Every year, the Moon drifts about 1.5 inches (3.8 centimeters) farther from Earth. Scientists have measured this with remarkable precision by bouncing lasers off mirrors left on the lunar surface by astronauts and probes, tracking the time it takes for light to travel to the Moon and back.

While this might sound insignificant compared to the Moon's average distance of 239,000 miles (384,000 kilometers), it reveals fascinating insights about the forces shaping our planet and its natural satellite.

The reason the Moon is slowly drifting away comes down to tidal forces. The Moon's gravity pulls more strongly on the side of Earth closest to it and more weakly on the far side, creating tidal bulges in the oceans.

Because Earth rotates faster than the Moon orbits, these bulges don't line up perfectly with the Moon. Instead, they lead slightly ahead, dragged forward by Earth's spin. The gravitational pull from these misaligned bulges gives the Moon a small but steady forward tug in its orbit.

This forward pull acts like a slingshot, increasing the Moon's orbital momentum and pushing it farther away from Earth over time.

As the Moon gains momentum, Earth loses some of its own. The energy driving the Moon outward comes from Earth's rotation, which means our planet's spin gradually slows down. As a result, days on Earth are slowly getting longer -- by just a fraction of a second over millions of years.

For now, the effect is negligible. We will continue to have tides, eclipses, and 24-hour days for many millions of years.

Yes. The Moon formed about 4.5 billion years ago after a Mars-sized object collided with the young Earth, ejecting material that eventually coalesced into our satellite. At that time, the Moon was much closer, appearing dramatically larger in the sky.

Evidence from fossilized clams shows that 70 million years ago, Earth's days were only 23.5 hours long. This matches predictions from astronomical models showing the Moon's gradual retreat and Earth's slowing rotation.

In theory, the process could eventually lead to Earth becoming tidally locked with the Moon. This would mean Earth's rotation period would match the Moon's orbital period, leaving one hemisphere permanently facing the Moon. At that point, the Moon would stop drifting away.

But this scenario is unlikely to play out. In about a billion years, the Sun's growing brightness will boil away Earth's oceans, eliminating the tidal bulges that drive the Moon outward. A few billion years later, the Sun will expand into a red giant, likely engulfing or destroying both Earth and the Moon.

For now, the Earth-Moon system remains in a delicate dance. The Moon's slow retreat is a reminder of the invisible forces at work every day, shaping tides, slowing Earth's spin, and writing the story of our planet's past and future.

Until the far-off future, we can keep enjoying ocean tides, solar eclipses, and the quiet presence of the Moon above.