In Hyperborea’s northernmost mountains, there exists a sanctuary where comets come to roost. Here, natural philosophers have been able to observe some of their more avian characteristics up close: their bodies are covered from nucleus to tail in transparent feathers, and their parrot-like faces can be vaguely discerned underneath the icy mists that surrounds them. Their wings are extraordinary in span, yet are never unfurled during their travels through space, as there is no atmosphere against which to propel themselves.