Rebecca Rota, age 10, of Lansing, Mich., for her question:

How did Halley's comet get its name?

It was named for the astronomer who predicted when it would return for a razzle dazzle spin around the sun. But Old Andy thinks that it might well have been called the Christmas Comet. No, it does not appear at this time of year on every trip. But in its long career it did make two Christmas trips. Astronomers suspect that Halley’s comet was the glorious Star of Bethlehem.

William Halley searched old records of the heavens and found that this bright comet appears once in about 77 years. He predicted that it would make its next appearance in the winter of 1759. It appeared on schedule, again at Christmas time, though William Halley did not live to see his prediction come true.