Earth is the planet from which human beings originated and lived. It is currently the home to the human population and the Scub Coral. The humans left the planet some time after the arrival of the Scub Coral, and after spending seven millenniums in outer space, the humans returned to Earth unknowingly. However, almost everyone is unaware that they are now living on Earth, due to how much it has changed from the Scub Coral merging with it.
10,000 years ago, the Scub Coral crashed into the Earth's atmosphere sometime in the 21st century and landed in the Pacific Ocean. The Scub Coral began to fuse with the Earth's corals and sea creatures in order seek communication with the humans. However, they failed to understand that they were causing panic and fear among the human population after growing to enormous sizes. The Scub Coral also began to fuse with humans who attempted to destroy them. Eventually, out of desperation and fear for their safety, they built huge space ships and left the planet to find a new place to live.
During the absence of the humans, the Earth had changed; the Scub Coral had completely merged with everything on it and the remaining lifeforms in order to fill in their loneliness. This fusing made the Scub Coral bigger than the planet itself, encasing the original Earth underneath of the mass of Scub Corals. Sometime 3000 years before the series begins, an event happens on the Earth that causes the Scub Coral to awaken and experience the Limit of Questions for the first time. The Scubs force themselves back into hibernation, but not without leaving a mark on the planet, which would later be known as the Great Wall as the laws of physics no longer apply in this area that the Scubs awakened in.
After spending 7,000 years in space, the humans returned to Earth. However, due to how much the planet had changed, they never realized that this was their original home planet, as the whole surface was covered in Scub Coral. They rebuilt the planet into the way Earth had been before they abandoned it, and named the planet "Land of the Kanon", due to it lacking countries and oceans. Some time before the Eureka Seven series began, some humans finally discovered that this planet was their original home planet. Decided amongst the Sage Council, the ruling body of the world, this information would not be released because of the huge size of the current human population would prevent them all from returning to their ships they arrived on. Dewey Novak eventually releases this information to the public, before his attack on the Scub Coral Control Cluster to gain favor amongst the populace and hate towards the Scub Coral.
After getting over the Great Wall in order to reach the promised land, Renton and Eureka discover that the promised land is actually Earth, and they realize that the human population has been living on Earth the whole time without knowing it. After Renton saves Eureka from becoming the next Control Cluster, the Nirvash typeZERO departed with half of the Scub Coral in order to prevent the Limit of Questions from happening again. As a result, more of Earth's original surface is revealed when some of the Scub Coral leaves. By the end of the series, more of Earth's surface, including the Pacific Ocean and Japan, are clearly seen. Also, a green ring of coral encirles the Earth and the moon has a heart embedded with Renton and Eureka's names on it.