Players who want to control/terraform Earth Players who like Easter eggs
In the Spore universe, the planet Earth is an Easter egg. 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.
Earth has a Terrascore of 1 (High Atmosphere). This makes sense because T1 means 1 Earth. Strangely though, Earth turns a brown-red color when it reaches a terrascore of T3. 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. A common explanation also suggests that Spore is based before the age of mankind, millions of years in the past, before Earth fully became a habitable planet, which may involve the theory that aliens visted Earth millions of years ago. By the Space stage it is about 2 billion years. A far more likely answer is that humans are extinct on earth or left due to inhospitable conditions. The Earth in the future can also 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. Other reasons are that Earth could be just a random planet called Earth and a star called Sol, or even that the game is set in a universe where the Earth is in the condition it is in in-game. The most respectable reason that they did this is just to make Earths features more visible, with less plants blocking your view. However, since no confirmation on these views has been provided by the game creators, the possibility that this was simply a developer's oversight remains. The proportions of Earth are surprisingly small, with many small countries such as the UK or Ireland are shown as being the size of an average spaceship, however this is due to the game's processor and engine, it should also be noted that Earth is the same size as other terrestrial planets in Spore.
In addition, when the atmosphere is increased to make Earth T0, many of Earth's continents (including South America, parts of North America, much of Europe, and Australia) become flooded, again prompting some players to cite this as a reference to global warming. The only way to make Earth T3 without flooding it is to use the Staff of Life, necessary if the player wishes Earth to remain the same.
If you want to colonize the planet, it seems like the only locations to build a colony without mutilating the terrain too much is Northern Asia or Antarctica, although there have been reports of very low or no terrain manipulation if placed in Africa or America from some gamers. Earth is usually a yellow spice planet, but can have green, pink or purple spice in some cases.
It is suggested that before you depart your home system, to buy lots of Bio-Protectors, Bio-Stablizers, and Uber turrets in case you want to colonize all of Sol and have high security. Make sure to ally with or destroy any other empires near Sol so they don't attack.
For some reason, you aren't allowed to place a monolith on Earth. However, occasionally a tribal species develops there, like on any other planet. It is not yet known if they can develop further, as cities and colonies would severely distort the landscape.
If you make it to the Galactic Core, Steve will give you the Staff of Life. He also mentions the "third rock from Sol," also known as Earth. Though he mentions a "free breakfast and presentation," if you do go to Earth there will be nothing new there; however, this does indicate that Steve may have originated from Earth, and is an example of humans in future times or it may just be a joke from Maxis.
Due to Earth changing color when T-3, some players may not want to terraform, but this can be countered with planet coloring tools.
It is possible to create a new human race by using the Create Creature and Monolith, however they may drastically change the terrain with their cities as they reach civilization stage.
While on the Earth, planets seen as faint star-like twinkles are seen in plain sight, many times magnified. Jupiter appears in the sky orders of magnitude bigger than in real life.
Since it is for some reason uninhabited, this may be Earth in the future after some sort of massive-scale disaster, such as a nuclear war, that wiped out humanity or forced them to leave the planet, likely the latter due to Steve being a probable former resident of Earth.
In some games, Earth may glitch up, and turn into a round ball upon entering the planetary view.
For some reason, Britain appears to be connected with Europe. This is most notable with the Hologram Scout. However, this may vary as Earth varies slightly between games.
The Grox could be super-advanced humans millions of years in the future. This theory would revolve around humans being able to escape Earth before its ecosystem deteriorated, however. This would ultimately mean that The Grox originated from Earth, but is a planet cast aside, as it is no longer needed by The Grox due to its T1 atmosphere. The Grox may have decided that since it's far away from the Galactic Core, that it's not worth inhabiting once more.