A new member of a growing class of unresolved second law paradoxes is examined.(1–7) In a sealed blackbody cavity, a spherical gravitator is suspended in a low density gas. Infalling gas suprathermally strikes the gravitator which is spherically asymmetric between its hemispheres with respect to surface trapping probability for the gas. In principle, this system can be made to perform steady-state work solely at the expense of heat from the heat bath, this in apparent violation of the second law of thermodynamics. Detailed three-dimensional test particle simulations of this system support this prediction. Standard resolutions to the paradox are discussed and found to be untenable. Experiments corroborating a central physical process of the paradox are discussed briefly. The paradox is discussed in the context of the Maxwell demon.