Changes

[[Liberal]] [[Astronomy|astronomers]] have searched for ways to determine the age of a [[star]] in keeping with their cosmology. A new technique called '''gyrochronology''', which works this out based on the star’s rate of rotation, has just been announced and will be published in the ''Astrophysical Journal''. <ref> http://www.astronomy.com/asy/default.aspx?c=a&id=5479</ref> Knowing the age of the host star of a [[planetary system]] helps astronomers understand how planetary systems change over time.  

[[Liberal]] [[Astronomy|astronomers]] have searched for ways to accurately determine the age of a [[star]] in keeping with their cosmology. A new technique called '''gyrochronology''', which works this out based on the star’s rate of rotation, has just been announced and will be published in the ''Astrophysical Journal''. <ref> http://www.astronomy.com/asy/default.aspx?c=a&id=5479</ref> Knowing the age of the host star of a [[planetary system]] helps astronomers understand how planetary systems change over time.  

The research shows that the rotation period of a star changes steadily and predictably in line with its age and color. Thus, by measuring two of these attributes you can determine the third. The star’s color is a visible sign of its [[mass]] or surface temperature. The age of the [[Sun]] is believed by astronomers to be 4.6 billion years <ref> http://cosmos.phy.tufts.edu/~zirbel/ast21/handouts/Energy-of-Sun-better.PDF </ref> and can be used to calibrate the gyrochronology of most other stars.  This apparently circular set of assumptions is, of course, vociferously contested by conservative [[Young Earth Creationism|Creationists]].   

The research shows that the rotation period of a star changes steadily and predictably in line with its age and color. Thus, by measuring two of these attributes you can determine the third. The star’s color is a visible sign of its [[mass]] or surface temperature. The age of the [[Sun]] is believed by astronomers to be 4.6 billion years <ref> http://cosmos.phy.tufts.edu/~zirbel/ast21/handouts/Energy-of-Sun-better.PDF </ref> and can be used to calibrate the gyrochronology of most other stars.  This apparently circular set of assumptions is, of course, vociferously contested by conservative [[Young Earth Creationism|Creationists]].