By Ainsley Benbow
The moon is not just the largest visible object in our night sky, known for its celestial beauty and true aesthetics. It also has a significant role within our everyday life and the survival of our planet, Earth. The delicate dance in the cosmos connecting these astronomical objects is more than meets the eye, or the camera lens at sunset.
About 4.5 billion years ago when a collision occurred between the earth and another small planet, the resulting debris compacted to create an object orbiting around earth, later becoming the moon. Many scientists, including Thomas Harriot, Galileo, and Robert Hooke, have been fascinated by the layout, mappings, movement, and impact of the moon across time.
Despite the moon being roughly 27% of the Earth’s size, it has a tremendous effect on the stability of Earth’s axis, tides, seasonal changes, and ecosystems. Without the moon, these features would cease to exist, or create fierce extremes unlike anything we have ever seen before.
Over time however, there has also been increasing knowledge regarding the gradual movement of the moon away from the Earth. This has been recognised since the mid-1970s, as new technologies revealed something that had been occurring for the past 4.5 billion years.
During the 1970s, United States and Soviet Union missions confirmed that the moon is moving away from the Earth at a rate of 3.78-3.82cm per year. They did this by using laser technology to view how laser beams bounced off mirrors from the moon. This allowed researchers to measure the time it takes to receive a signal from the distance between the two celestial bodies. Interestingly, nearly 300 years prior, this had been hypothesised by Edmond Halley, an English astronomer, who suspected the movement of the moon after studying records of ancient eclipses.
This gradual drift away from the Earth is called ‘Lunar Recession’, which is caused by the rotation of the moon and Earth. It is essentially a tug-of-war between the forces exerted by the moon and Earth, as they both have a gravitational force against one another. This causes the moon's orbit to become elliptical rather than a perfect circle, meaning it has a greater distance from the Earth, because sometimes the moon is closer to the Earth in some parts but farther away in others.
As the distance between the Earth and moon gets smaller in different areas of the eclipse, the force is stronger as they are closer together and therefore enables the moon to accelerate slightly, moving it ahead of its predicted position caused by the ellipse shape. Eventually, the moon slows down because of the gravitational tug of bulge caused by the force of the moon with Earth’s ocean waters in which then, it moves farther away from Earth.
This continuous battle between stronger and weaker gravitational forces in the moon's orbit makes its size gradually increase, causing the moon to move farther and farther away. However, this rate of Lunar Recession is not constant and depends on numerous other factors including tidal forces.
Even though the consequences of casual drift will not impact us immediately, it is still important to understand the moon's impact on our world and what could happen in a future without it, with ‘the future’ being 5-10 billion years from now.
One of the greatest impacts the moon has on our world is its ability to influence tides. The tidal force lies between the moon and Earth as a result of their gravitational pull’s exertion, resulting in the formation of tides on Earth's surface. Even though the moon and Earth both attract one another in the solar system because of gravity, the moon orbits the Earth because it is much smaller in mass compared to the Earth, which only causes little effects.
This ‘little’ effect is called bulging, which is where whatever side of the Earth the moon is facing, experiences the bulging effect from the moon, attracting and producing the waves, as shown below.
There are high tides when bulges are high, and low tides when it is low. Without the moon’s presence in orbit, they will become smaller and less frequent. These are vital for the preservation of marine ecosystems, which depend on the tides and currents for survival. As such, lessening tides would drastically change the face of the Earth because of the possible mass extinctions in marine life and across entire ecosystems. It would also alter landforms along coastal regions, impacting human activities, possibly the economy, and heighten frequencies of unsafe oceans.
Continuing this, the ocean’s role in renewable energy is substantial and without our precious moon, this source of clean, sustainable energy, is lost. Renewable energy can not only benefit our access to energy, but also allows us to receive this energy, without the amount of pollution and production of greenhouse gases emitted into our atmosphere. Some of the most popularised and effective forms of renewable energy include wind energy, solar energy, hydropower energy, geothermal energy, and tidal energy. Tidal energy is “power produced by the surge of ocean waters during the rise and fall of tides,” as stated by the National Geographic Society.
Without the companionship of the moon orbiting the Earth and playing a vital role in controlling the ocean tides, it limits our access to this source of energy. Also, tidal energy is a much smaller contributor to the production of energy in our world, the degradation of wildlife and the environment from the seasonal changes faced with the moon’s disappearance, could lead to other renewable and non-renewable energy sources be met with fierce resistance for continuation.
The ocean, as we have learnt, is not just a fun place to tan alongside your friends or ‘accidentally’ push your brother into a moon driven tidal wave, but instead is a perfect example of the moon’s impact on Earth. Not only from its tides, but the ocean currents prove to display these effects as without the moon, it could disrupt ocean systems, global weather patterns and temperature and precipitation patterns which then results in the extreme consequences of droughts, floods, etc.
The moon's role in our solar system continues to impact our livelihood and survival by also helping to regulate the distribution of sunlight across Earth which supports agriculture, plays an essential role in migration and navigation for many animals, as well as, the navigation of ships, boats, and industries relying on the ocean for fishing and much more. Additionally, without the moon’s protection from the lunar gravity blocking asteroids from coming into our atmosphere, Earth’s vulnerability would increase immensely by the lack of deflection. This displays the vulnerabilities of the Earth globally, because of the moon’s possible disappearance.
An interesting concept is the effect on nocturnal land animals, instead of on sea creatures from tides in the oceans. As the moon gets its light from the sun, reflecting a fraction of the light and absorbing the rest, it allows for many prey animals to seek shelter and survival from predators in the wild as most use their eyesight as their primary sensory system.
The brightness increases the activity of these prey animals, which suppresses the activity of other species such as bats who eat at night. Without the light provided from the moon, ecosystems would quickly turn into places of unbalanced predatory domination.
Without the moon, the Earth would also have nothing to stabilise its tilt, which could result in less stability in time and seasons due to the large tilt increasing weather extremes and possibly ice ages. This can result in possible mass extinctions of flora, fauna, and the entire human race.
Luckily, none of these POSSIBLE effects will occur anytime soon and not for the next couple billion years! Even then, the moon will still exist in our solar system and night sky as it moves very slowly and will not just suddenly disappear one night! It will have to be completely out of our sight, or until it gets too far away, for there to be any completely deadly threat… I hope.
In conclusion, even from orbiting at an average distance of 384,400km, the moon’s influence in our society and global security is highly overlooked! Its presence in our solar system not only stabilises our planet, but allows it to flow with tides and beam in sunlight both during the day and night.
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