Nuclear timescale

In astrophysics, the nuclear timescale is an estimate of the lifetime of a star based solely on its rate of fuel consumption. Along with the thermal and dynamical time scales, it is used to estimate the length of time a particular star will remain in a certain phase of its life and its lifespan if hypothetical conditions are met. In reality, the lifespan of a star is greater than what is estimated by the nuclear time scale because as one fuel becomes scarce, another will generally take its place—hydrogen burning gives way to helium burning, etc. However, all the phases after hydrogen burning combined typically add up to less than 10% of the duration of hydrogen burning.

Stellar astrophysics

Hydrogen generally determines a star's nuclear lifetime because it is used as the main source of fuel in a main sequence star. Hydrogen becomes helium in the nuclear reaction that takes place within stars; when the hydrogen has been exhausted, the star moves on to another phase of its life and begins burning the helium.

Time scale

Time scale may refer to:

In astronomy and physics:

In cosmology and particle physics:

Rhythm

Rhythm (from Greek ῥυθμός, rhythmos, "any regular recurring motion, symmetry" (Liddell and Scott 1996)) generally means a "movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions" (Anon. 1971, 2537). This general meaning of regular recurrence or pattern in time can apply to a wide variety of cyclical natural phenomena having a periodicity or frequency of anything from microseconds to millions of years.

In the performance arts rhythm is the timing of events on a human scale; of musical sounds and silences, of the steps of a dance, or the meter of spoken language and poetry. Rhythm may also refer to visual presentation, as "timed movement through space" (Jirousek 1995, ) and a common language of pattern unites rhythm with geometry. In recent years, rhythm and meter have become an important area of research among music scholars. Recent work in these areas includes books by Maury Yeston (Yeston 1976), Fred Lerdahl and Ray Jackendoff, Jonathan Kramer, Christopher Hasty (Hasty 1997), Godfried Toussaint (Toussaint 2005), William Rothstein, and Joel Lester (Lester 1986).

Nuclear Time

Nuclear Time is a BBC Books original novel written by Oli Smith and based on the long-running British science fiction television series Doctor Who. It features the Eleventh Doctor along with Amy Pond and Rory Williams.

Synopsis

In Colorado in 1981, The Doctor, Amy and Rory arrive in Appletown, an idyllic village in the middle of the American desert where the townsfolk go peacefully about their routines. However, all is not as it seems. The village is populated by murdering robots who will kill the moment their cover is blown: 5 minutes in the Doctor's case. While Amy and Rory run and hide in the town, the Doctor is trapped, going backwards in time and getting ever further away.

The awful truth dawns on him: Appletown is a dummy, a prefabricated town awaiting destruction by Nuclear bomb, designed to kill the robots. Can the Doctor get himself, Amy and Rory out while he is going backwards and the TARDIS is stuck at ground zero containing the nuclear blast.

See also

References