Moon's relationship to Planet Earth (Space dot-com posting)

excerpt from longer posting at www.space.com/ (Space and NASA News) Orbit/Earth Relationship Tidal effects The moon's gravity pulls at the Earth, causing predictable rises and falls in sea levels known as tides. To a much smaller extent, tides also occur in lakes, the atmosphere, and within the Earth's crust. High tides are when water bulges upward, and low tides are when water drops down. High tide results on the side of the Earth nearest the moon due to gravity, and it also happens on the side farthest from the moon due to the inertia of water. Low tides occur between these two humps. The pull of the moon is also slowing the Earth's rotation, an effect known as tidal braking that increases the length of our day by 2.3 milliseconds per century. The energy that Earth loses is picked up by the moon, increasing its distance from the Earth, which means the moon gets farther away by 3.8 centimeters annually. The moon's gravitational pull might have been key to making Earth a livable planet by moderating the degree of wobble in Earth's axial tilt, which led to a relatively stable climate over billions of years where life could flourish. Eclipses During eclipses, the moon, Earth and sun are in a straight line, or nearly so. A lunar eclipse takes place when Earth gets directly or almost directly between the sun and the moon, and Earth's shadow falls on the moon. A lunar eclipse can occur only during a full moon. A solar eclipse occurs when the moon gets directly or nearly directly between the sun and Earth, and the moon's shadow falls on us. A solar eclipse can occur only during a new moon.