A parsec is equal to 3 26 light-years Why such a strange number? I'll leave that one up to Edward L (Ned) Wright's Web Page on distances
A unit of length approximately equal to 3 26 light-years, or nineteen trillion miles
Unit of measure used by astronomers to express distances to stars and galaxies. It is the distance at which the radius of Earth's orbit would subtend an angle of one second of arc, so an object one parsec away would have a parallax of one second. An object's distance in parsecs is the reciprocal of its parallax in seconds of arc. For example, Alpha Centauri, with a parallax of 0.76 second, is 1.33 parsecs from the Sun and Earth. One parsec equals 3.26 light-years, or 19.2 trillion mi (30.9 trillion km)
A PARallax SECond The diagram (right) shows how it is defined The Earth's orbit is shown around the Sun Over a period of 6 months, we move from A to B A nearby star (white) will appear to change position against the background of more distant stars (not shown) The angular change in position (parallax) that the star undergoes is p The parsec is defined as being the distance d for which p is 1 arc-second No star is quite this close, but this unit is useful as if one can measure parallax, you can instantly find the distance in parsecs
A historical unit of distance equal to 3 26 light years A megaparsec is one million parsecs, while a gigaparsec is one billion parsecs
The distance at which a star must lie in order that its measured parallax is exactly 1 arc second, equal to 206,000 A U
(pc): distance at which an object would have a parallax of one arc second Equals approximately 3 26 light years or about 206,265 astronomical units
a unit of measurement often used for interstellar or intergalactic distances; approximately equal to 3 2616 light years
A unit of distance equal to about 3 26 light-years (or, more precisely, equal to 206,265 Astronomical Units) Technically, a parsec is defined to be the distance from which the Earth and Sun would appear to be separated from one another by 1 second of arc (about the size a dime would appear to be if seen from a distance of 2 miles)
Abbreviated pc Another unit of stellar distance, frequently used in place of the light-year, is derived from the Parralax method This unit is the distance at which a star has a parallax of one second of arc One Parsec = 3 26 light years, or 206,265 Astronomical Units The distance to Proxima Centauri, for example, is 1 3 pc
A unit for expressing large distances It is the distance at which a star would have a parallax of one arc second, equal to 3 2616 light years, 206,265 astronomical units (AU) or 30 857 * 10E12 km
from parallactic arcsecond A parsec (abbreviated pc) is the distance at which a star or other object shows a parallax of one arcsecond due to the motion of the Earth around the Sun One parsec is exactly equal to 648000/pi AU, and approximately equal to 206265 AU, 3 086e16 m, 1 917e13 mi, and 3 2616 lightyears A kiloparsec (abbreviated kpc) is 1000 pc (or about 3262 lightyears), a megaparsec (abbreviated Mpc) is 1,000,000 pc (or about 3 million lightyears), and a gigaparsec (abbreviated Gpc) is 1,000,000,000 pc
One second of arc or a measure of distance approximately equal to 3 26 light years