  The blackbody radiation problem within classical physics is reviewed. It is
again suggested that conformal symmetry is the crucial unrecognized aspect, and
that only scattering by classical electromagnetic systems will provide
equilibrium at the Planck spectrum. It is pointed out that the several
calculations of radiation scattering using nonlinear mechanical systems do not
preserve the Boltzmann distribution under adiabatic change of parameter, and
this fact seems at variance with our expectations in connection with
derivations of Wien's displacement theorem. By contrast, the striking
properties of charged particle motion in a Coulomb potential or in a uniform
magnetic field suggest the possiblity that these systems will fit with
classical thermal radiation. It may be possible to give a full scattering
calculation in the case of cyclotron motion in order to provide the needed test
of the connection between conformal symmetry and classical thermal radiation.
