Another tale of Halley



The news services seem disappointed by Comet Halley's modest performance this time around, but my enthusiasm for the spectacle is undiminished. For me, the comet's 76-yr orbital period highlights a compressed history reckoned by generations. Shifting into cometary overdrive, merely 30 orbits give a stroboscopic view of events since 240 B.C., when the earliest known visit was recorded. Just four backward ticks on the clock take us to Edmund Halley's realization that the bright comet of 1682 was the same one reported many times earlier. By its visible presence this year, the comet offers only its fourth confirmation of Halley's prediction, and with such close perspective, we become fascinated observers in a cosmic physics experiment.