What if the earth had no moon?

Author: Alice Gerth

The Moon has had an enormous effect on the development of our planet and human life. The effects can be divided into two areas: our physical evolution and intellectual evolution with the development of mathematics and science. The Moon was formed some 4.5 billion years ago, 5 million years after the Earth was formed. The most accepted theory of the creation of the Moon is that at this time large amounts of debris rotated in the same orbit as the Earth. The Earth collided with a piece of this debris about the size of Mars. This caused the Earth’s surface to melt and a large proportion of the debris became incorporated into the Earth. The rest of the debris formed the Moon. This resulted in the Earth increasing in size and hence a greater mass and gravitational strength, which might have produced a thicker atmosphere. This thicker atmosphere helps to keep the Earth warm and protect it from radiation. It also affected our orbit but as scientists do not know the exact details of the impact they are not sure of what manner. This is chronologically the first impact (both literally and metaphorically) the Moon had upon the conditions on Earth.

The most obvious effect the Moon has on the Earth is the tides. The Sun also affects the tides but only a third as much as the Moon. The tides at the Moon’s creation were greater because the Moon was closer to the Earth. The tides had two effects: firstly, the ebb and flow of the tides slowed down the Earth’s rotation from 8 hours to the 24 hours we have today. If it rotated three times faster, the Earth would experience huge storms similar to those on Saturn. These conditions may have been too extreme for life to develop on land. The rotation of the Earth also affects the Earth’s magnetic field. The magnetic field is due to the Earth’s rotation which causes currents within the mantle. This magnetic field reacts with a solar wind to form the magnetosphere; the magnetosphere is above the radiation belt. This magnetic field limits the amount of radiation as it holds the electrons and protons supplied by cosmic rays in the radiation belt, on spiraling paths along the lines of the geomagnetic field. If the Earth was spinning faster, the magnetic field would be greater resulting in less radiation and thus, less mutation.

The ebb and flow of the tides has had an even more direct effect upon the development of life on land. The ebb and flow of the tides resulted in sea creatures being washed ashore. The majority of these did not survive due to the different atmospheric pressure, the need to draw oxygen out of air, the extremes of temperature in comparison to the sea and the need to find water. However, gradually, over millions of years, some life forms started to evolve. 425 million years ago, plant life began to spread across the continents. This was followed by spiders, snails and other small insects. 400 million years ago came the amphibious creatures. Man is believed to have evolved from fresh water ponds. These organisms adapted to life on land due to the drying out of ponds. The ebb and flow of the tides, however, is what provided the ecology that these organisms would rely on for life.

Another effect the Moon has upon our evolution is that it helps to control the wobble of our axis; this resulted in the seasons stabilising and the weather being similar for long periods so that complex life forms were able to adapt and succeed.

Without the Moon, the ecosystems on Earth would have to endure extreme weather conditions, fluctuating seasons and short days. The co-existence of the Moon and Earth also effects the gravitational pull on the Earth altering its orbit which again would have changed the seasons. Under conditions without the Moon, it is unlikely that complex life forms would have evolved on land. Even if they did succeed, they would have struggled to develop, because shorter days, would allow light for an average of four hours and hence less ‘constructive’ time. If any life had developed in this world of extremes, it would have been restricted to the seas, with only small organisms being able to survive on dry land. Not only has the Moon had a direct effect on the Earth but it has also aided our development by deflecting asteroids from their course towards Earth. The Moon’s gravity often pulls asteroids off their course enough for them to miss the Earth or causes them to in fact crash into the Moon.
Let us say that somehow Man managed to evolve without the Moon.¬†We would not have developed as far in mathematics and¬†science. The Moon was an object of curiosity, being the second largest object in the sky and appearing to disappear and reappear every 28 days whilst changing its shape. The Moon allowed Man to begin to use time and not just watch it pass by. It gave humans a measure of time along with the day that allowed them to chart the repeating pattern of the year. This allowed Man to progress from being gatherers and not much more sophisticated than other apes, to growing crops and altering the environment. Of course, the Moon is not the only thing that changes throughout the course of the year. The length of day and the Sun’s height in the sky also change but these are much more subtle changes.

Man would have struggled to time the length of the day because one cannot look directly at the Sun to tell the time. Hence, the Moon was a much easier way of recording time. Once Man had started using the Moon for recording time, it would have created great curiosity. The cycle of a Moon would not appear to be exact, for it takes 29.5 days to do a complete cycle. For Man this would result in the cycle sometimes appearing to be 29 days and at others 30 days. However, Man would discover a pattern as to the number of days. In order to count the number of days, Man would have had to improvise a way of recording numbers – possibly notches on bone or scratches on a tree. However it happened, it is very likely that our viewing the Moon started the use of numbers and the evolution of mathematics. These calculations would have continued to develop as lunar eclipses occurred when the Moon appeared to suddenly die when it is at its fullest (lunar eclipses only happen at the full Moon) and then be rapidly reborn. Man would have started to predict the next eclipse in order to be ready to offer gifts to the god of the Moon. The first myths and stories of creation revolved around the Sun and the Moon and the gods who dwelled in them. There are even suggestions that Stonehenge was built, not to commemorate the Sun, but the Moon. The Moon initiated the development mathematics and astronomy through the creation of the calendar. Without the Moon, it is feasible to say that Man would still be a hunter-gatherer having been unable to progress onto the agricultural phase of development. For, he would not have been able to judge when to plant in order to have the correct growing conditions.

Once Man had begun to use the Earth for his own will, he began to explore. The Moon’s effect upon the tides, and the subsequent reduction in wind speed, were vital for this to be possible. This exploration allowed the beginning of trade and the development of civilisations. The Moon also became an important implement in navigation, allowing Man to wander further out to sea, as he did not need to cling to the coastline.

The Moon continued to feed Man’s inquisitiveness. Astronomers examining the night sky would have noticed that the majority of the stars remained in the same place in relation to each other, except for five brighter ones, the planets, and they were given the names of gods, which they still have today. The Sun and Moon also shifted position in relation to the stars and hence were considered planets as well. A system of the movement and position of the planets, the Moon, the Sun and the stars developed and was passed down through many civilisations. It was finalised by Claudius Ptolemy and it said that the Earth was the centre of the universe and that it was surrounded by concentric spheres. The nearest held the Moon, then Mercury, then Venus , then the Sun, then Mars, then Jupiter, then Saturn and finally the stars.


The Moon is the only object in the night sky that suggested to the early astronomer that there were other worlds and that the Earth was not the centre of the universe. It is the only section of the Ptolemaic system that caused any doubt as to whether it was correct. This is because the stars by themselves are just dots of light and there is no reason to think otherwise, particularly since they never change position in relation to each other. Why should they not be just a covering and Earth be the only thing in the Universe? The planets did not pose as a problem either as they were still dots of lights they were simply placed in their own spheres that were transparent so that the stars could be seen through them and to the early observer the Earth was still the only world. The Sun was not an anomaly or a problem either for although it was massively larger it was still an object of light. The stars, the planets and the Sun all composed of light whereas the Earth was dark; they all travelled in a circular direction but, on Earth, objects rose or fell and they did not change or decay like the Earth. Aristotle believed the heavens to be made of ‘ether’ and the Earth to be made of fire, air, water and Earth. The heavens were completely separate. Even meteors and comets fitted this pattern of light and dark, heaven and Earth even though they reappeared and disappeared they were still made up of light and thus heavenly.

The Moon is the exception here. It appears to be made of ether yet it changes its shape. Originally, it was believed that a new Moon was born out of the old one. Later on, though, astronomers came to notice that the portion of the Moon that shone was the one facing the Sun. This idea developed when astronomers examined the relationship between the position of the Moon and the Earth and compared it to the Moon’s shape in the sky. It became clear that the Sun shone on half of the Moon and as it changed its position relative to the Sun, so did its shape. The Moon was now considered to reflect the Sun’s light. By the time of the Greek empire it was accepted that the Moon did not disappear but in fact it was just not illuminated by the Sun to strengthening this theory was the fact that sometimes the rest of the Moon could be made out glowing red very faintly.

The Moon was now a world, like the Earth, made of Earth, fire, air and water and it was now seen to be no longer perfect due to the dark patches upon it. Earth was no longer the only possibility of life. The idea of life on the Moon encouraged astronomers to try to understand the heavens. The Greeks managed to calculate the size of the Earth and the distance of the Moon from the Earth, which allowed them to predict the size of it. They calculated it to be over two thousand miles wide, it was definitely now a world. The Greek author, Lucian of Somosata, even wrote a novel involving a trip to the inhabited Moon (2nd century AD).

It is possible that if the Moon had not existed that Man would have still discovered other worlds when the telescope was created for military views. However, they would not have had the same drive to search the heavens for other worlds. Only the Moon was near enough for its size to be calculated by trigonometry. Once the Moon was officially the world, it suggested that there were other worlds. Ideas about the universe did not change hugely until Galileo, in 1609, used the telescope to examine the night sky. Galileo found that the planets were no just mere dots of light but large spheres and Venus was even close enough to have phases; from this, he deduced that they too were worlds. In the 17th Century, authors again began writing about trips to the Moon. Without the Moon, Galileo may still have discovered these unknown worlds and authors may have written about trips to Mars and Venus. These planets, however, are so much further away. Astrological science has developed greatly since Galileo and it is now accepted that the Earth is not the centre of the universe. If the Moon did not exist, Man may have continued to explore space from the surface of the Earth but would he have attempted to send shuttles into space. The Moon is the only object in space that Man could feasibly fly to and it provided a dream. NASA has not yet managed to send a Man to Mars, even given the knowledge acquired during the trip to the Moon. Not only has the Moon affected space travel but throughout the ages it has had an impact on shipping and trade. In the modern world the ebb and flow of the tides is vital for shipping and fishing.

In conclusion, the Moon has done a great deal for civilisation. It has allowed us to evolve by stopping our wobble and creating tides. It then teased our intelligence and thirst for knowledge. Would Man have dared to try to send anything into space, even a satellite, without it? The Moon will not always be with us; in fact, it is moving away from us at a rate of 4cm/year (admittedly that is very slowly). The Moon allowed us to exist; the question now is will it stick around long enough for man to learn either how to live without it on Earth or find another suitable planet for man to inhabit.



1. Books Back to cited text no. 1
2. Does anything eat wasps? by New Scientist Back to cited text no. 2
3. A Short History of Nearly Everything by Bill Bryson Back to cited text no. 3
4. Internet Sites Back to cited text no. 4
5. www.mountainman http://www.mountainman.com.com – The Triple Triumph of the Moon – Isaac Asimov Back to cited text no. 5
6. http://curious.astro.cornell.edu/index.php Back to cited text no. 6

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