In the outer quadrants, the colony worlds run by the major political groupings represent significant financial investments, and a source of materials and trade with the home systems.

Limited only by the economic journey times, human developed space is a region about 300-360 parsecs across.  Within that space, no other sentients have been found, humankind being the dominant sentient species everywhere.
Rumours persist about aliens and ancient 'forerunner' civilisations, but the only hard evidence of existing aliens is in the dangerous Exterminator machines currently threatening human space (and then only in Quadrants 5, 6 and 7).

The map shows only those systems suitable for human life and colonisation. For every one system shown on the map there are tens or hundreds of others unsuitable because of too deep an M25, too high radiation, no suitable planets, or some other simliar reason. Outside the mapped Quadrants, there are still more systems containing suitable worlds. These are called Sectors and all the un-named systems in these sectors contain no colonists.

Distance

For those unfamiliar with the terminology of the distances we use in the Universe, here is a handy table:

Unit	defintion	approximate length expressed in kilometres	approximate length expressed in AU	approximate length expressed in light-years	approximate length expressed in parsecs
Astronomical Unit (AU)	The mean distance between the Earth and the Sun	150,000	1.0	-	-
Light Year	The distance light travels in a year	10,000,000,000,000	67,000	1	0.31
Light Octant	The distance light travels in 50 days	1,250,000,000,000	8,300	0.13	0.04
Light Day	Thedistance light travels in a day	25,000,000,000	167	-	-
Light Hour	The distance light travels in an hour	1,000,000,000	6.94	-	-
Light minute	The distance light travels in a minute	17,000,000	0.12	-	-
Parsec	Defined by a trigonmetric calculation based on the Earth's orbit.	32,600,000,000,000	217,000	3.26	1.0

Most measurements within the M25 of a system is in terms of AU. All measurements on the interstellar scale are in parsecs.

Note also that the Light Hour and Light Minute distances are useful in defining how long it takes transmissions to travel when communicating inside the M25 of a system.