Introduction to the Universal Century Ⅰ Part 2
The Arrival of the Space Emigration Age

U.C.0001 (Universal Century Triple-0h-One), the first year of this era, also marked the start of space emigration.

Previous to this, the “Earth Sphere” concept was introduced.
This is humanity’s living area, comprised of Earth, the Moon, and the space colonies.

In the Earth Sphere, there are five points where the gravity of Earth and Moon are in balanced equilibrium. As the Moon revolves around Earth, these points of gravitational equilibrium move in synch with the Moon, and so they always appear to maintain the same direction and distance relative to both Earth and Moon.

These are known as the Lagrange points of the Earth-Moon system, and the space colonies of the Universal Century were placed in special orbits around these points.

Each Lagrange point has its own assigned number. If one were to draw a straight line connecting Earth and the Moon, then L1 would be on the Earthward side of the Moon, and L2 would be on the far side of the Moon, opposite Earth. L3 lies 180 degrees around the Moon’s orbital path, on the other side of Earth.

These three points were discovered by Leonhard Euler around 1760 A.D., and are referred to as Euler’s straight-line solution to the three-body problem.

In addition, in 1772 A.D., Joseph-Louis Lagrange discovered two more points of equilibrium. These points lie along the Moon’s orbital path, at the vertexes of equilateral triangles whose bases are the line connecting Earth and Moon. L4 lies 60 degrees ahead of the Moon in its orbital path, and L5 lies 60 degrees behind it.

In 1969 A.D., Gerard K. O’Neill proposed the idea that a new world of space colonies could be built at the points indicated by Lagrange’s solution.
O’Neill was living through the 1960s and 1970s, when the world population was explosively increasing from 3 billion to 4 billion people. O’Neill’s space colony concept was one of the solutions proposed to humanity to deal with the imminent population explosion.

Later in time, it was said that the world population had passed 10 billion by the last days of the Anno Domini era.

Humanity decided to build space colonies and carry out a space emigration program in order to resolve Earth’s population problem.
This project was widely seen as a desperate recovery strategy to address humanity’s most urgent concerns, such as energy and food problems, environmental issues, and international conflicts.
The winds of a turbulent time led to a movement of perhaps unprecedented scale, as people chose to form a giant governmental system to drive this huge project.
An Earth Federation was established, capable of unifying all of Earth’s nations, races, and regions.

The Earth Federation was created as history’s greatest national organization, in order to combine Earth, the Moon, and the new world of space colonies into the new concept of an Earth Sphere, and govern them as a single unit.
Its governing institution was a Federation Assembly placed above every nation, race, and region, which employed its great political strength to carry out space colony construction and space emigration policies.

Colony Public Corporation slogans such as “You too can live a dream life in the new world” inspired people to apply for emigration, and entire families and regions began applying. With one-way tickets in hand, people began departing for every colony.
However, there were also some who stayed on Earth. The powerful classes who enjoyed ample vested interests would not depart for space so easily, nor would their associates.
By the U.C. 0050s, the suspicion that the space emigrants were “abandoned people” had become a public view in many of the Sides.

Of the Lagrange points, L4 and L5 are gravitational valleys capable of attracting nearby objects such as asteroids. When objects attempt to move away from these points of equilibrium, their courses are deflected by Coriolis forces, and they take up stable orbits around L4 or L5, following a course shaped like a kidney bean.

The space colony clusters known as Side 2, or “Hatte,” and Side 6, or “Riah,” were constructed in stable orbits around L4. Similarly, Side 1, or “Zahn,” and Side 4, or “Moore,” are in stable orbits around L5.

Meanwhile, L1, L2, and L3, which correspond to Euler’s straight-line solution, are more like mountaintops in gravitational terms. When an object begins moving away from one of these unstable points, it will get steadily further and further away. However, there are semi-stable orbits known as halo orbits which circle these Lagrange points, moving in planes perpendicular to the straight line between Earth and Moon.

Historically, the name “halo orbit” was originally given to an orbit around L1. This is because, looking at the Moon from Earth, the orbit appeared to trace a halo around the Moon.

The space colony cluster known as Side 5, or “Loum,” was constructed in a halo orbit around L1. Side 3, or “Munzo,” is in a halo orbit around L2.

In particular, Side 3, or Munzo, would later become the Principality of Zeon and launch a war of independence against the Federation.
It could be that Munzo’s backwater location on the far side of the Moon, which created a sense of situational anxiety, was one of the factors which inspired a warlike state of mind among its citizens.

In U.C. 0079, the Federation Forces developed their first mobile suit, the Gundam, at Side 7, located at L3.
It had been almost 80 years since the start of space emigration.
It may have been a twist of fate that the incident that would determine the course of the space war between Federation and Zeon took place at Side 7, the very last colony cluster to be created.