Turanga's formation is a mystery to many scientists within the Confederacy. As it's the only planet in its star system, its formation is highly unusual. Many speculate that it's either a rogue planet that wandered into the system or it did indeed form from the little dust and rock that orbited Kepler 452. The latter is the more likely as the planet has a complex ring system.
The planet formed an atmosphere and some of the ice chunks within the planet's rings must have fallen to the surface to form the small seas. Its discovery was announced by NASA on 23 July 2015 and was quickly made an object of interest due to it being the first rocky world to orbit within the habitable zone of a sunlike star. However, humans weren't able to explore it fully until the turn of the 4th millenium.
Turanga was first visited by interstellar probes in 2834, cataloged and studied thoroughly and placed on a list of potential worlds fit for colonization, but due to the conflicts within human space, exploration wasn't forefront on the URSS's agenda. When the wars were over and the Confederacy was formed, an explosion of exploration started, and one of the first worlds to be colonized was Turanga. The colonists named her after a famous character from ancient Earth television program Futurama.
The first colonists settled near the New Tethys Sea in the planet's northern hemisphere on July 23, 3012. They built a massive domed city called Leela and began to explore the planet extensively for any form of life. When none was found, the colonists applied to have their planet considered for terraforming. However, lack of nearby ice asteroids and comets to use to raise the world's ocean levels caused their claims to be rejected.
However, the dwindling company Terragen answered their pleas and began to haul in materials from nearby star systems. The company saw this as a way to come back into the spotlight.
Terraforming began in 3101 when the company began skimming ice asteroids across the planet's atmosphere. This caused the water content of the atmosphere to increase. Massive rainstorms formed and began to fill in many of the lower level land masses. While this was happening, the company began scrubbing the atmosphere of all toxic gases and replacing it with Nitrogen and Oxygen along with trace gasses.
The rainstorms lasted for almost twenty years, filling in more oceans. Terragen excavated massive amounts of salt from Turanga's surface and spread them across the planet's oceans. When the rainstorms finally ended, new oceans had been formed.
The next step was for the introduction of larger forms of life, plants and animals. This took another hundred years but in 3233 the terraforming of Turanga was complete. The city of Leela's original location had since been sunk and the colonists had constructed a larger city called New Leela, which became the planet's capital city. The colonists spread from New Leela and formed new settlements and cities.
The current population of Turanga is just over 6 billion.