No. 39: May-Jun 1985
"Our solar system may be inside the cloud of debris from a star that exploded 10,000 to 1,000,000 years ago. This startling conclusion was reached by Donald Clayton of Rice University after studying observations of the amount of aluminum-26 (26Al) in the interstellar medium."
Instruments on satellites (gamma-ray spectrometers) have detected so much aluminum-26 that radical hypotheses seem required. The problem is that aluminum26 is radioactive with a half-life of only about 1 million years -- a very short time astronomically speaking. The aluminum-26 cannot be primordial solar-system stuff; it cannot even be 10 million years old. It had to be created somewhere nearby recently. The best aluminum-26 factory conceived so far is a nova in our vicinity.
(Anonymous; "Are We inside a Supernova Remnant?" Sky and Telescope, 69:13, 1985.)
Comment. A nova close enough to engulf the earth with its debris must have had a profound effect on the earth and its cargo of life -- perhaps on Saturn's rings, too. See next item.
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