Every planet has a history to tell.
"Heaven of Order" AKA "New Earth"
This planet was the capital planet of Andromeda union, and it was the only natural terran planet in the Andromeda cluster. Much alike Earth, it had a sun. However, unlike the solar system, the planet was the first planet from its sun.
During terrafroming progress in order to iron out few issues before humans would settle down, every effort was put so that the planet would resemble Earth in every possible way.
It was successful in majority of aspects, and the planet was originally codenamed "Heaven of Order", and later renamed "New Earth" in year 9652 by Andromeda union lower council with 67% of approval.
There was, however, no ocean, on New Earth. Instead, there were large, sea-like, fresh water lakes.
Planet Saturn was originally classified as a gas planet. Therefore, it was deemed not colonizable at first.
However, further thorough on site research revealed that the planet's core was about the same size of Earth with acceptable gravity of 0.8. If gas and liquid were removed, the core could be classified as a barren planet and, therefore, colonizable.
Mars terraforming project was launched on the very same year, actually on the very same day, as Venus terraforming project. Unlike Venus, terraforming fleet did not experience major technical failures in the beginning and full terrafomation was completed far before year of 4112 (Which was when full Venus terrafomation was completed.)
Two Clusters: Earth
1. In General
Earth in Two Clusters is considered "home to all mankind spiritually". However, the reality differs from the ideology.
The Bau was so dominant on Earth for more than 5,000 years that the clan considered the planet theirs and, therefore, enfored harsh entry fee when foreginers would enter the planet. Furthermore, background screen had to be done.
In the end, for almost all people who lived elsewhere, visiting Earth was a distant, if not impossible, dream.
As of year 9599, Earth's popluation is just 1 billion; The Bau expelled 5 billion to Moon.
Earth is the political center of United Sol and the Ark in Washington DC is the heart of the federation.