The distance between the Moon and the Earth is widening. That’s because the moon is slowly drifting away. The shocking discovery comes after centuries of believing that nothing could take them further apart. We were wrong. But what could be the cause of this movement, and what implications could it have for the Earth?
The moon has always been the largest object in our night sky. Aside from delivering night light from the sun, the moon is the reason the Earth remains habitable. Without the moon’s gravitational pull on the Earth, the Earth will vibrate aggressively as it rotates, causing more unbearable weather conditions and natural disasters.
The moon also influences tides, producing predictable occurrences that have formed guides for humans. But this gravitational pull is declining. That’s because the moon isn’t as close to the Earth as it used to be.
It was Edmond Halley, a reputable scientist who lived over 300 years ago who first noticed something. He did so after probing the records of early eclipses.
This suspicion gained more substance after scientists on the Apollo missions placed reflective panels on the moon’s surface. In 1969, these reflective panels and other investigative endeavors not only found that the moon was moving away but discovered the annual rate of this drift.
Every year, the moon retreats from us by 3.8 centimeters. The reason? Tidal forces between the moon and the earth. In other words, tidal friction in the oceans.
Researchers from two reputable universities, the University of Geneva and the University of Utrecht, have studied the moon’s history. They have discovered with the help of computer simulation that at one time, the moon was as close as 22,500km to the earth. Now, this distance has increased to 384,400km.
This lunar recession has its implications. First, the moon’s retreat lowers its gravitational influence on the Earth and causes the Earth’s rotational speed to decrease. As the earth’s rotational speed reduces, days will become longer. Scientists have recorded that in 200 million years, we will have 25-hour days.
Also, ocean tides are not as aggressive as they used to be. This fall in tidal intensity is bad news not only for human marine activities but for the marine ecosystem. Weather changes will also take place. We should expect colder winters and hotter summers as the moon moves away from the Earth.
The lunar recession may also get to a point where solar eclipses will no longer be possible. This will be a major change in the history of the moon since its formation some billion years ago.
The most worrying concern about the moon’s steady shift is its continuous presence within the Earth’s gravitational field. Will the moon drift off till it slips away from the Earth’s gravitational influence?
Thankfully, the answer is no. The moon will stop its movement when it reaches an equilibrium. Then, we won’t have to worry about any further shifts or the loss of the earth’s only satellite.