How to see Flying Saucers

Swezey, Kenneth: Popular Science, pp. 167-170,
Can you guess which of these kitchen saucers was farthest from Ken Swezey's camera and which nearest when he made this trick picture? Here's a tip: the photo was shot to demonstrate that unless you know the size of an unfamiliar object outlined against the sky, you can't judge its distance, and until you know its distance you can't possibly judge its speed. After making your guess, turn to the end of the story to see the answer.

Kitchen-table tricks suggest that those strange sights in the sky may be just optical illusions—and nothing more.

You don't have to stay up all night sky-gazing to catch a glimpse of some flying saucers. You can see them right in your own home, using just a milk bottle filled with water, a flashlight and a few other common gadgets.

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