Frank and Sigwarth [1993, 1999> have promoted the hypothesis of a population of small house-sized comets in near-parabolic orbits that are nearly tangent with the Earth's and rain down on the Earth at a rate of ~20/min. The hypothesis is based on holes in the dayglow of the Earth's atmosphere, which they first claimed to see in images from the Dynamics Explorer 1 satellite, and more recently in images from the Polar satellite. One of the key aspects of the claimed observations is that the atmospheric holes appear to be more numerous on the morning hemisphere of the Earth, to which Frank and Sigwarth draw analogy to radar meteors, which show a similar asymmetry. In this paper, I show that the distribution of orbits posited by Frank and Sigwarth yield a maximum flux in the afternoon, the opposite asymmetry from the claimed observations. The only orbits which yield the correct diurnal asymmetry, and preserve acceptably low entry speeds, are orbits interior to the Earth's having perihelia near the orbit of Mercury. Thus any relationship of atmospheric holes to small comets, or icy bodies from the outer solar system, can be ruled out. ¿ 2000 American Geophysical Union