Whirlwind, a general term for any whirling body of air. The term is most often applied to whirling air created by the swift rising of warm air from near the surface of the earth. Whirlwinds include the "dust devils" that may be seen moving across a field or along a dirt road on a hot day, and the waterspouts of tropical seas.
Some scientists believe that space is infinite. But is it? If it isn't, what form does space take? Is it a dodecahedron or a triple torus?
Folks in Montana usually expect snow or rain to fall from the sky, not ash. But the 1980 eruption of Mount St. Helens in Washington flung ash across state lines. What is this gritty, gray stuff?