Halley's Comet: What We've Learned

School Library Journal

Gr 9-12 Libraries are well stocked with Halley's comet booksall out of date. A wealth of new data from last year's return of the famous comet has changed and re fined astronomers' descriptions of Halley and comets in general. Thanks to Vogt's book readers can learn, in great detail, what astronomers discovered. The first part of the book relates the now standard history of how Halley, with the help of Newton, realized the periodic nature of the great comet. But it's the second part, discussing recent discoveries, where the book sparkles. With a sense of drama, Vogt introduces the cast of robot space craft launched to observe Halley. One by one they approach and, despite damaging collisions with minute dust particles, probe the heart of the comet. Anyone hun gry for facts about the comet will be satis fied by the wealth of numbers this book produces: everything from comet chemis try to angles and speeds of spacecraft en counters to the surface reflectance of the comet. Just the book to complete every library's collection on Halley's comet. Alan Newman, Johns Hopkins University, Baltimore