Algol (Beta Per, β Persei, β Per), known colloquially as the Demon Star, is a bright star in the constellation Perseus. It is one of the best known eclipsing binaries, the first such star to be discovered, and also one of the first (non-nova) variable stars to be discovered. Algol is actually a three-star system (Beta Persei Aa1, Aa2, and Ab) in which the large and bright primary β Persei Aa1 is regularly eclipsed by the dimmer β Persei Aa2. Thus, Algol's magnitude is usually near-constant at 2.1, but regularly dips to 3.4 every 2.86 days (2 days, 20 hours and 49 minutes) during the roughly 10-hour-long partial eclipses. There is also a secondary eclipse (the "second minimum") when the brighter star occults the fainter secondary. This secondary eclipse can only be detected photoelectrically. Algol gives its name to its class of eclipsing variable, known as Algol variables.
An Ancient Egyptian Calendar of Lucky and Unlucky Days composed some 3200 years ago is claimed to be the oldest historical document of the discovery of Algol.
ALGOL (short for ALGOrithmic Language) is a family of imperative computer programming languages, originally developed in the mid-1950s, which greatly influenced many other languages and was the standard method for algorithm description used by the ACM in textbooks and academic sources for more than thirty years.
In the sense that most modern languages are "Algol-like", it was arguably the most successful of the four high-level programming languages with which it was roughly contemporary: Fortran, Lisp, and COBOL. It was designed to avoid some of the perceived problems with FORTRAN and eventually gave rise to many other programming languages, including BCPL, B, Pascal, PL/I, Simula, and C. ALGOL introduced code blocks and the begin
…end
pairs for delimiting them. It was also the first language implementing nested function definitions with lexical scope. Moreover, it was the first programming language which gave detailed attention to formal language definition and through the Algol 60 Report introduced Backus–Naur Form, a principal notation for language design.
This is a list of places featured in Douglas Adams's science fiction series, The Hitchhiker's Guide to the Galaxy. The series is set in a fictionalised version of the Milky Way galaxy and thus, while most locations are pure invention, many are based on "real world" settings such as Alpha Centauri, Barnard's Star and various versions of the Earth.
"The Galaxy" is our home galaxy, the Milky Way, though it is referred to exclusively as "the Galaxy" in the series. Apart from a very brief moment during the first radio series, when the main characters were transported outside the galactic plane into a battle with Haggunenons, and a moment when one of Arthur's careless remarks is sent inadvertently through a wormhole into "a distant galaxy", the Galaxy provides the setting for the entire series. It is home to thousands of sentient races, some of whom have achieved interstellar capability, creating a vast network of trade, military and political links. To the technologically advanced inhabitants of the Galaxy, a small, insignificant world such as Earth is considered invariably primitive and backward. The Galaxy appears, at least nominally, to be a single state, with a unified government "run" by an appointed President. Its immensely powerful and monumentally callous civil service is run out of the Megabrantis Cluster, mainly by the Vogons.
Algol, demon, capricious your brightness
shifts from day to day - rises, abates, intesifies
again, sometimes triumphant and sparkling,
sometimes pale and faint. For a long time
we've searched with wonder for the key
to this mystery, the right element to
your eager and changing, queer temperament.
Now we've dispearsed the haze of the riddle:
you've got a companion on your journey,
like a slave, a faithful shadow he
constantly follows you on the desolate
path, he circles and sneaks quiet around you, closely.
Never have we seen his guise, dark, parches,
stiff and cold, but still we know he exists;
like ashamed he hides behind you - free
and merry you shine - until he once
again crawls out of the darkness and
covers you. And your glare becomes
pallid and dull, and your mind cloudy.
Now we've dispearsed the haze of the riddle:
you've got a companion on your journey,
like a slave, a faithful shadow he
constantly follows you on the desolate
path, he circles and sneaks quiet around you, closely.
And similars there are - many Algols
wanders in the space - maybe even
more among us on earth. Sunlight spirits
darkened by a shadow, young princes
concealed by old slaves, doublesouls,
divided creatures - a blissful son of the
light indissolubely linked with a bitter dark demon.
Now we've dispearsed the haze of the riddle:
you've got a companion on your journey,
like a slave, a faithful shadow he
constantly follows you on the desolate