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

A 'super-puff' planet like no other

The core mass of the giant exoplanet WASP-107b is much lower than what was thought necessary to build up the immense gas envelope surrounding giant planets like Jupiter and Saturn, astronomers at Université de Montréal ...

Cosmic beasts and where to find them

Two giant radio galaxies have been discovered with South Africa's powerful MeerKAT telescope. These galaxies are thought to be amongst the largest single objects in the Universe. The discovery has been published today in ...

Galaxies hit single, doubles, and triple (growing black holes)

When three galaxies collide, what happens to the huge black holes at the centers of each? A new study using NASA's Chandra X-ray Observatory and several other telescopes reveals new information about how many black holes ...

Neptune-sized exoplanet discovered by NGTS survey

An international team of astronomers reports the discovery of a new exoplanet as part of the Next Generation Transit Survey (NGTS). The newly found alien world, designated NGTS-14Ab, is about 30% larger than Neptune. The ...

Astronomers finally measure polarized light from exoplanet

An international team led by Dutch astronomers has, after years of searching and defying the boundaries of a telescope, for the first time directly captured polarized light from an exoplanet. They can deduct from the light ...

A new NASA space telescope, SPHEREx, is moving ahead

NASA's upcoming space telescope, the Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer, or SPHEREx, is one step closer to launch. The mission has officially entered Phase C, in NASA ...

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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