Miniumbra

Miniumbra: noun. The shadow of an extremely small object. Generally miniumbras can only be seen under microscopes and even then, they are often confused with specks on the lens of the microscope, which they most definitely aren't. The first miniumbras were observed by Galileo Galilei through his telescope, when he was observing a nearby asteroid. This was before the definition of a miniumbra was specified, to only include things observed through microscopes. If a curious reader would like to see a miniumbra for himself, they are easily accessible through high-powered microscopes in well-protected government laboratories.