Near-Earth object focused on asteroids and short-period comets. CNEOS even restricts its definition of NECs to short-period comets—, 107 such objects have been discovered. , only 20 comets have been observed to pass within of Earth, including 10 which are or have been short-period comets. Two of these comets, Halley's Comet and 73P/Schwassmann–Wachmann, have been observed during multiple close approaches. The closest observed approach was 0.0151 AU (5.88 LD) for Lexell's Comet on July 1, 1770. After an orbit change due to a close approach of Jupiter in 1779, this object is no longer a NEC. The closest approach ever observed for
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