A parsec is an astronomical measure of length that stands for "parallax arc-second". It is based on the Earth method of measuring interstellar distances using trigonometry. A star located one parsec away from an observer would have a "parallax angle" of one arc-second.
Comparative list of lengths
Each of the following gives a conversion to IAU light years, with appropriate use of significant digits.
- The USS Enterprise-D was 2.2 milliparsecs from the USS Lantree. There were no other vessels within two parsecs of there. (TNG: "Unnatural Selection")
- The USS Enterprise was one-sixteenth of a parsec from 892-IV when it identified the SS Beagle debris. (TOS: "Bread and Circuses")
- The Enterprise used sensors to scan a one-half parsec radius, then increased to a one parsec radius. (TOS: "The Enterprise Incident")
- The Enterprise-D was supposedly thrown 0.54 parsecs from their position near the Paxans' homeworld. (TNG: "Clues")
- The Enterprise was to pass one parsec from a Klingon outpost. Pavel Chekov thought this was "close enough to smell them." (TOS: "The Trouble with Tribbles")
- According to Data's reading of inertial guidance, the Enterprise-D traveled 1.4 parsecs in Nagilum's void without finding any sign of an exit. (TNG: "Where Silence Has Lease")
- Zalkon was 2.3 parsecs distant from where the Zalkonian warship met the Enterprise-D. (TNG: "Transfigurations")
- When the interphase began, the Enterprise was thrown 2.72 parsecs from where the Tholians' field captured them. (TOS: "The Tholian Web")
- The regions of space known as 2279 PL and 2466 PM are both located approximately 22.3 parsecs beyond Cestus III and the Federation's chart limits during the late 23rd century. (TOS: "Arena")
- The Vega Nine probe traveled 23 parsecs beyond the borders of the Federation, as well as any manned expeditions, to explore the Beta Stromgren system. (TNG: "Tin Man")
- All Starfleet units and personnel were evacuated from an area covering 100 parsecs from the planet where Lazarus was found. (TOS: "The Alternative Factor")
- The unexplored region where the Metrons stopped the Enterprise and the Gorn ship occupied 1,000 cubic parsecs. The Metrons later hurled Enterprise 500 parsecs distant. (TOS: "Arena")
- At 98% of its pre-temporal flux strength, the Krenim Imperium spanned 5,000 parsecs of the Delta Quadrant. (VOY: "Year of Hell")