I also have a question: Why do stars flicker at night?" I'm sure that most of us ... by the unstable state of the air through which a star's light must pass to reach our eyes.

Not all of these projectors were designed specifically for children, but these projector models captivate young minds with ...

Since 1986 I have had an affiliation with the Hayden Planetarium in New York. My "official" title there is "Associate and Guest Lecturer." Indeed, through all of these years I given scores of ...