Gazing at the Crescent Earth?
Astronomers believe that one day we humans will have colonies on the moon. It is especially more likely to happen since the spacecraft Prospector discovered water ice on the lunar surface. For decades science fiction writes have speculated about moon bases, but what would it be like to be a stargazer on the moon?
Most folks have seen pictures from the lunar surface taken by the Apollo astronauts. We know that the moon is a dusty rocky place. What you might not know is that those rocks are quite dark, they look a lot like the dark basaltic rooks of the Earth?s oceans. You probably also know that there is no air to breath and that the surface gravity is only one sixth of what we are used to on Earth. Life would be full of bounces!
Since there is no air on the moon, our lunar stargazer would never need to worry about cloudy skies. There is no weather on the moon since there is no atmosphere. Stars and planets would be visible during the daytime as well as at night. This is also because the moon possesses no atmosphere to scatter the sunlight and produce the blue skies we are so familiar with.
Daytime and nighttime on the moon would each last 354 Earth hours. This would make a lunar day of 29.5 Earth days. This comes out to 13.5 moon days in one Earth year. Clearly, new working ?time periods? would have to be established.
Lunar bases would probably be on the side of the Moon which faces the Earth, so that the inhabitants could view the home planet. Since the moon rotates on its axis in the same period of time as it revolves around the Earth, one side of the moon is always facing the Earth and one side is always turned away from the Earth.
So how will the Earth look from the Moon? A bit strange, the Earth would appear to stay in the same spot in the sky during the long lunar day and night. The stars would move from east to west, just as they do at home, but the Earth would appear fixed in position. Also, the diameter of the Earth would appear four times larger then the full Moon appears in our Earth skies. It would be quite easy to view the Earth?s oceans, land and clouds. If we were to stand in the middle of the moon (as viewed from Earth) our blue planet would appear directly overhead. However if we were standing near the edge of the Moon (again, the ?edge? as seen from Earth) than the Earth would appear low on our lunar horizon, perhaps even obscured by lunar mountains.
Another interesting observation would be that the Earth would appear to go through the phases that we see the Moon go through from Earth. However, the Earth would be in the opposite phase of the Moon as seen from Earth. This means that when a person on Earth sees the Moon as full, at the same time a person on the Moon would see the Earth in total shadow.
The Sun?s motions would appear fairly similar to the lunar dweller, with the main difference being the rate of movement. The Sun would rise in the lunar east, taking two weeks to cross the sky and then to set in the lunar west. Two weeks after that the Sun would again rise in the lunar East.
Perhaps the most interesting place to be would be at the lunar poles. Here, the Earth would appear to ?sit? on the lunar horizon, while the Sun would also move along the horizon, never to set. Dwellers on the side of the Moon facing away from the Earth would never see our home planet, but would forever be facing the void of space.
Copyright © 1999 Kathy Miles and Charles F. Peters II