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THE POINTS OF LAGRANGE OR LAGRANGE POINTS SOMEWHAT LESS THAN A DOZEN

Gravity warps space time and objects travel on straight lines that follow the distortions of space and time. It took Einstein to figure that out. A good way to visualize our solar system is to think of a surface with the planets and the Sun in deep wells in that surface. The Sun's gravity well is the deepest because it is the most massive. The well is deepest at the Sun's surface and the slope of the depression continues to the farthest reaches of the solar system. An interesting thing happens when you have two objects with mass distorting the surface of space time. Joseph Lagrange figured out, in 1772 no less, that there are several points in a two body system where the the gravity or distortion of the surface of space time from both masses will be equeal. These points turn out to be very important because if you put something at one of these points it will tend to stay there. The lagrange points are labeled L1 - L5, and I will use the Earth Moon system to illustrate. L1 is located between the Earth and the Moon, closer to the Moon because of the greater mass of the Earth. L2 is located beyond the Moon at about the same distance. L3 is located in an odd position on the other side of the Earth from the Moon and is not too significant. ( Although there have been several Sci Fi movies made about a twin planet of Earth located at the Earth Sun L3 point, none of them very good though, and probes have found no planet at that location. ) The best defined, most useful, and easiest to access Lagrange points are L4 and L5. These are located on the orbital path of the Moon around the Earth a little bit ahead and behind the Moon itself. The L4 and L5 points are larger and more stable than the other Lagrange points and all sorts of space debris naturally gathers there. The planet Jupiter has collected groups of asteroids at it's L4 and L5 points which are called the Trojan asteroids. The L4 and L5 points of the Earth Moon system have been candidates for space colony locations for many years. In 1978 an Explorer satellite was placed to orbit the Earth Sun L1 point to provide early warning of Solar particle events. Recently NASA has proposed a new Earth Sun L1 satellite and strangely is promoting it as a momentous new idea even though it is twenty years old.