Convert Kilometers to Parsecs (km to pc) ▶
How to convert
1 parsec (pc) = 3.08568E+13 kilometer (km). Parsec (pc) is a unit of Length used in Metric system. Kilometer (km) is a unit of Length used in Metric system.
Parsec: A Unit of Length
A parsec is a unit of length that is often used in astronomy to measure the large distances to astronomical objects outside the Solar System. It is approximately equal to 3.26 light-years or 206,265 astronomical units (au), which are the average distances from the Earth to the Sun. One parsec is about 30.9 trillion kilometres or 19.2 trillion miles.
Definition of the parsec
The word parsec is a combination of “parallax” and “arcsecond”, which are terms related to the measurement of angles. Parallax is the apparent shift in position of an object when viewed from different perspectives. Arcsecond is a unit of angle that is equal to one sixtieth of an arcminute, or one three thousand six hundredth of a degree.
A parsec is defined as the distance at which one astronomical unit subtends an angle of one arcsecond. In other words, it is the distance from which the Earth-Sun distance would appear as one arcsecond on the sky. This can be illustrated by an imaginary right triangle, where the adjacent side is one au, the opposite side is one parsec, and the angle opposite to the parsec side is one arcsecond.
History of the parsec
The concept of the parsec was first proposed by the British astronomer Herbert Hall Turner in 1913, as a convenient unit for expressing stellar distances. He coined the term by blending “parallax” and “second”. He also suggested using the symbol “pc” for parsec.
The first measurement of a stellar parallax was made by Friedrich Bessel in 1838, for the star 61 Cygni. He found that the star had a parallax of 0.314 arcseconds, which corresponds to a distance of about 10.4 parsecs. Since then, many more stars have been measured for their parallaxes, using various methods such as telescopes, satellites and interferometers.
The parsec is now widely used in astronomy and astrophysics, especially for objects within and around the Milky Way galaxy. For more distant objects, such as galaxies and quasars, larger units such as kiloparsecs (kpc), megaparsecs (Mpc) and gigaparsecs (Gpc) are used.
How to convert parsec
To convert parsecs to other units of length, we can use the following conversion factors:
To convert other units of length to parsecs, we can use the inverse of these conversion factors:
Where parsec is used
The parsec is mainly used in astronomy and astrophysics, as it is a convenient unit for expressing distances between stars and other celestial objects. For example:
The parsec can also be used in other fields that deal with large distances or angles, such as geodesy, navigation and surveying.
Example conversions of parsec to other units
Here are some examples of converting parsecs to other units of length:
To convert one parsec to meters, we multiply by the conversion factor:
1 pc × 3.0857 × 10^16 m/pc = 3.0857 × 10^16 m
To convert 10 parsecs to miles, we multiply by the conversion factor:
10 pc × 1.9174 × 10^13 mi/pc = 1.9174 × 10^14 mi
To convert 0.01 parsecs to astronomical units, we multiply by the conversion factor:
0.01 pc × 2.06265 × 10^5 au/pc = 2.06265 × 10^3 au
To convert 100 parsecs to light-years, we multiply by the conversion factor:
100 pc × 3.26156 ly/pc = 326.156 ly
To convert one meter to parsecs, we divide by the conversion factor:
1 m / (3.0857 × 10^16 m/pc) = 3.24078 × 10^-17 pc
To convert one mile to parsecs, we divide by the conversion factor:
1 mi / (1.9174 × 10^13 mi/pc) = 5.21553 × 10^-14 pc
To convert one astronomical unit to parsecs, we divide by the conversion factor:
1 au / (2.06265 × 10^5 au/pc) = 4.84814 × 10^-6 pc
To convert one light-year to parsecs, we divide by the conversion factor:
1 ly / (3.26156 ly/pc) = 0.306601 pc
Kilometer - Unit of Distance / Length
Unit Symbol/Abbreviation: km
Where the unit used in the World:
The kilometer is used as a unit used to measure distances or lengths.
Definition of the Unit:
The kilometer (kilometre in UK spelling) is a unit of length/distance in the metric system (SI Unit system) equivalent to one thousand meters.
History of the Unit:
Although the meter was defined in 1799 in France, the kilometer was first adopted for everyday use by the Dutch in 1817 under local name of the mijl. The myriametre (10000 meters) and "lieues de Poste" (Postal leagues, 4288 meters) were preferred to the "kilometer" for everyday use in France in 19th century. In the mid 19th century the kilometer was already in everyday use in the Italy and in Netherlands and the myriametre was still in use in France. The CIPM (The International Committee for Weights and Measures) officially abolished the prefix "myria-" and the "myriametre" in 1935, leaving the kilometer as the recognised unit of length instead of myriametre.
Where it's used:
The kilometer is commonly used on road signs to indicate the distance to travel to a given location, on maps to indicate scale, for odometer indication in automotive industry. It is also the most popular unit for describing the distance between geographical points and locations.
Equivalents in other units and scales:
1 km is equivalent to 0.621371 mi.
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