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

Evidence for anisotropy of cosmic acceleration

The observed acceleration of the Hubble expansion rate has been attributed to a mysterious "dark energy" which supposedly makes up about 70% of the universe. Professor Subir Sarkar from the Rudolf Peierls Centre for Theoretical ...

Spacewalk excursion to extend the life of a powerful spectrometer

One of the largest human-made permanent magnets in space resides on the International Space Station (ISS), and it's helping scientists better understand the origins of our universe. The Alpha Magnetic Spectrometer (AMS-02) ...

The simultaneous merging of giant galaxies

An international research team led by scientists from Göttingen and Potsdam proved for the first time that the galaxy NGC 6240 contains three supermassive black holes. The unique observations, published in the journal Astronomy ...

The measurements of the expansion of the universe don't add up

Physicists use two types of measurements to calculate the expansion rate of the universe, but their results do not coincide, which may make it necessary to update the cosmological model. "It's like trying to thread a cosmic ...

Image: Orion A in infrared

Stars form within giant clouds of gas and dust that pervade galaxies like our own Milky Way. This image depicts one such cloud, known as Orion A, as seen by ESA's Herschel and Planck space observatories.

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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