When I was young, my main scientific interest was in astronomy, and to prove it there’s a very geeky picture of me with my telescope on display in my apartment, causing much amusement to my guests (no way will I ever allow it to be digitized, I must ensure that it never appears on the web). By the time I got to college, my interests had shifted to physics, and since that time I’ve hardly at all kept up with what is going on in astronomy. Like everyone, I’m still fascinated by the amazing pictures coming out of the field, and like most particle physicists, I’m deeply jealous of astronomers for the fact that they have a wealth of exciting new data to work with, together with promising prospects of lots more to come.
This week there’s a big meeting of the American Astronomical Society going on in Seattle, producing lots of astronomy news. Many bloggers are in attendance, including Rob Knop, Steinn Sigurdsson, Phil Plait, and C.C. Petersen. Rumors that celebrity couple Sean Carroll and Jennifer Ouellette were there turned out to be partially unfounded. Lots of press releases are being generated, including one from the University of Washington full of the usual overhyped claims about cosmic superstrings.
This week’s Science has a special issue on particle astrophysics, with lots of articles worth reading, including a nice summary of the exciting things happening in the field by Adrian Cho. He reports that many experimental particle physicists have moved into the field, partly because of the opportunities there, partly because of the difficult situation of experimental particle physics, especially in the U.S. Michael Turner is quoted explaining that the particle physicists have brought to the field some ambitious ideas, due to their habit of “thinking big”:
These are not people who are afraid to ask for big things, and they’re used to people saying yes.
An example of this is the IceCube neutrino experiment being put together under the ice in Antarctica, employing 400 researchers and costing $271 million.
Turner also has an article summarizing the situation in cosmology, where he notes that many string theorists are now pinning their hopes on making some connection to the real world in this context:
Nowhere in particle physics are the stakes higher than for string theory. If string theory is to live up to its billing as “the theory of everything” rather than, as some say, a theory of nothing, it needs a home run. Because most of its current predictions exceed the reach of terrestrial laboratories, many string theorists are pinning their hopes on a cosmological home run, such as a fundamental understanding of inflation (or a more attractive alternative), a solution to the puzzle of cosmic acceleration, or insight into the nature of the Big Bang itself.
For something truly bizarre, check out the cover story of the February issue of Astronomy magazine, entitled “What if string theory is wrong?” (mentioned earlier here). It confirms me in my opinion that I shouldn’t write about things I don’t know much about, like astronomy, since it’s by an astronomer who clearly knows very little about particle physics, especially about supersymmetry:
Supersymmetry is a mathematical principle that allows force-carrying particles, such as photons and gluons, to transform into one another. It also allows the unification of gravity with other forces because its particle, which some call the graviton, can transform into one of the other force-carriers…. If extra dimensions don’t exist, then supersymmetry doesn’t either… Without supersymmetry, some physicists have proven that the energy of empty space would be so enormous the universe would instantly collapse. Only by understanding physics beyond the standard model can we hope to understand how the vacuum works and the universe’s dark side. And only string theory appears able to serve as a reliable mathematical guide to that larger universe.
Lenny Susskind provides the usual over-the-top outrageous quote:
It is hard to find a serious paper about particle phenomenology that doesn’t in some way use the tools of superstring theory.
The author seems to believe that there’s some sort of experimental evidence of string theory and that it is just like general relativity:
While string theory is sparse on experimental validation, the situation is not so different from general relativity in its early days, when difficult mathematics made calculating a prediction extremely challenging.
and somehow thinks that string theory is the only hope for the future of physics:
Without superstring theory, we’d lose the intriguing prospects for the multiverse, with its infinite and eternal creativity in spawning new universes… More immediately, dark matter and dark energy would remain imponderable enigmas, shorn of any clues about where they come from. Astronomers can live without knowing the quantum properties of gravity. But to learn that 96 percent of the cosmos is unknowable would be a bitter pill to swallow. It would be even worse for physicists. Without a logical framework in which to pose and answer questions, our inquiries into the fundamental aspects of the physical world would devolve into semantic quibbles.
Some days I think that there’s definitely a more realistic view of string theory out there, other days I’m not so sure…
Update: It seems that Edward Witten is attending the AAS meeting, although not speaking there. See the comment from David Cobden, and Steins Sigurdsson’s blog entry from the conference Trendspotting, where he reports:
On a completely unrelated note, Ed Witten was spotted wandering the halls…
Now there is always some cosmic string or quantum cosmo thingy going on here, but what we ask (and, yes, I did actually ask), was he doing in the extrasolar planet session?
Ed likes exoplanets!
Update: Science a Gogo has an article about this, String Theory? Knot!, which uses my characterization of Susskind’s quote as “over-the-top”, but then uses the wrong quote, using something from the Astronomy magazine article which wasn’t written by Susskind.
Update: The University of Washington press release on cosmic superstrings, based upon a poster presented at the AAS meeting, has made it to Fox News (via Lubos).