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

Pandora's Cluster explored by researchers

Using the Magellan Telescopes in Chile, Italian astronomers have observed a giant galaxy cluster known as Abell 2744, dubbed the Pandora's Cluster. Results of the observational campaign, presented in a paper published February ...

Astronomers discover new supernova remnant

Astronomers from Curtin University in Australia and elsewhere report the detection of a new supernova remnant (SNR) located some 3,300 light years away. The newfound SNR, designated G321.3-3.9, has an elliptical shape and ...

Cosmic dark matter web detected in Coma cluster

The Subaru Telescope has spotted the terminal ends of dark matter filaments in the Coma cluster stretching across millions of light years. This is the first time that strands of the cosmic web spanning the entire universe ...

How dangerous are kilonovae?

When we look up at the sky on a particularly dark night, there is a sense of timelessness. We might see the flash of a meteor, and occasionally a comet is visible to the naked eye, but the cold and distant stars are unchanging. ...

page 1 from 2


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