The Earth Dimension is a dimension where Earth and other planets discovered by Earthlings are. Not many people in this dimension know about the Known Dimension. The dimension isn't divided up into universes. Not many civilizations are technologically advance. This is probably because the dimension is younger than others. It has only been around for about 14.7 billion years.
The Earth Dimension was named after the planet the first species (humans) discovered by Known Dimensionites, Earth.
The Earth Dimension was created 14.7 billion years ago. The first species to pop up were a species called worms. They populated some of the first planets. After a while, humans appeared. Their DNA was similar, but not identical to the DNA of humans of the Known Dimension. The Earth Dimension was discovered by Known Dimensionites in 216 CE by a few Dimension Hunters from Englia. These people wanted to one day control the Earthlings, so they secretly (to the humans and other universes) brought things such as the English Language and Latin. Other universes did the same, Chinagee and Japangee brought Chinese and Japanese, respectively. This is the reason why many places and cultures are similar to some in the Known Dimension.