Page "Known Space" Paragraph 1

The epithet " Known Space " is an in-universe term that refers to a relatively small part of the galaxy centered around Earth.

In the future that the series depicts ( beginning a few centuries from now and continuing for about a millennium afterward ) this region has been explored by humans and a number of its worlds have been colonized.

Contact has been made with alien species such as the two-headed Pierson's Puppeteers and the aggressive felinoid Kzinti.

The fictional universe is also the home of species from outside Known Space, including the hominid inhabitants of a megastructure called Ringworld.

The Ringworld orbits a sun outside Known Space, but it is a well-established artifact within the Known Space " universe ".

The stories span approximately one thousand years of future history, from the first human explorations of the Solar System to the colonization of dozens of nearby systems.

Late in the series, this area is an irregularly shaped " bubble " about 60 light-years across.