As reported by the Geophysical Institute at the University of Alaska Fairbanks, in 1974, seismologist Charles Richter of the California Institute of Technology called “The Jupiter Effect” predictions “pure astrology in disguise. In fact, it is very close to pure fantasy.” John Gribbin himself started walking back the book’s claims in 1980, stating in New Scientist that the theory had been “too clever by half.” According to Gribbin, if he and Stephen Plagemann had paid a little more attention to their calculations, they could have predicted the destructive and deadly 1980 eruption of Mount Saint Helen in Washington state. The Geophysical Institute staff noted that they’d received inquiries from the public wondering if they should prepare for catastrophe and sought to reassure worried readers that their fears brought on by reading “The Jupiter Effect” were unfounded.
In March of 1982, United Press International reported that Indian newspaper the Sunday Herald published an article predicting disease, riots, labor unrest, and possibly an earthquake, as well as “a strange epidemic affecting the abdomen will stalk India.” Others were acknowledging the so-called Jupiter Effect in more light-hearted manners. The planetarium at Arizona State University planned an “End of the World” party featuring a planetarium show based on the book and refreshments such as rapture punch, fire and sulfur dip, brimstone cookies, and flat Earth cake. Per coordinator Dan Matlaga, the planetarium received a number of calls from frightened people wondering what to expect: “Some people seem to thrive on predictions of calamity and mayhem. The one accompanying ‘The Jupiter Effect’ seems to have a lot of followers.”