The history of science shows some wrong theories being accepted by leading scholars for long periods of time. Ptolemaic astronomy, unquestioned for over 1200 years, is a prime example. Not all examples are old, though. In modern times as well, scientists are finding that theories unquestioned for decades, even centuries, were wrong. That being so, what confidence can we have that today’s scientific beliefs will stand the test of time for the next decade or century? A recent spate of science articles shows some long-held theories being questioned – others being tossed overboard.
- Newt for precedent: For 250 years, scientists believed there was a limit to how many times an amphibian could regenerate tissues, such as limbs and eyes. This week, PhysOrg posted a press release with the headline, “Overturning 250 years of scientific theory: Age, repeated injury do not affect newt regeneration.” Sure enough, “Scientists have been wrong for 250 years about a fundamental aspect of tissue regeneration, according to a University of Dayton biologist who says his recent discovery is good news for humans.” Dr. Panagiotis Tsonis decided to test the old belief with experiments. He found that even after 18 times, a newt’s regenerated eye lens was just as good as the first. “His findings overturn long-accepted theories proposed by regeneration scientists that age and repeated amputation negatively affect regeneration.” New Scientist also wrote about this scientific upset.
- Nuclear winter: In 1983, Carl Sagan and other scientists proclaimed, with the authority of science, that a nuclear war would cast the planet into decades of darkness and cold. Sagan scared government officials with the prospect of “the extinction of Homo sapiens”. This week, Russell Seitz in a letter to Nature claimed, “Nuclear winter was and is debatable.” He quoted skeptical scientists at the time who “regarded this apocalyptic prediction as an exercise in mythology.” One from MIT said, “Nuclear winter is the worst example of the misrepresentation of science to the public in my memory.” The skeptics, though, were outshouted by a media sympathetic to Sagan. Dramatic visualizations on TV of the last humans freezing to death in the dark clinched the story.
Many today still remember the catchy phrase nuclear winter and assume it has a scientific basis, but Seitz says, “This potential climate disaster, popularized in Science in 1983, rested on the output of a one-dimensional model that was later shown to overestimate the smoke a nuclear holocaust might engender. More refined estimates, combined with advanced three-dimensional models… have dramatically reduced the extent and severity of the projected cooling” – so much so, that the worst-case scenario has fallen “to numbers so unseasonably small as to call the very term ‘nuclear winter’ into question.” This doesn’t mean, of course, that a nuclear bomb wouldn’t ruin your whole day, but it might do in Homo sapiens with fire, not ice….
Continue Reading on crev.info