Our Moon: The Fellow in the Grass.

We have observed the moon so frequently up the ladder that we hardly think of it any longer. It comes, it comes, it passes its stages like clockwork. However, just sit down and wait a little and you begin to notice how truly weird and fascinating our nearest celestial neighbor is.

An average distant of the moon is approximately 238,855 miles to Earth, which is not very far, and it took Apollo astronauts only three days to get there. It was created approximately 4.5 billion years ago, not much older than the earth itself, and the dominant scientific theory is thrilling: some Mars-sized object named Theia collided with the early Earth, and the debris of that terrible crash finally combined to form a moon as we know it. That is not mythology; the chemistry of lunar rocks strongly indicates that.

The size of the moon compared to that of the earth is one of the least valued aspects of the moon. Our moon is exceptionally large in comparison with its host planet. The majority of moons in the solar system are minute in relation to the worlds which they orbit. We have one that is one quarter the size of the Earth. There are even scientists who call the Earth-moon system a double planet, and that gives a new twist to the way you consider the place we dwell.

It does matter that size even more than you may think. The gravitational force of the moon makes the Earth maintain a constant axial tilt, approximately at 23.5 degrees on a very long time scale. In the absence of the moon, the tilt of the earth might go out of control and this would lead to climate changes so severe that they would remake the life on earth. The moon is not only pretty. In actual sense, it has been a protector of the habitable environment of Earth.

Then there are the tides. The gravitational attraction of the moon on the oceans of the earth forms the tidal waves that have shaped the coastline, affected the marine life and the sailors over the millennia. The sun contributes, however, the moon is the main driver. As the moon, the earth and the sun are aligned, you have the higher spring tides. The lowerly neap tides come when they combine to make a right angle.

Old violence is the record of the surface of the moon. The dark spots that are visible on the Earth are huge plains of solid lava known as maria, which were formed billions of years ago due to volcanic eruptions. The other craters that dot the rest of the surface are impact craters some of which are billions of years old. Since the moon does not have an atmosphere and has little or no geological activity, nothing washes away these features. The moon carries with it its history.

The moon has water ice, as well, which occupies permanently shady craters at the poles where the sunlight never reaches them. This is a discovery that has been verified in the past few decades and has transformed the way scientists and space agencies consider future human endeavors on the moon. Ice would in theory be drinkable, or even rocket fuel.

We have managed to launch 12 human beings to the surface of the moon all between 1969 and 1972. No one has come back since. That is one of the more inexplicable facts in the history of human exploration, and as multiple agencies currently implement efforts to achieve a return, it might not be long.