Graham Hancock on science: what the evidence says · JRE #1284
SUBJECT: SCIENCE
The short answer
Hancock claims Comet Shoemaker-Levy 9's 1994 impact with Jupiter released 300 gigatons of energy, roughly 47 times the explosive yield of the world's entire nuclear arsenal (stated as 6.4 gigatons). A 1997 Sandia National Laboratories computational study (published in the Annals of the New York Academy of Sciences and archived by both NASA's Technical Reports Server and the U.S. Department of Energy's OSTI) modeled the combined Shoemaker-Levy 9 impacts and found the total kinetic energy released was equivalent to the explosive yield of 300 gigatons of TNT, matching the figure Hancock cites.
Not a true/false call. Every claim is logged with its sources; read the exhibits below.
the comet shoemaker shoemaker levy 9 which hit jupiter in 1994 had a total calculated explosive power of 300 gigatons if you took the entire nuclear arsenal of the world today and blew it all up at once it would yield 6.4 gigatons
What the evidence says 01 / RECORD
A 1997 Sandia National Laboratories computational study (published in the Annals of the New York Academy of Sciences and archived by both NASA's Technical Reports Server and the U.S. Department of Energy's OSTI) modeled the combined Shoemaker-Levy 9 impacts and found the total kinetic energy released was equivalent to the explosive yield of 300 gigatons of TNT, matching the figure Hancock cites. That combined total obscures wide variation among the comet's fifteen individual fragment impacts, which other estimates put anywhere from roughly 10^4 to 10^8 megatons (0.01 to 100,000 gigatons) each, with the largest single fragment (G) estimated by some analyses near 6,000,000 megatons (about 6,000 gigatons), far above the combined-total figure cited. The comparison to the world's nuclear arsenal is harder to verify: published estimates of the total yield of all nuclear weapons on Earth vary by year and methodology, commonly landing somewhere between roughly 1.4 and 5+ gigatons rather than a single settled figure, so the specific 6.4-gigaton number and resulting 47x comparison cannot be confirmed against an authoritative reference. Overall, the 300-gigaton SL9 figure is a genuine, published scientific estimate, but the nuclear-arsenal benchmark used for the comparison is imprecise and not traceable to a current authoritative figure.