On July 20, 1969, the world sat in anticipation around radios and TV screens when Neil Armstrong became the first man to set foot on the moon. The Apollo 11 launch stood as an American triumph in the legacy of human fascination with the moon and stars. Recent Chinese explorations of the dark side of the moon show that we are still preoccupied with the mysteries and secrets of Earth’s first cousin. There are many surprising facts about the moon, some well-known and others less so.
Birth of the Moon
Measures of lunar rocks show that the moon is roughly the same age as the earth, but these measures are taken on the scale of billions of years where a few hundred thousand is the blink of an eye. The leading theory regarding the formation of the moon is that it was created in the wake of a collision between young Earth and a large foreign body, causing debris from the impact to float into space.
The moon has a thin atmosphere incapable of shielding it from cosmic rays and colliding objects. Because of this, the planet is regularly bombarded with asteroids and comets that have led to the many craters on its surface and a thin layer of space dust coating the entire surface of the moon. The dark areas are impact sites known as maria, derived from the Latin word “mare” meaning sea. The lighter areas are called highlands. While the moon has no naturally occurring water sources, there are deposits of frozen water from comets and meteoroids around the poles of the moon.
Humans have long been fascinated with the moon’s ability to influence the tides and climate. These curiosities have been embodied from early astronomy to modern agriculture. Medieval societies believed that lunar cycles influenced behaviors to the point of inducing madness in some individuals. This is why the prefix “luna” in lunatic is the Latin word for moon. That the moon could induce madness was such a strong belief that it was once included in English law. While we no longer believe this, modern studies do show that lunar cycles can influence human sleep patterns.
Dark Side of the Moon
The moon completes one complete rotation around its own axis during the same period of time (27.3 days) that it takes to orbit the earth once. This is why the moon always shows the same face to the earth. The most recent explorations have been to the opposite side, known as the “dark side of the moon.” In actuality, both sides of the moon experience two weeks of sunlight and two weeks of darkness. Because of this, the “dark side” is more accurately known as the “far side of the moon.”
Adrift in Space
The Earth’s gravitational field is responsible for both the formation of the moon and its stable orbit around Earth. However, Earth is not a perfect sphere and exerts non-uniform gravitational pull on the moon. This phenomenon is responsible for the shift in tides as a result of lunar cycles, and it’s also causing the moon to expand its orbit ever so slightly. Each year, the moon drifts roughly 4cm away from the earth. After 500 million years, this slight drift will place the moon about 14,600 miles away from Earth.