What Would Really Happen If The Moon Disappeared?

The moon has long-fascinated humans, and its effects on the earth are continuously researched. Scientists believe Earth got its moon around 4.5 billion years ago, after a celestial body collided with the newly formed planet. As a result, the moon itself is part Earth and part mystery impactor. Since its formation, the moon has stuck near Earth ever since, and the two continue to push and pull one another via the force of gravity.

It's easy to see how the sun influences the Earth, but the moon also plays numerous roles in how the planet functions. This can influence daylight hours, seasonal changes, ocean tides, and many other everyday occurrences we take for granted. Indeed, without Earth's moon, life would look much different on this planet, and some species might not be able to exist at all. It's impossible to know exactly how Earth might behave were the moon to disappear, but researchers do have several hypotheses on the subject that are both fascinating and a little terrifying.

Changes between winter, spring, summer, and autumn occur every year, but it's easy to take these entities for granted without thinking about the causes of the four seasons on Earth. These important changes are all the result of the tilt of the Earth as it revolves around the sun. On average, Earth tilts 23.5 degrees, which means the poles never face the sun directly head-on. This constant tilt during rotation around the sun is also responsible for seasons on the planet.

While it's easy to assume the sun is the biggest player in Earth's seasons, none of this would be possible without the moon. In fact, scientists believe the impact between the moon and Earth is what gave the latter its enduring 23.5-degree tilt. What's more, the gravitational pull between the moon and Earth helps stabilize this tilt and prevents the North Pole from pointing at the sun. If there were no moon, the lack of stability could lead to erratic weather and unpredictable seasonal patterns on Earth.

Aside from seasonal changes that influence the amount of daylight you experience during certain times of the year, it's also possible that a lack of moon could create shorter days more generally. Daylight hours on Earth are impacted by two major factors: the way the planet orbits around the sun, as well as your specific latitude. On average, Earth spins its axis one time every 24 hours as it makes its journey around the sun, but the spinning rate used to be much faster. The rate of orbit has slowed down significantly thanks to the moon. In fact, scientists believe the moon relies on Earth for its spin energy, which in turn decreases the rates of speed for both. The moon also continues to move away from the Earth 2 inches annually, which can slow spinning motions even further.

It's estimated that the average day on Earth was only six hours long until the moon began slowing down the planet's rotational speed about 4.5 billion years ago. For comparison, scientists believe that 650 million years ago, the average day was 22 hours long. In fact, if you're wondering if days will get longer or shorter, know that the days are still gradually getting longer due to the gravitational pull between Earth and the moon.

Tides in the ocean are dictated by both the sun and the moon. However, the moon has the greatest influence due to its close proximity with the Earth, as the sun is 390 times further away. While the moon isn't the only entity that affects ocean tides, it does play a large role by creating high and low tide cycles due to its gravitational relationship with the Earth. With each gravitational tug, Earth subtly elongates around the equator, which can then create ocean tides. At the same time, the Earth continues its normal rotation. These two entities contribute to the two high tide and low tide cycles you might observe along an ocean shore each day.

Needless to say, without a moon, these oceanic tidal patterns could cease to exist. High tide cycles would no longer emerge from the elongation of the Earth from the moon's slight pull. Overall, the tidal patterns would be much smaller—an estimated third of their size today. Without these high tide cycles, water could not churn in Earth's oceans, potentially disrupting several marine animals, including mussels and crabs. Ecosystem disruptions could lead to extinctions. What's more, ocean tides help push warmer waters around the globe. This process could become stagnant without the help of the moon, adversely affecting Earth's climate.

Aside from disrupted ocean tides, there are other ways the moon's absence could negatively impact Earth's climate. Without the stabilizing effects of the moon, Earth could experience drastic climate changes, such as extreme cold and heat at each of the poles. This again all comes down to the gravitational pull of the moon. Scientists believe the moon acts as a climate stabilizer because of the way it helps the Earth move smoothly and consistently. Without these effects, the planet could wobble around with no clear rotational patterns.

While it is difficult to predict exactly what Earth's climate might look like without a moon, it is worth looking at two planets in our solar system that do not have moons for comparison. These include Venus and Mercury. In particular, Venus is the hottest planet, and there are no differences between night and day. The average surface temperature measures at 869 degrees Fahrenheit, thanks to its close proximity to the sun and its inability to ever tilt more than 3 degrees at a time. Given how far Earth is from Venus, it is hard to say whether a moon would make a significant difference in this neighboring planet.

While humans might technically survive without a moon, not all species might be so lucky. In particular, nocturnal predatory species could be impacted the most. This includes those who might rely on moonlight to help them hunt at night, as well as animals with good night vision such as wolves and owls. An inability to see and to find food or to hide in the dark from prey could lead to devastating extinctions for some of these animals. What's more, the natural ecosystem might change due to an overabundance of prey.

Aside from the light of the moon, certain species on Earth have evolved in a way that makes them dependent on the moon's cycles for other biological necessities. Salmon migration patterns are one example. While salmon tend to migrate to the ocean under the dark cover of a new moon, they tend to wait upstream in rivers during a full moon. In theory, if the moon disappeared, this could cause confusion among salmon who might not ever stay in rivers. This could cause disruptions in the population, as well as affect humans who fish for them. A lack of a moon could also spell trouble for several ocean species who rely on the light of a full moon for reproduction. Among these include coral, mussels, and some types of fish.