On the possibility of the Dyson spheres observable beyond the infrared spectrum

Abstract: In this paper we revisit the Dysonian approach and assume that a superadvanced civilisation is capable of building a cosmic megastructure located closer than the habitable zone (HZ). Then such a Dyson Sphere (DS) might be visible in the optical spectrum. We have shown that for typical high melting point meta material - Graphene, the radius of the DS should be of the order of $10^{11}$cm, or even less. It has been estimated that energy required to maintain the cooling system inside the DS is much less than the luminosity of a star. By considering the stability problem, we have found that the radiation pressure might stabilise dynamics of the megastructure and as a result it will oscillate, leading to interesting observational features - anomalous variability. The similar variability will occur by means of the transverse waves propagating along the surface of the cosmic megastructure. In the summary we also discuss the possible generalisation of definition of HZs that might lead to very interesting observational features.