Galactic Kites

TL;DR

This paper proposes that ultra-thin interstellar films, formed naturally or artificially, can drift above the Galactic plane due to radiation pressure, accumulating over cosmic timescales and constrained by starlight scattering observations.

Contribution

It introduces the concept of interstellar films as a new class of Galactic structures influenced by radiation pressure and dark matter, with implications for interstellar medium composition.

Findings

Interstellar films can hover above the Galactic plane at a scale height determined by dark matter.

Such films constitute less than 0.2% of the interstellar medium mass.

Limits on scattered starlight restrict their total mass fraction.

Abstract

I show that interstellar films of material thinner than a micron, drift away from the Galactic plane as a result of stellar radiation pressure. Such films, whether produced naturally by dust coagulation in proto-planetary disks or artificially by technological civilizations, would accumulate over the age of the Milky-Way and hover above the Galactic disk at a scale-height set gravitationally by the dark matter halo. Limits on scattered starlight imply that this population carries a fraction below 2x10^{-3} of the interstellar medium mass.