The Fate of Earth's Moon: Will it Ever Disappear?

The moon is slowly drifting away from Earth at a rate of about 1.5 inches per year due to the gravitational effects of each on the other. Tidal forces are also slowing the rate at which the moon rotates on its axis, resulting in the moon "tidally locking" with Earth. In about 50 billion years, Earth's slowing rotation would make it tidally lock with the moon so that Earth would permanently show just one side to the moon. However, in about 5 billion years, as the sun begins to die, it will swell to become a red giant star, "at which point the Earth-moon system will almost certainly be disrupted and destroyed."