would be gradual, but just how gradual is unclear.
With this gradual change, we would have the opportunity to make changes to our lifestyles, environment, etc. as well as hopefully positive changes for animals as well that would help us to weather the literal and figurative storms that would be coming our way. But we would have to dedicate resources to those changes over potentially long periods of time.
Historically, convincing changemakers to implement changes now to impact our environment and us in the future has not always been successful. Hopefully, the moon’s disappearance would be enough impetus to start making changes ASAP and continuing them.
What are the odds?
It would be quite the magic trick or a complete rewriting of physics as we know it for the moon to simply disappear one day.
So, does that mean this is impossible?
Scenario 1: The moon is impacted by a large object, nudging it out of our orbit. We’d likely get quite spectacular meteor showers and possibly some meteorite impacts depending on the object’s size, location of impact, angle of impact, etc.
But, it would probably be quite some time before the moon moved completely outside of our orbit, likely years, meaning we would have even more time to adapt a few aspects of living to help with the changes.
We also might be able to implement something similar to the recently successful DART mission to either intercept the object before it hit the moon if we knew it was coming or possibly nudge the moon back into orbit to reduce the effects.
What are the odds of this happening? Extremely low. As we discussed in our recent article on Near Earth Asteroids, there are currently no known asteroids that have a significant chance of impact with Earth or the moon in the next century.
Beyond that, we’re tracking a few asteroids that have a small chance of hitting Earth in the next few hundreds and thousands of years, but overall, the chance of an asteroid impact on either the Earth or the Moon is incredibly small.
Scenario 2: Just as the Moon has been slowing down our days for billions of years, the gravitational effects of the Sun, Earth, and Moon have also caused tidal effects on the moon as it is slowly being pushed away from us.
About 50 billion years from now, the moon’s orbit would be at its maximum reach, taking 47 days to complete an orbit around us and elongating our day to 47 current days. The Earth-moon system will equal itself out and cancel out tidal effects between each other. The Sun’s gravitational effects will continue, reversing the effect and pulling the moon slowly closer to Earth once again.
After another 50 billion years, it would be close enough to Earth to be torn to shreds by our gravity and create a ring of debris like the rings on Jupiter, Uranus, and Neptune (Saturn’s rings have a lot of ice and therefore reflect more light).
However, you may know or remember our previous article on the lifecycle of our Sun that our Sun will run out of fuel in 5 billion years and swell out to a red giant encompassing the orbits of all the inner planets except maybe Mars. So, we don’t have to worry about that gravitational interaction with the moon playing out.
The intricate workings of the Sun-Earth-Moon system create the world as we know it today. While it seems normal and even boring, an unimaginable amount of variables had to happen in our history for this to become the norm and the removal of any of these variables can mean drastic changes to life on Earth.
While only about a quarter the size of the Earth, the moon has significant gravitational impacts on us as well that have helped create our current climate, ecosystems, animal interactions and cycles, and more. All of these would be in jeopardy if the moon were to suddenly disappear. While changes would likely be gradual as opposed to instantaneous, it doesn’t mean that they would be insignificant.
Thankfully, the odds that this would happen range from extremely low to nonexistent. Instead, this thought experiment helps remind us of the numerous interactions that create normal life as we know it today and the tenuous threads that form it.
If you enjoyed this thought experiment, consider checking this one out: What would happen if the sun exploded?
Sarah Hoffschwelle is a freelance writer who covers a combination of topics including astronomy, general science and STEM, self-development, art, and societal commentary. In the past, Sarah worked in educational nonprofits providing free-choice learning experiences for audiences ages 2-99. As a lifelong space nerd, she loves sharing the universe with others through her words. She currently writes on Medium at https://medium.com/@sarah-marie and authors self-help and children’s books.
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