Solarian (Proof)

The Solarians are a sapient species of spherical beings native to the interior of Sol. They possess the means to create spaceships which allow them to travel to other nearby star systems such as Sirius and Procyon; and seem to maintain friendly contact with other star-dwelling species such as the Sirians. Despite their advanced technology, they remain unaware of the existence of planets and skeptical of the very idea that atomic matter could naturally exist in the solid state.

Biology
The Solarian body is made of a field of closely packed electrons surrounding a core of neutronium. They feed on solar radiation, which is used to synthesize neutronium on their skin, which is then transported to their interior by a kind of "circulatory system" formed from magnetic fields. They have no limbs or appendages, and instead manipulate their environment by projecting force beams and force fields. Their sense organs detect not only electromagnetic radiation (such as gamma rays and radio waves) but also other kinds of energy which remain unknown to humans.

Culture and society
Since the core regions of the sun are infested with predators, the Solarians prefer to build disk-shaped floating cities in the upper layers of the photosphere: an incredibly cold and inhospitable environment for them. Their architecture is based on various geometric forms, with buildings that resemble cones, cylinders, prisms and hemispheres.

Appearances

 * "Proof", by Hal Clement (1942)