Aeronautics, the science and practice of aircraft flight. (An aircraft is a vehicle that is supported in flight by its own buoyancy or by the action of air on its surfaces.) The term aeronautics takes in all phases of the design, construction, and operation of both lighter-than-air craft (airships and balloons) and heavier-than-air craft (such as airplanes, helicopters, convertiplanes, autogiros, gliders, and kites). The term aviation is usually restricted to powered, heavier-than-air craft.
On one hand, nuclear power offers a clean energy alternative that decreases fossil fuel dependence. On the other, it summons images of quake-ruptured Japanese power plants belching radioactive steam. What happens in reactors in good times and bad?
Mathematics achieves the sublime. Sometimes, as with tessellations, it rises to art. In their simplest form, tessellations consist of a single shape that repeats over a two-dimensional plane without any gaps. Why was M.C. Escher so fixated on them?