Free Astronomy Quiz

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  2. Terminology - L

As with any field of scientific study, astronomy has a long list of important terminology. So we've put together this glossary where you can check you fully understand the meaning of the common terms, as well as some of the more unusual words.



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Words beginning with 'L' :



Light year : is the distance light travels in a year through vacuum. It is a measure of distance and not time. Light year = 9.46 x 1012 km Limb : the visible edge of an astronomical object's disk.

Luminosity : the measure of an astronomical object's brightness. It is defined as the amount of energy it emits over a fixed period of time. In astronomy the luminosity of an object is often compared to the luminosity of the Sun and expressed as a ratio of that luminosity; for example 25 L⊙.

Lunation : the period between new Moons (about 291/2 days), a lunar month.




Resources :


To support the quizzes in each section, we've put together some extra resources to provide further information: