No. 75: May-Jun 1991
No, comet Halley has not reversed direction for an anomalous encore. We'll have to wait another 70-or-so years for that. However, Halley did make a surprise reappearance on February 12, 1991. Astronomers were startled by a sudden flare-up. It was not a trivial brightening; the width of the flare was a remarkable 300,000 kilometers.
Comets often flare up as they swing close to the sun and absorb its heat and radiation. But Halley is now billions of kilometers away in the frigid reaches of the outer solar system. No one knows what happened. (Pease, Roland; "Halley at Large," Nature, 349:732, 1991.)
Comment. Other comets have mysteriously flared up far from the sun. See ACO2 in our catalog The Sun and Solar System Debris. Apparently comets harbor considerable pent-up energy. If proximity to the sun is not required to stimulate gas releases or chemical reactions, comets may have their own energy agenda. Comets seem to be little more than chunks of dirty ice. Where could the flare energy come from? If only cold fusion were a viable "acceptable" energy source!
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