Showing posts from September, 2012

Sizing up a new measuring ruler for the solar system

Source:  Jacob Aron, NewScientist Excerpt:  At … the IAU in Beijing, China, members unanimously voted to redefine the astronomical unit, or AU, which has long served as the fundamental unit of distance between objects in the solar system. … the official definition of the AU is now exactly 149,597,870,700 metres, and the unit should be written "au". Historically, calculating the astronomical unit was based on the average distance between Earth and the sun, or 149,597,870,691 metres. An amendment in 1976 complicated things by also tying the unit to the sun's mass. Although the recent decision doesn't alter the value by much, it simplifies things and should improve the accuracy of distance measurements over time..