Perigean spring tide Perigean spring tide A proxigean spring tide (also known as a perigean spring tide) is a tide that occurs three or four times per year when the Moon's perigee (its closest point to Earth during its 29.5-day elliptical orbit) coincides with a spring tide (when the Earth, Sun and Moon are nearly aligned every two weeks). This tide usually adds only a couple of inches to normal spring tides. The Moon's orbit around Earth is elliptical, which causes the Moon to be closer to Earth and farther away at different times. The Moon and the Sun are aligned every two
Earth 2150: The Moon Project Earth 2150: The Moon Project Earth 2150: The Moon Project is a sequel to the real time strategy game "Earth 2150". While the game is in fact a stand-alone game, many consider it an expansion pack because it does little more than provide new missions, and weapons. The story takes place alongside the original game's story. "The Moon Project" was released in 2000 by Strategic Simulations, Inc. Earth's final war is in full swing. The United Civilized States, Eurasian Dynasty, and the Lunar Corporation fight over what is left of the world’s resources in order to escape the blue planet