The term was coined by British astronomer Herbert Hall Hoover in 1913, and it’s the distance from the Sun to an object (like a star) that has a parallax angle of one arc-second. It’s the equivalent of 30.9 trillion kilometres (19.2 trillion miles), or about 3.26 light years. Parsec A large distance often used in astronomy. A parsec is a unit of length in astronomy. For example, Tatooine was less than a parsec away from Geonosis, and the Kamino system was located twelve parsecs south of the Rishi. The standard coordinate grid used by starship navigators to record the location of star systems was based on a scale with measurements of 15 parsecs. A light yearis the distance light travels in an average Gregorianyear (365.2425 days) in the near-vacuum of space. But before we define the parsec, let’s look at some more familiar units of astronomical distance: the light year (ly), and the astronomical unit (AU). Reminder: a parsec (a parallax of one arc-second, or arcsec) is a natural distance unit (for astronomers at least) because the astronomical unit (the length of the semi-major axis of the Earth’s orbit around the Sun, sorta) and arcsec are everyday units (again, for astronomers at least). all matter is crushed out of existence into what is known as a singularity. A parsec was a unit of astronomical distance equivalent to about 30.5 trillion kilometers (3.26 light-years). A parsec (pc) is a unit of distance that is often used by astronomers. Why do astronomers need to have such a large unit? When discussing distances like the size of a galaxy cluster, or a supercluster, or a void, the megaparsec is handy … just as it’s handy to use the astronomical unit (au) for solar system distances (for single galaxies, 1,000 parsecs – a kiloparsec, kpc – is a more natural scale for cosmological distances, a gigaparsec (Gpc) is sometimes used). A megaparsec is a million parsecs (mega- is a prefix meaning million think of megabyte, or megapixel), and as there are about 3.3 light-years to a parsec, a megaparsec is rather a long way.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |