Cosmic distance ladder

The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.

Standard Candles

Standard Candles (1996, ISBN 0-9648320-4-6) is a compilation of short stories by American science fiction author Jack McDevitt. The sixteen stories in the anthology were originally published in various magazines from 1982 to 1996. The introduction is provided by Charles Sheffield.

Like many of the author's works, the title story is set at an astronomical observatory and refers to a star's absolute brightness, connecting that phenomenon with the relationship between two individuals in the story. No matter where one stands, the light radiates at the same level of intensity. ("Standard Candles", "Ellie", and "Cryptic")

Other stories in the collection deal with chess ("Black to Move" and "The Jersey Rifle"), time travel with unintended consequences ("Cruising Through Deuteronomy" and "Time Travelers Never Die"), and the beginnings of interplanetary exploration ("Translations from the Colosian", "Promises to Keep", and "To Hell with the Stars", the last an exposition of what may happen if humanity chooses to not enter space).