Earth (StH)

Earth (地, chi?), also referred to as Mobius or Mobius Prime due to its place in the multiverse, is the main setting of the Sonic the Hedgehog universe where all humans and Mobians live in harmony together.

Overview
The dominant species of Earth are humans, which peacefully coexist with animals, plants, and Mobians. The planet also consists of many different deities, such as Chaos, Solaris, and Dark and Light Gaia.

Although there are many countries on the planet, most important events tend to take place in the United Federation. Its capital, Central City, contains the White House, which is where the President of the country lives. Its main military is GUN, which is shown to be a brutal "shoot now, ask questions later" organization that strives for justice but is often clouded in judgement. Some of the planet's larger cities seem to be very advanced and futuristic, as robots and breakthrough technology are commonplace especially to GUN, who create weapons, robots, and air fleets primarily to combat the notorious Doctor Eggman. Cutting-edge cities like Grand Metropolis, Metal City, and Monopole hold robots, flying cars, Extreme Gear, and transport tubes. However, there are vast portions of nature preserved from the clutches of technology, something that Doctor Eggman often seeks to corrupt.

History
The Earth was created by Dark and Light Gaia. Following a constant cycle, Dark Gaia awakens once every million years to destroy Earth and Light Gaia then restores it in an event known as the time of awakening. The two of them would then return to sleep in Earth's core until they can reawaken to continue the cycle.

Over 4,000 years prior to the present day, there were two warring civilizations of Echidnas known as the Knuckles Clan and Nocturnus Clan. In order to overcome their foes, Pachacamac, the leader of the Knuckles Clan, attempted to steal the seven Chaos Emeralds and the Master Emerald from the Chao. However, his civilization was almost completely wiped out by their guardian, Chaos, in the process after he transformed into a terrible monster.

In that same time, a series of sentient weapons, the Gizoids, were created by the Nocturnus Clan, one of which was thought to have destroyed the "Fourth Great Civilization". In actuality, this Great Civilization was the tribe themselves, and they were all really pulled into a pocket dimension known as the Twilight Cage after conquering nearly all of the ancient world.

The alien Black Doom of the Black Arms seemed to have been observing the planet for aeons, as he had warped Glyphic Canyon to it over 2,000 years ago. His people's home, the Black Comet, passed by Earth every fifty years. However, it was ultimately destroyed by Shadow the Hedgehog using the Eclipse Cannon in the present day when the comet posed a threat to the planet.

Fifty years before the present, aboard the Space Colony ARK, Professor Gerald Robotnik was forced by the President of the United Federation of that time to create the Ultimate Life Form in a project known as Project Shadow. After creating the Biolizard, which had many flaws, Gerald enlisted the help of Black Doom to create Shadow the Hedgehog. However, he saw the alien's plans, and built the Eclipse Cannon as a countermeasure, should he ever pose a threat in the future. At the same time, he studied a Gizoid, Chaos, and a Chaos Emerald. Eventually, the United Federation feared that Project Shadow would pose a threat to the world, and so GUN sent soldiers to kill anyone involved in the project. Gerald's granddaughter and Shadow's best friend, Maria Robotnik, was among those who died. In the midst of the conflict, she had sent Shadow down to Earth. GUN claimed the killing to be an accident, and Gerald was later found and imprisoned on Prison Island under the pretense of disappearance, and eventually executed.

In the present day, Earth has recently been pained by Gerald's grandson, Doctor Ivo "Eggman" Robotnik, with a number of his attacks and bases taking place in different types of islands and on Earth's natural satellite. It was also attacked by Perfect Chaos, threatened by an impact with the ARK, invaded by the Black Arms, nearly sucked into a giant black hole, broken apart and plagued by Dark Gaia, and had its very existence in space-time threatened on multiple occasions. All of these disasters were averted through the efforts of Sonic the Hedgehog and his friends, who used the power of the Chaos Emeralds (and sometimes other artifacts) to protect the world time and time again.

Parallel timelines and the future
Over 200 years after the present day, the people of the world had evolved to the point where they gained psychokinetic powers, which they would use in everyday life. During the centuries leading up to that point, Earth would be largely destroyed by Iblis. Admist Ibils's dark reign, a resident of the future named Silver tried to stop the demon's reign for good under Mephiles the Dark's machinations by time traveling to the present day to kill Sonic, whom he believed to be the "Iblis Trigger", the cause of Iblis's existence. When Solaris returned as a result, the deity sought to destroy all existing timelines, but was defeated by the combined efforts of Sonic, Shadow, and Silver. The deity was then erased from history by Sonic and Princess Elise of Soleanna. This caused these events to never happen, and, with the exception of Blaze the Cat, nobody would remember this negated timeline.

In this reformed future, Doctor Eggman Nega, a descendant of Doctor Eggman, tried to release a dimensional being called the Ifrit into Sonic's world in the past, which in turn changed Silver's future for the worse. To restore his time, the hedgehog went back in time to prevent the beast from destroying Sonic's world, and by extension his time.

Notable locations
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Islands

 * Angel Island
 * Cocoa Island
 * Christmas Island
 * Eggman Island
 * Flicky Island
 * Newtrogic High Zone
 * Prison Island
 * South Island
 * West Side Island

Main political factions

 * Eggman Empire
 * United Federation
 * Kingdom of Soleanna
 * style="vertical-align: top;" |

Cities and territories

 * Adabat
 * Apotos
 * Carnival Town
 * Central City
 * Chun-nan
 * Emerald Town
 * Empire City
 * Holoska
 * Mazuri
 * Metropolis
 * Monopole
 * Shamar
 * Soleanna
 * Spagonia
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Areas

 * GUN Fortress
 * Holy Summit
 * Mystic Ruins
 * Never Lake
 * North Cave

Natural satellites

 * Little Planet
 * Lost Hex
 * Moon
 * }

Archie
Main articles: Mobius (PSGW) and Mobius (SGW)

In the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics, the planet Mobius was originally the earth. In the early 21st century, the earth was contacted by the Xorda. However, the Xorda ambassador was captured and dissected by humanity, and the aggressive Xorda race declared war on earth. Though some of humanity managed to preserve themselves, the Xorda ended the world with their Gene Bombs which broke all forms of life down to their basic components. Thousands of years later, this combined biomatter gave birth to the Mobian race, who would repopulate the earth and rename it Mobius.

Following the events of Worlds Collide that rebooted the continuity, the planet now shares the same elements as its game counterpart. However, it also has its own exclusive elements, and Mobians now live side-by-side with humanity.

Sonic the Comic
Earth appeared in the British series Sonic the Comic, but in this continuity it is considered entirely separate from Sonic's home planet of Mobius. In an early Sonic's World strip, the Kintobor Computer claimed that Mobius was in a small galaxy that was "117,63222 light years from Earth", in a parallel dimension, in a different time zone and the whole region is made up of dark matter.

Despite this, later stories revealed that travel between the two worlds was possible. Amy Rose and Tekno the Canary crash-landed on Earth in a space ship after being accidentally teleported across the universe. During this short stay, they were mistaken for aliens. They befriended a human named Professor Cratermass and earned the enmity of Colonel Granite, the deranged commander of Operation Starwatch, who believed they were the vanguard of an invasion fleet. Amy and Tekno managed to escape and teleport back to Mobius with some help from Professor Cratermass, who deleted the teleportation program afterwards so that Colonel Granite couldn't follow. Amy and Tekno encountered Granite again on Earth during their trips through the Ring of Eternity, and as a result of this story, rogue British military forces led by Colonel Granite subsequently invaded Mobius before being hurled out by the spirit of the planet itself. An even later story showed that, due to their highly similar ecosystems, Earth and Mobius were twin planets.

X
Main article: Earth (X)

In Sonic X, it is revealed that Sonic, his friends and Dr. Eggman originate from an alternate reality version of Earth. A long time ago, Sonic's world and Earth were once one, but a cataclysmic event split the planet into two and sent them to different dimensions. The flow of time in Sonic's world is considerably slower than on Earth, with one month in Sonic's world equaling an entire year on Earth.

When Sonic came to Earth, the two worlds began to merge into one once again, which would ultimately stop the flow of time completely, thus forcing Sonic and co. to return to their world.

Trivia

 * In interviews, Takashi Iizuka said that the Sonic games takes place across two worlds―one is human, and one is set on the non-human side, the latter which Sonic Colors takes place in. However, it has not been clarified if whether this means the games literally take place across two different versions of the earth (like in Sonic X) or across different societies. The PR and Social Media Manager of Sonic the Hedgehog Aaron Webber (to his understanding) confirms the former while former Sega Europe community manager Kevin Eva disapproves the former. These conflicting statements is theorized to be due to the fluctuating canon of the Sonic games.