Eh, so too good to be true.

Yeah, it was quite a compelling story, and it's at least a genuinely beautiful and intriguing tablet. The author Hempsell does have some talent though, in seemingly getting a reputable university to publish his book... I'm thinking he was quite canny in finding this attractive untranslated tablet with little else written about it, and then employing enough knowledge about a combination of different subjects (ancient Sumerian, asteroid orbits, Alpine geology) that no single reviewer was able or motivated to properly evaluate all the arguments. Or he just had a friend at the press.