Related topics: galaxies · stars · black holes · nasa · astronomers

Astronomers inspect open cluster Berkeley 50

Using the Lowell Discovery Telescope (LDT), astronomers from the Lowell Observatory in Flagstaff, Arizona, have observed a young Galactic open cluster known as Berkeley 50. Results of the observational campaign, presented ...

Luminous quasar PDS 456 explored with MUSE

Using the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) in Chile, an international team of astronomers has inspected a luminous quasar known as PDS 456. Results of the observational campaign, ...

page 1 from 40

Light-year

A light-year or light year (symbol: ly) is a unit of length, equal to just under 1013 kilometres. As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year.

The light-year is often used to measure distances to stars and other distances on a galactic scale, especially in non-specialist and popular science publications. The preferred unit in astrometry is the parsec, because it can be more easily derived from, and compared with, observational data. The parsec is defined as the distance at which an object will appear to move one arcsecond of parallax when the observer moves one astronomical unit perpendicular to the line of sight to the observer, and is equal to approximately 3.26 light-years.

The related unit of the light-month, roughly one-twelfth of a light-year, is also used occasionally for approximate measures.

This text uses material from Wikipedia, licensed under CC BY-SA