Earth

The "oldest and most advanced" parallel Earth. (COMIC: The Secret Origin of Jenny Everywhee)

Earth was, in a large number of worlds, the home planet of humanity.

History

Magician from Mars's universe

Size comparsion of Earth and Mars in one universe. (COMIC: On Earth)

In at least one universe, the Earth was the third planet in the Solar System, with the much smaller Mars being the fourth. (COMIC: On Earth) At some point beyond the 20th century, the inhabitants of Earth and Mars were in frequent contact, with “Earth-liner” space-ships regularly conveying travellers from one to the other. It appeared that Earth was the more advanced of the civilisations, with the space-ships being theirs. (COMIC: Magician From Mars…)

Lunar College Universe

Jenny Everywhere yells about being exiled from the one world's Earth.

Earth existed in one universe for some time past the 20th century.

The specifics of this version of Earth are unknown, although it was definitely populated by humans. Space travel was commonplace among the residents of this Earth, and a transport vessel would often carry people between Earth and its Moon, upon which the Lunar College of Selene had been established by earthlings, specifically those of the organization NASA.

Young geniuses of the planet were sent to the Lunar College, however, this was secretly part of a plan to stifle their intelligence, presumably to prevent some sort of uprising, suggesting a rather dystopian society. Nevertheless, IMAX documentaries are known to have existed there. (COMIC: Bacterial Lunarversity)

Universe of the shapeshifting Jenny

A rocket leaving Earth in one universe. (COMIC: Untitled)

In another universe, at an earlier point in time, NASA conducted experiments into rocket-launching with apes standing in for human pilots. The local Jenny Everywhere, who had used unluckily her shapeshifting powers to disguise herself as an ape, ended up being forced into the rocket instead, apparently becoming the first human being to leave her world's version of Earth. (COMIC: Untitled)

At the Edge of the Multiverse

It was alleged by the comic book Jenny Everywhere: Secret Origins that the "oldest and most advanced parallel Earth" had existed in a universe at the Edge of the Multiverse. The comic also asserted that it was the original homeworld of Jenny Everywhere and that it had been destroyed while she was a baby by a Living Black Hole. (COMIC: The Secret Origin of Jenny Everywhere)