What Would Happen If the Moon Disappeared?
On the 50th anniversary of the Apollo 11 astronauts' moonwalk, we ask, What would happen if there were suddenly no moon?
Anniversary of the moonwalk
On July 20, 1969, Apollo 11 astronauts Buzz Aldrin and Neil Armstrong became the first people to ever walk on the surface of the Moon, some 240,000 miles from Earth in a part of our planet’s atmosphere called the geocorona. We’ve had 50 years to get used to the fact of that first amazing moonwalk, on an astronomical body whose presence outside our window on most evenings we also take completely for granted, even if we’re still not sure how it was created. But what would happen—to our planet and its tides, its tilt, its climate—if one day the Moon just vanished? And what would happen to us? Let’s take a look.
Dark would be darker
It’s hard to know what order the effects of the moon’s disappearance would be, but PopSci speculates that one of the first changes humans would notice would be darker nights. Why? Because the moon reflects the sun and provides some amount of brightness to us when the sun is on the other side of our planet, especially on nights of a full moon—the same kinds of nights that mess with our emotions.
Driving would be less safe
The result of the extra nighttime darkness? Its effects on modern human society would be felt, in some places more than others. As PopSci explains it, without the sun’s indirect glow on the moon, “any areas that don’t have access to artificial light, like country roads or wooded campsites, would become far riskier to travel through at night.” On the other hand, without the Moon’s light, according to Forbes, there would no longer be any impediment to our enjoyment of a full-star sky on clear nights.
Pros and cons for land animals
What would the effect of these nights be on animals? It depends on the animal. “Many predators, like owls and lions, rely on the cover of darkness with just a bit of moonlight to hunt effectively,” points out PopSci. “With no moon, they would have trouble finding food. Rodents, on the other hand, tend to hide more when the moonlight is strong. It’s easier for their predators to detect them. With no moon, they would thrive.”
Tides would be smaller
Because of the gravitational pull of the moon, we get high tides and low tides. The ocean the moon is closest to at any given time gets “a bonus gravitational pull, so it rises up slightly,” says LiveScience. Some proportion of our tides are caused by the pull of the sun, but without the moon, our tides would be much smaller—about 1/3 smaller, estimates the Royal Museum of Greenwich (RMG). Learn even more crazy facts about the Earth you never knew.
No tides, no tidal ecosystem, and that means that all the animals that live in such an environment would be doomed—creating an extinction spiral. “Tides churn up material in the oceans, which allows coastal ecosystems to thrive…[and] crabs, mussels, starfish, snails rely on the tides for survival,” according to RMG. It’s a whole essential web of marine life. And points out PopSci, “These ecosystems in turn feed migrating and local birds as well as land mammals like bears, raccoons, and deer.”
Worsening climate change
Believe it or not, tides also stabilize our climate. With smaller tides, that climate would become a lot more unpredictable than it already is: “Tidal movements…help drive ocean currents, which in turn direct global weather patterns, as the currents distribute warm water and precipitation across the globe. Without them, regional temperatures would be much more extreme; as would major weather events,” says PopSci.
Earth is tilted on its axis at around 23.4 degrees (although this varies somewhat), and the moon helps keep that stable. Worlds without big moons, like Mars, points out Forbes, “see their axial tilt change by ten times as much over time. On Earth, without a moon, it’s estimated that our tilt would possibly even exceed 45° at times, making us a world that spun on our sides.” Learn even more astronomy facts you never learned in school.
So, what’s so awful about the Earth spinning on its side? Says Forbes, it would mean that “Poles wouldn’t always be cold; the equator might not always be warm. Without our moon to stabilize us, ice ages would preferentially hit different parts of our world every few thousand years.” In short, spring, summer, fall, and winter would lose all their meaning.
The moon is also partly responsible for our 24-hour days. “Without the moon, a day on earth would only last six to 12 hours,” shares an article on Inside Science. “There could be more than a thousand days in one year! That’s because the Earth’s rotation slows down over time thanks to the gravitational force—or pull of the moon—and without it, days would go by in a blink.”
Planetary nervous breakdown
That’s how Bhanarkar envisions another effect of the loss of gravitational pull from the moon on life on Earth. Without that pull, also known as flexing, “the core of the planet might feel some awkward shifting. That could set off any number of very, very bad things like earthquakes or volcanoes,” he theorizes. Here are some more science mysteries no one has been able to explain.
More susceptible to asteroids
You know that a massive asteroid hitting the Earth 66 million years ago was responsible for the extinction of the dinosaurs and so much other life on our planet. But what you might not realize is that the Moon could actually act as a first line of defense for us, against other objects hurtling through space. Without the moon “stopping some [asteroids that] might otherwise make their way down here, we’d be in the line of fire,” Bhanarkar speculates.
Say we miraculously survived all of the above. It’s the more inspirational, aspirational things in our lives here on Earth that would suffer without the moon. As NASA gets ready to try to launch humans to Mars, it’s looking at the moon as a stopping point along the way, as a means to make the 34 million mile journey a little shorter and more efficient. Without the moon, “We would no longer have our stepping stone to the rest of the universe,” says Forbes.
Less science generally
As Matt Siegler, a research scientist at NASA’s Jet Propulsion Laboratory told PopSci, studying the moon has allowed us to understand much about our home planet and our place in the universe. “We’re pretty lucky to have had the moon there as an easy destination to go for,” Siegler said. Without it, “There’d be a lot of information we’d just miss out on.” Read on to learn about 14 more of the most baffling mysteries in the universe.