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- <text id=92TT2271>
- <title>
- Oct. 12, 1992: Where Have You Been?
- </title>
- <history>
- TIME--The Weekly Newsmagazine--1992
- Oct. 12, 1992 Perot:HE'S BACK!
- </history>
- <article>
- <source>Time Magazine</source>
- <hdr>
- THE WEEK, Page 33
- HEALTH & SCIENCE
- Where Have You Been?
- </hdr><body>
- <p>Late by about a decade, a missing comet finally streaks into
- view
- </p>
- <p> Every August, comet Swift-Tuttle leaves a spectacular calling
- card. The trail of dust it sheds on its journey around the sun
- intersects Earth's orbit and flares into the Perseid meteor
- shower. The comet itself last appeared in 1862, and based on the
- orbit calculated at that time, it should have showed up again
- between 1979 and 1983. It didn't.
- </p>
- <p> But last week a Japanese comet hunter spotted a faint blob
- through powerful binoculars, and a check of its orbit confirmed
- that Swift-Tuttle had come back at last (it may be barely
- visible to the naked eye in November). Why so late? A comet's
- orbit is determined only by careful plotting of its position
- when it's visible; evidently the 1862 measurements were off. To
- his credit, Brian Marsden, of the Harvard-Smithsonian Center
- for Astrophysics, had argued in a 1973 paper that Swift-Tuttle
- might be late. Few astronomers paid attention -- but Marsden's
- prediction was only 17 days off.
- </p>
-
- </body></article>
- </text>
-
-