On Radiation Pressure and the Poynting-Robertson Effect for Fluffy Dust   Particles
  Equation of motion for real dust particle under the action of electromagnetic radiation is more general than equation of motion corresponding to standardly used Poynting-Robertson effect (P-R effect). As a consequence, orbital evolution of particles may significantly differ from that corresponding to the P-R effect. The paper discusses recently published (Icarus, June 2002) derivation of equation of motion, which is in contradiction with known relativistically covariant formulation. The ``new'' derivation does not respect fundamental physical laws (law of conservation of energy, law of conservation of momentum) which must hold in any frame of reference. Application of the derived ``general'' equation of motion to the special case treated by Einstein in 1905 yields result which is not consistent with Einstein's result. Correct solution is presented. 
Jozef Klacka