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

New planet discovered in orbit of young Milky Way star

A second planet has been discovered circling Beta Pictoris, a fledgling star in our own galaxy offering astronomers a rare glimpse of a planetary system in the making, according to a study published Monday.

Total annihilation for supermassive stars

A renegade star exploding in a distant galaxy has forced astronomers to set aside decades of research and focus on a new breed of supernova that can utterly annihilate its parent star—leaving no remnant behind. The signature ...

A new lens for life-searching space telescopes

The University of Arizona Richard F. Caris Mirror Laboratory is a world leader in the production of the world's largest telescope mirrors. In fact, it is currently fabricating mirrors for the largest and most advanced earth-based ...

Star nearing death offers a preview of our Sun's fate

An international team of astronomers has witnessed a rare dynamic event foreshadowing the death of a red giant star for the first time – a discovery that reinforces predictions about our Sun's ultimate demise.

Storming Area 51 to find aliens? Here's some science to consider

Millions of people have signed up to a tongue-in-cheek Facebook event to storm the US military base "Area 51" on 20 September to discover whether aliens are inside. While the organisers said it was a joke, the US military ...

New space discovery sheds light on how planets form

Researchers at Dartmouth College have discovered a planet orbiting one of the brightest young stars known, according to a study published in the journal The Astrophysical Journal Letters. Aged at approximately 45 million ...

Gaia starts mapping the galactic bar in the Milky Way

The second release of data from the Gaia star-mapping satellite, published in 2018, has been revolutionising many fields of astronomy. The unprecedented catalogue contains the brightness, positions, distance indicators and ...

Moon-forming disk discovered around distant planet

Using Earth's most powerful array of radio telescopes, astronomers have made the first observations of a circumplanetary disk of gas and dust like the one that is believed to have birthed the moons of Jupiter.

page 1 from 23

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