Phil Sadler of the Smithsonian Astrophysical Observatory shows how to bring the cosmos down to size by using the processes of any scientific investigation: selecting a specific problem, collecting data, and building a model that both explains our observations and accurately predicts future findings.

Entomologist C. J. Geraci and colleague Michael Biondi explain the importance of this information and demonstrate a new way of precisely measuring biodiversity — a web-based application for mapping the distribution of beetles and canopy trees in two rainforest plots. They then show how to use...