A megaparsec (Mpc) is a unit of measurement used in astrophysics and cosmology to express vast distances on cosmic scales. It is equal to one million parsecs. A parsec (pc) is a unit of length used in astronomy to describe astronomical distances, and it is approximately equal to 3.09 × 10^16 meters or 3.09 × 10^13 kilometers.
So, a megaparsec is equivalent to:
1 megaparsec (Mpc) = 1,000,000 parsecs (pc)
Megaparsecs are typically used to describe distances between galaxies and galaxy clusters in the universe. Since astronomical distances are extremely large, the parsec and its multiples, such as the megaparsec, provide a convenient way to express these distances without dealing with unwieldy numbers of kilometers or light-years. Cosmologists often use megaparsecs when discussing the large-scale structure of the universe, the size of galaxy clusters, and the expansion of the cosmos.
A "pole" is a unit of length that is equivalent to 16.5 feet or 5.0292 meters. It is sometimes referred to as a "rod" or a "perch," and these terms are often used interchangeably. Poles, like rods and perches, were historically used in some English-speaking countries, primarily in the United Kingdom and the United States, for land measurement, surveying, and real estate.
While the use of poles, rods, and perches has become less common in modern times, you may still encounter these units of length in certain contexts, especially in older land descriptions or surveys. In everyday measurements and official standards, more commonly used units like meters or feet are preferred.