Dr. Universe

Asked by Ms. Flores and her fourth grade students in East Alton, Ill.

Dear Ms. Flores and 4th graders,

There’s wind in the Alton, Illinois, forecast this week, so it’s prime time for an answer. In fact, it looks like there’s wind all around Earth and even some gusts out on other planets.

My friend Nic Loyd, a meteorologist at Washington State University, studies all kinds of weather. He told me the simple answer: Wind is moving air.

We thought you might want to know more about how it works.

Wind happens both because of how the sun heats up the Earth and the tiny air molecules that move around...