  The heat radiated by objects small or comparable to the thermal wavelength
can be very different from the classical blackbody radiation as described by
the laws of Planck and Stefan-Boltzmann. We use methods based on scattering of
electromagnetic waves to explore the dependence on size, shape, as well as
material properties. In particular, we explore the radiation from a long
cylinder at uniform temperature, discussing in detail the degree of
polarization of the emitted radiation. If the radius of the cylinder is much
smaller than the thermal wavelength, the radiation is polarized parallel to the
cylindrical axis and becomes perpendicular when the radius is comparable to the
thermal wavelength. For a cylinder of uniaxial material (a simple model for
carbon nanontubes), we find that the influence of uniaxiality on the
polarization is most pronounced if the radius is larger than a few microns, and
quite small for submicron sizes typical for nanotubes.
