Scientists have calculated the future considering the fact that the Moon is gradually moving away from Earth, which is also causing our planet to rotate more slowly.
According to Live Science, the Moon’s orbit around Earth appears so regular that some civilizations relied on its movements to track dates. However, modern science reveals that it is slowly drifting away from our planet, causing oceans worldwide to bulge.
Researchers have determined the speed at which the Moon is moving away from Earth by using reflectors that NASA placed on the lunar surface during the Apollo missions.
Earth seen from the Moon – (Photo: Jeremy Horner).
For over 50 years, laser beams from Earth have been directed at these reflectors, with the reflected pulses recorded to help NASA estimate that the Moon is drifting away from Earth at a rate of about 3.8 centimeters per year.
This rate is comparable to the speed at which human nails grow, but the accumulated distance over the vast lifespan of astronomical objects creates a significant issue.
The Earth’s oceans are bulging towards the Moon due to its gravitational influence on tides. Conversely, our “Moon” is gradually taking on an oval shape due to gravitational interactions pulling it from Earth.
Astronomer Madelyn Broome from the University of California, Santa Cruz, states that about 4.5 billion years ago, when the Moon was formed, Earth’s rotation was considerably faster, with a day lasting only about 5 hours.
At that time, the Moon was also much closer to Earth, and the two celestial bodies continually influenced each other. The gravitational force from the Earth’s tidal bulge affected the Moon; conversely, the ocean movements caused by the Moon’s gravity created friction on Earth’s surface, slowing its rotation.
Since Earth and the Moon are part of an interactive gravitational system, the momentum of the entire system must be conserved. Angular momentum represents the energy contained in something that is rotating. The faster it spins and the farther apart the two objects are, the more energy is present, and vice versa.
Thus, as Earth slows down—while in the past, the Moon also slowed down—the two bodies must have balanced the angular momentum of the entire system by moving away from each other. The Moon has taken on that movement.
Today, the Moon no longer slows down because it has long been tidally locked with Earth, meaning it always shows only one face to our planet.
Models suggest that eventually, Earth will “hold on” to the Moon by also becoming tidally locked, facing the Moon with just one side so that the Moon doesn’t have to drift away any further.
This will happen in approximately 50 billion years, according to Dr. Jean Creighton, Director of the Manfred Olson Planetarium at the University of Wisconsin-Milwaukee, and Professor Eric Klumpe from Middle Tennessee State University.
Unfortunately, the parent star of both—our Sun—will exhaust its energy and evolve into a red giant before collapsing into a white dwarf in about 5 billion years.
During its expansion into a red giant, the Sun is expected to engulf several nearby planets—of course, including their satellites.
Earth is on the list to be “swallowed,” according to calculations. This means that both the Moon and Earth will vanish much sooner than they decide to stop spinning together.
