In tonight’s episode, Sheldon is angry. Or maybe it is just me. Some European researchers appeared to beat Sheldon to the discovery of magnetic monopoles. In real life. And they are not even particle physicists. Now Sheldon could be upset, but he can’t cry foul if he were scooped by a team that “got there first” with a technique that was better, or at least faster. There is only one problem.
At the end of last season, Sheldon led the gang on a months-long expedition to the Arctic to find the magnetic monopoles predicted by string theory. The team returned in the season premiere, after a long ordeal, but like all such experiments before them, without catching any magnetic monopoles. Then things took a strange turn for all of us.
In between the season premier’s taping date (August 11, 2009) and its air date (September 21, 2009) an article appeared on September 3 in the prestigious journal Science claiming discovery of magnetic monopoles. The equally prestigious journal Nature immediately ran a news summary, “Overwhelming evidence for monopoles: Multiple experiments reveal materials with single points of north and south“.
Worse still, the researchers interviewed for the Nature article were taunting Sheldon in public:
People have been looking for monopoles in cosmic rays and particle accelerators — even Moon rocks,” says Jonathan Morris, a researcher at the Helmholtz Centre for Materials and Energy in Berlin.
Instead, these researchers claimed, they found monopoles in small magnetic crystals “the size of an ear plug”. Boy, Sheldon and everyone else searching for monopoles in cosmic rays and at accelerators must have been pretty stupid to be looking in all those wrong places.
But here’s the “only one problem”. For every North magnetic pole the researchers created in their small crystal samples, another magnetic pole, the South pole could always be found. As Sheldon describes to Ira Flatow on National Public Radio’s Science Friday, “mono-” means one in Greek (“di-” being two.) These samples always had two. Sure, to have called them “monopoles” is only off by one, so maybe the editors of Nature will claim they were close enough. But one versus two makes all the difference, between revolutionary “monopoles” and mundane “dipoles”. They experiment reported simply did not discover magnetic monopoles.
The experiment reported in Science was a tour de force. The experimenters did a beautiful job of separating the “North” and “South” poles by an enormous distance (nanometers, or billionths of a meter, which only a physicist could call “enormous”) in the materials, called spin ices. So-called because the arrangments of spins is similar to that of hydrogen atoms in frozen water. The experimenters created long tubes of magnetic fields, like spaghetti, whose ends behaved just like magnetic monopoles. However, spaghetti has two ends. They had created two objects like monopoles with opposite charge….in other words, a dipole. Now each of these quasi-monopoles is still interesting. It creates an anomaly in the crystal called a singularity. The researchers measured and quantified much about the behavior of these singularities by scattering neutrons off of their samples. Condensed matter theorists had developed interesting models about how such singularities would behave, and this experiment provides much needed data on the topic.
My only beef, and probably Sheldon’s too, is that overselling results by the media has consequences. The public naturally comes away thinking a discovery of a completely different magnitude has been made. What happens if one day Sheldon or someone else discovers a real magnetic monopole? Physicists would have cried wolf too many times.
Now perhaps the media went farther than the researchers claimed. For example, when my Ph.D. experiment, the CDF detector at Fermilab, announced evidence for the top quark in 1994, the New York Times said the final element of matter had been discovered (NYT 4/26/94). Well every single one of us knew full-well that at least the tau-neutrino and probably many other particles had yet to be discovered. Sad to say, this happens often, and consumers of the science media should take reports of major discoveries with a healthy dose of skepticism. (Extrapolating, it makes me wonder how much we should believe of what reporters say about politics or world events.)
Thankfully there are exceptions. Sometimes after an interview reporters come back to me with their near-final draft and ask for comments. Those reporters get it right. I heard from someone that went to journalism school that they discourage reporters from going back to the interviewees for a final check, to promote impartiality. But what’s the point of of impartiality on a news item that is not even correct?
So perhaps the same happened to the authors here. I checked the original article and right in the first paragraph they are careful to state that they have created objects “resembling” monopoles. They say that they “look like” magnetic monopoles. While they never explicitly stated that these were not real monopoles, I think the researchers have done an honest job in the original article. It is in the news summaries, such as the one linked above, and its echoes throughout the news world, where things got carried away.
Perhaps after listening to Sheldon’s interview on NPR’s Science Friday, the journalists who wrote the news summaries confusing this experimental observation with true monopoles will post a clarification. Sheldon is waiting.