Liberated in Outer Space
As you may know space is a vacuum (an area where pressure is so low that the particles in that area do not affect any of the pre-existing processes underway in that specific area), and not the kind you use when doing your chores. When you think of geography on earth you picture a set of features that include valleys, which is similar to what the geography of space is like, except the valleys in outer space are invisible to the naked human eye, since the valleys in space are caused by gravity.
Most objects in outer space have magnetospheres which cause them to pull in smaller objects around them; however when a large object begins to pull in another very large object a Lagrangian Libration Points are born!
Lagrangian-Libration points were first discovered and named after Joseph-Louis Lagrange who was an 18th century mathematician and physicist. They were first mentioned in his paper titled “Three Body Problem” that he published in 1772.
As described by many astrophysicists Lagrangian Libration Points are areas in space between large bodies of matter where the combined gravitational forces of the the two bodies is equal to the centrifugal force (an apparent force that acts outward on a body moving around a center, arising from the body's inertia) felt by a smaller third body. They are also considered the “parking spots” of space since when an object like a spacecraft is present at these points, it is not pulled in by either of the large bodies that surround it.
Figure 1 below is a diagram of the Lagrangian-Libration Points between the Earth and the moon. As you can see there is a small dot in the center top portion of the figure which represents and is labeled the Moon, and there is a dot labeled Earth and encircled within a geosynchronous orbit (an orbit high above the Earth that satellites use to match the Earth’s rotation ie. The Hubble Telescope). There are also five points labeled beginning with the letter “L” (L1, L2, L3, L4, and L5) that represent the Lagrangian-Libration Points. The Points L1, L2, and L3 are saddle shaped valleys, so if an object is displaced perpendicularly to the Earth-Moon axis it would slide back to the Earth-Moon axis. If the object is displaced along the axis it moves away from the L1, L2, and L3 points indefinitely, which is why they are called the Unstable Points of Equilibrium. The points L4 and L5 are bowl-shaped valleys so any object displaced in any direction will return back towards the Libration Point, which is why they are called the Points of Stable Equilibrium.
So the next time you stare up at the dark night sky, just remember you might as well be looking at what on Earth would be considered a beautiful valley.
Earth-Moon Liberation Points
Picture Source: National Space Society
