Thousands of poems, millions of admirers, an object that lights up the lives of star-crossed lovers, the Moon. Have you ever wondered how this thing of beauty has had a profound impact on our lives? Oh, I am sure that a 4-billion-year-old relationship between our Earth and the Moon would redefine true love. Here is a wonderful story of how two planets that were meant to be, collided with each other and became entangled in the web of love. This collision was one reasons why our Earth transformed from a barren Hell into a paradise beaming with life.
Proto Earth, a barren planet
4.5 billion years ago, proto-Earth, which formed from the remnants of swirling gas and dust, revolved around infant Sun. The planet was a barren hell filled with lava due to the rise of hot magma from the planet’s mantle. The atmosphere comprised harmful gases erupting from volcanos, and there was no protection from asteroids and space debris. Several asteroids and debris hit young proto-Earth as they revolved around the newly formed Sun. For millions of years, our planet, which we now call home, remained lifeless and uninhabitable.
The collision that was meant to be
Around 4.5 to 4.6 billion years ago, a planet named Thea revolved around the young Sun, its orbit nearly along Proto-Earth. It was a planet the size of Mars and travelled at the speed of 4 km/second. Due to the gravitational influence of either Venus or Jupiter, it headed towards a collision with Proto-Earth. Thea struck Earth at a 45-degree angle, at the speed of 8,900 miles per hour. The collision resulted in the ejection of pieces of Proto-Earth and Thea. The Earth’s gravity slowly drew some particles. A huge chunk of rocks began slowly forming into a small planet by accumulating the remnants of the proto-planetary disc that had formed due to the collision. This small planet, the Moon, got tidally locked to the Earth and began revolving around it. This whole process would have taken a hundred million years to happen.
The collision between Thea and Proto-Earth had slightly tilted Earth’s position and stabilized its orbit around the Sun, thereby forming a perfect orbit in the habitable zone of the star. Before the collision, Earth was spinning faster with no probability of a stable atmosphere forming. The collision slowed down the Earth’s rotation and stabilized it further. If Thea had struck Earth head-on, it would have resulted in both planets being destroyed instantly, creating a short-lived asteroid belt between Venus and Mars. In January 2016, there was evidence that confirmed the presence of the same materials, which turned out to be Thea’s remains, found on both the Earth and the Moon.
The formation of the Moon and Alternate hypothesis
Lunar rock samples, retrieved from Apollo astronauts, had a startlingly similar composition to Earth’s crust. This confirms that the formation of the Moon was likely due to a violent event. The Moon’s formation from the resulting collision between Thea and the Earth is known as the Giant-Impact hypothesis, which is widely accepted by scientists today. However, let us look into three other hypotheses that existed from the beginning.
The first hypothesis describes that a single planet body split into Earth and Moon. The second one speculates that the Moon was captured by the Earth’s gravity, which was the case for most outer planets. The third hypothesis describes that the Moon’s origin formed from the remanets of the protoplanetary disk that accreted.
An inseparable bond that binds our life force
The Moon helps the Earth rotate in its axis and keep it in perfect orbit. Although most asteroids that are aimed close to the Earth’s orbit usually get caught by Jupiter’s massive gravity, some smaller asteroids land on the Moon. Without the Moon, there would be no environment for many coastal animals to survive as our oceans would have smaller tides, thereby preventing crabs, starfish, turtles, and snails from reproducing and surviving. The temperatures on Earth could vary erratically as the Earth’s axis would tilt by 45 degrees or more. There could be no tilt that could result in no seasons or a major tilt that could result in extreme seasons, perhaps an eternal ice age.
Without the Moon, the Earth’s rotation could slow down further, resulting in far shorter days and more days in a year. We must always celebrate the inseparable bond between the Moon and our Earth. Their strong relationship helps humans thrive. That fortunate collision has helped the Earth stay in perfect orbit and given birth to the evolution of the life we see today. Many scientists theorize that without the Moon, life on Earth may not have evolved as we know it. This is because the Earth would have had a far different orbit around the Sun, leaving it either too hot or far too cold for life to exist. Thea was a planet that sacrificed itself to give us life. It is this 4-billion-year-old relationship between these two lovebirds that helps us evolve and thrive on this planet.
Space Age 