Fewer and fewer science writers these days are credulous enough to keep promoting string theory, but there still are some around willing to keep writing overhyped stories about how theorists have finally found a way to get some sort of prediction of something observable out of string theory. One of these is Tom Siegfried, who has a new article in Science magazine entitled A Cosmic-Scale Test for String Theory? which reports that “some string theorists now believe they’ve found a way to make superstrings observable.”
Siegfried reports for Science from PASCOS 2006, where he finds two results worth writing articles about. One of these is the recent preliminary neutrino oscillation results from MINOS, which certainly are worth reporting, but the second is the cosmic superstring hype that has been around for nearly three years now, and which I’ve commented on in various places, including here and here. The hype surrounding this topic first got seriously going with a press release from UCSB more than two years ago, in which Polchinski claimed that cosmic superstrings were “potentially visible over the next year or two” at LIGO. Now that this time period is up, the hype has to be modified, and Siegfried informs us that:
LIGO may not be sensitive enough to detect them, but a planned set of three space-based gravitational wave detectors known as LISA would be a good bet.
As is always the case with string theory, there aren’t any real predictions here. The hype is based on the fact that, among the nearly infinitely complicated string theory models people have studied, it is in principle possible to come up with ones in which superstrings created in the early universe would expand to a very large “cosmic” scale and thus be observable. They would show up in various astronomical observations, but no one has yet seen the slightest evidence of such a thing. One can claim that it is logically possible that such things exist, with exactly the right properties to have escaped observation so far, but to be visible to the LISA experiment if it really does manage to get funded and operate sometime in the next decade. While this is logically possible, saying that “it would be a good bet” is pretty absurd; I doubt that any physicist would be willing to put money on this unless given very high odds.
The hype surrounding cosmic superstrings tends to completely confuse the kind of cosmic strings that occur as defects in the Higgs field in some GUT models (which have been studied for about 30 years now) with the kind that are supposed to come from elementary strings. Siegfried’s article includes a graphic purporting to show a “network of enormous ‘superstrings'”. As far as I can tell, this is nonsense, since the same graphic occurs here, in an article from 2000, long before the “cosmic superstrings”, where it is described as showing “cosmic strings form[ed] from a random initial distribution of phases of a hypothetical field called a Higgs field.”
Oh, and the fact that I think this is a pretty sad example of bad science reporting by someone completely taken in by the string theory hype machine has nothing to do with the fact that its author recently wrote an extremely hostile, unfair and inaccurate review of my book…
Update: For an example of the kind of misinformation spread by stories like this, see this blog entry by another science journalist, over at Seed’s ScienceBlogs.