The Long Earth is a possibly infinite chain of parallel versions of the planet Earth. One analogy for it is a pack of cards - each card is an Earth, and the whole deck is the Long Earth.


Main article: Stepping

Traveling from one world in the Long Earth to another is called “Stepping", and for most humans requires the use of an inexpensive and easy-to-build device called a "Stepper Box".

The Stepper Box (or just ‘stepper') has a three way switch on top of it, one position marked ‘West', one 'off' and one 'East'. 'West' and 'East' are the names given to the two directions of travel possible through the Long Earth - flicking the switch to either causes the user to be transported one world in that direction.

Step Day

Main article: Step Day

The Long Earth was revealed to humanity on "Step Day", a day in 2015 when the circuit diagram for the Stepper Box was anonymously uploaded onto the Internet.

The Datum

Main article: Datum Earth

In all of the Long Earth, humans only evolved on one version of the planet, known as "Datum Earth", or "the Datum".

Worlds that don’t take many ‘steps’ to be reached from Datum Earth are very similar to it (apart from the absence of Homo sapiens). The further you travel through the Long Earth away from the Datum, the larger and more noticeable the differences become.

In the Long Earth, worlds are named after the amount of steps - either ‘West’ or ‘East’ - that need to be taken to reach it from the Datum. For example, 'Earth West 5' is located five steps West of Datum Earth.


Throughout The Long Earth series, several expeditions are made into the far Long Earth. The Journey was the first of these, undertaken in 2030 in the first “twain” - airship capable of stepping.

The East Twenty Million mission took place in 2040, and the West Quarter Billion mission in 2045.

Community content is available under CC-BY-SA unless otherwise noted.