Planet:Earth

The Earth in Spore, is an Easter egg planet. Earth, along with other planets from the real life Solar system, can be found in the game. Once a player finds Earth, they are rewarded the "Manifest Destiny" Achievement. If a player chooses to destroy Earth with the Planet Buster, they will also achieve the "Oh the Humanity!" achievement. Earth is uninhabited by default, but sometimes, creatures can stroll around the planet.

Terrascore
Earth has a Terrascore of 1 (High Atmosphere). Many different interpretations have been formed by players to explain this, ranging from a reference to global warming to a general comment that, despite being the origin of humankind, Earth is not necessarily the best planet to harbor life in the universe.

Other explanations suggest that Spore is set before the age of mankind millions of years in the past, before Earth was ever inhabited by humans, which may involve the theory that aliens visted Earth millions of years ago. By the Space stage it is about 2 billion years.

Another answer is that humans are extinct on Earth or left due to inhospitable conditions, placing the game's setting in the future. The "Earth in the future" theory can be backed up by the fact that in the history timeline it shows how long you've been in the Spore galaxy. This would explain the modern continental positions. Finally, Earth could be just a random planet called Earth and a star called Sol, or that the game is set in a different universe where the Earth is in the condition it is in in-game.