Any classical description of nature requires classical electromagnetic zero-point radiation

Any attempt to describe nature within classical physics requires the presence of Lorentz-invariant classical electromagnetic zero-point radiation to account for the Casimir forces between parallel conducting plates at low temperatures. This zero-point radiation leads to classical explanations for several phenomena that are usually regarded as requiring quantum physics. We provide a brief overview of classical electromagnetic theory including classical zero-point radiation and note the areas of agreement and disagreement between the classical and quantum theories, both of which contain Planck's constant. (C) 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3630939]