Astronomy Cast Ep. 336: Units of Measure - HD
Channel: astrospherevids
Date: 2014-03-05

This video is sponsored by XE.com 
and Swinburne Astronomy Online (http://astronomy.swin.edu.au/sao/)

How heavy is a kilogram, how long is a second? How warm is a degree? We measure our Universe in so many different ways, using different units of measurement. But how do scientists come up with measurement tools which are purely objective?
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Images by Isabelle Grosjean, Aldaron and Toby Hudson.