Will Earth Ever Lose Its Moon?


| LAST UPDATE 04/23/2023

By Daria Appleby
Moon Pulling Away From Earth
Bettmann / Contributor via Getty Images

As the sun goes down at dusk, we are naturally conditioned to expect to see the moon shine in the sky. However, recent discoveries, according to Live Science, have proposed theories that the moon is "slowly creeping away from Earth." Due to its regular rotation, it's hard to imagine this, but now Nasa has determined new rates after 50 years of research.

In the past 50 years, Nasa has been experimenting with the moon's rotation rate carefully. Using their reflective panels, the advanced technology has allowed the team of scientists to measure accurately certain aspects of the moon's relationship with Earth. These researchers have fired laser beams from Earth at the mirrors - reflective panels - "to detect pulses." Results showed an estimate "that the moon is straying away from Earth by about 1.5 inches (3.8 centimeters) per year." They found due to the "gravitational effects" the Earth and the moon have on each other, the chances of the moon pulling away from the Earth through forces are more likely than expected. According to Madelyn Broome, an astrophysicist at the University of California, the gravitational pull is constantly creating friction, thus, "slowing the planet's rotation."

Moon Pulling Away From Earth
NASA via Getty Images
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Broome continued to explain, "Since the Earth and the moon are part of the same gravitationally interacting system, total angular momentum must be conserved — stay the same — between the two... Angular momentum describes the energy contained by something that is spinning. The faster you spin, the more angular momentum you have. The slower you spin, the less." However, she further added to her point, "it's not just the rate of spinning that affects angular momentum... How far you are from the center of the system also matters. Further means the angular momentum of the system goes up. Closer means your angular momentum goes down. On the other hand, according to the University of Arizona, "the moon likely formed from debris that resulted from a crash between the nascent Earth and a Mars-size object," hence, these specific tidal forces enforced the gravitational pull that has been creeping up slowly but surely. With that in mind, scientists predict in around 5 billion years, the sun will eventually become one giant red star, and in around 50 billion years, the Earth's slow rotation will cause it only to show one side of the moon permanently.

While these discoveries might come across as alarming, NASA scientists have ensured the moon is not entirely leaving us any time soon. Regardless, the moon is constantly moving, and so it should be. However, its orbital rate is slowly but surely slowing down, forcing itself away from Earth's surface.

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