The Internet is a sort of cyberspace limbo where myths in the history of science, which have been debunked a long time ago, keep popping up on social media as #histsci zombies, the history of science undead. One such that has popped up to haunt me several times in recent weeks is the claim that Johannes Kepler murdered Tycho Brahe. This claim was at best ludicrous and, having been thoroughly debunked, is now just pathetic but continues to ghost through cyberspace as a #histsci zombie. Where does it come from, who put it into the world and did it ever have any validity?

After protracted negotiations and a return to Graz to fetch his family Johannes Kepler began to work with Tycho Brahe in Prague as his assistant in late 1600, not as his student as is often falsely stated. In September 1601, Tycho managed to negotiate an official position for Kepler at the Imperial Court of the German Emperor Rudolph II. Their partnership was however short lived, as Tycho died 24 October 1601. According to Kepler’s account Tycho had retained his urine during a banquet eleven days earlier, so as not to breach etiquette by leaving the table. Upon returning home he was unable to urinate, fell ill and falling into delirium died, apparently of some sort of urinary infection. This was the state of play in 1601 and remained unchanged until 1901.

In 1901 Tycho’s body was exhumed and an autopsy carried out that failed to establish a cause of death. However when the corpse was reburied a sample of his beard hair was retained. In 1990 this hair sample was analysed and found to contain abnormally high levels of mercury, which led to the speculation that Tycho had died of mercury poisoning. At this point there was no real suspicion of murder but more speculation about an accidental mercury poisoning. Tycho was a Paracelsian pharmacist, who along with his observatory on Hven ran a pharmacy that produced various medical remedies. The speculation was that he had either poisoned himself whilst working with mercury, a not uncommon problem amongst pharmacists in the Early Modern period when mercury was used extensively in medicines, or that he had poisoned himself by taking one of his own mercury containing remedies.

The first real accusations that Tycho had been murdered, that is poisoned by another person, came with the publication in 2004 of Joshua & Anne-Lee Gilder’s book Heavenly Intrigue: Johannes Kepler, Tycho Brahe, and the Murder Behind One of History’s Greatest Scientific Discoveries. Put simply the Gilders claimed that Kepler had poisoned Tycho to gain access to his astronomical data. The first part of their book, in which they outline the lives of Tycho and Kepler is actually well researched and well written but it’s when they come to the cause of Tycho’s death the book goes of the rails.

The Gilder’s build a chain of speculative, unsubstantiated, circumstantial evidence leading to their conclusions that Tycho was murdered and Johannes Kepler did the evil deed. Any able defence lawyer or competent historian of science could dismantle the Gilder’s rickety and highly dubious chain of evidence without too much effort leading to a full acquittal of the accused. Unfortunately most book reviewers are neither lawyers nor historians of science and the popular press reviewers jumped on the book and swallowed the Gilder’s arguments hook, line and sinker. The result was that Kepler went from being a hero of the scientific revolution to being a perfidious murderer, almost overnight.

Fascinatingly, the furore created by the popular press led to an international team of experts being granted permission to exhume Tycho’s corpse and to carry out yet another autopsy. The noble Dane would not be allowed to rest in peace. This was duly done in 2010 and the corpse, or what was left of it, was subjected to a battery of scientific tests. All of this activity led to the popular science press publishing a cart load of articles, many of them on the Internet, asking if Kepler had indeed poisoned Tycho most of them skewing their articles strongly in the direction of a guilty verdict.

The international team of archaeologists, forensic anthropologists, pathologists and whoever took their time but in 2012 they finally published their results. There was not enough mercury present in the samples to have caused mercury poisoning and there were no other poison found in any quantities whatsoever. Tycho was not poisoned by Johannes Kepler or anybody else for that matter. A second independent team re-analysed the beard hairs taken from the corpse in 1901 and confirmed that there was not enough mercury present to have caused mercury poisoning.

The press outlets both popular and scientific that had trumpeted the Gilder’s highly dubious claims out into the world did not apply the same enthusiasm to reporting the negative results of the autopsy. Those lengthy articles in the Internet claiming, implying, insinuating or suggesting that Kepler had done for his employer were not updated, amended or corrected to reflect the truth and the Gilder’s book was not withdrawn from the market or consigned to the wastepaper basket, where it very definitely belongs. Below is part of the sales pitch for that book taken just a couple of hours ago from Amazon.com:

But that is only half the story. Based on recent forensic evidence (analyzed here for the first time) and original research into medieval and Renaissance alchemy—all buttressed by in-depth interviews with leading historians, scientists, and medical specialists—the authors have put together shocking and compelling evidence that Tycho Brahe did not die of natural causes, as has been believed for four hundred years. He was systematically poisoned—most likely by his assistant, Johannes Kepler.

An epic tale of murder and scientific discovery, Heavenly Intrigue reveals the dark side of one of history’s most brilliant minds and tells the story of court politics, personal intrigue, and superstition that surrounded the protean invention of two great astronomers and their quest to find truth and beauty in the heavens above.

The result of all this is that historian of astronomy of the Early Modern period are forced to indulge in a game of historical Whac-A-Mole every time that somebody stumbles across one of those articles in the Internet and starts broadcasting on Twitter, Facebook or wherever that Johannes Kepler murdered Tycho Brahe.