Micromegas

Micromegas, an inhabitant of one of the planets that orbits Sirius.

His home world is 21.6 million times greater in circumference than the Earth.

Micromegas stands 23 miles tall. When he is almost 450 years old, approaching the end of his infancy, Micromegas writes a scientific book examining the insects on his planet, which at 30 m are too small to be detected by ordinary microscopes.