The interior of a cometary nucleus

The interior of a cometary nucleus is probably full of holes, these having a size distribution that echoes that of the major snowball cometesimal components. Considering the compositional similarities between comets and the satellites of the outer planets, coupled with the “fractal” nature of cometary structure it is concluded that comets probably have mean densities in the 0.03–0.1 gcm−3 range. Comets are thus extremely fragile objects with very low surface strengths.