[The following is my review of The Infinity Puzzle: Quantum Field Theory and the Hunt for an Orderly Universe, by Frank Close. It appeared in the July 2012 issue of Physics World.]
Since it opened for business a couple of years back, CERN’s Large Hadron Collider (LHC) has been confirming the validity of the Standard Model of particle physics to ever greater precision and accuracy. In the process, it has been causing ever-greater frustration among theorists, many of whom had hoped that the collider would quickly uncover new physics. Given the Standard Model’s current robust status, it is easy to forget that during the 20th century, its theoretical bedrock – quantum field theory – was left for dead at least twice by its own creators. Frank Close’s book The Infinity Puzzle contains a timely reminder of these near-death experiences.
The first convincing quantum description of a field, the reader learns, arrived in 1928, in the form of Paul Dirac’s theory of the electron and of the electromagnetic interaction. Dirac’s equations had some indisputable successes: they fitted spectroscopic data, explained photons and quantum spin, and even foresaw the existence of the positron. But his theory seemed incomplete. If a field is supposed to be a “thing” with a quantum life of its own, then it surely should interact with the electron that generated it – yet Dirac’s equations seemed unable to account for such “self-interaction.” Theorists’ fears were confirmed in 1947 when Willis Lamb announced that he had found a small deviation from the predictions of Dirac’s theory in the hydrogen spectrum.
Continue reading at Physics World
Speeding toward interstellar space, NASA’s twin Voyager probes have now truly peered outside the solar system—and they’ve seen something no human has glimpsed before.
According to a new study, the two spacecraft have detected a type of ultraviolet light from other regions of our Milky Way galaxy that had previously been all but invisible due to the sun’s glow.
“People have tried to make this measurement from Earth orbit, unsuccessfully,” said veteran Voyager scientist Bill Sandel of the University of Arizona in Tucson.
The light, a wavelength of ultraviolet called Lyman-alpha radiation, is emitted by hydrogen atoms as they cool down. The radiation is especially intense in stellar nurseries where lots of new stars are forming.
Read the rest of my story at National Geographic News.
My two latest posts at Degrees of Freedom describe how the universe acts as a giant magnifying lens, so that very distant galaxies appear larger in the sky than closer ones, in a reversal of the usual laws of perspective.
The Cosmic Magnifying Lens describes the phenomenon (check out the videos!), and
A Step-by-Step Guide to Cosmology’s Best-Kept Secret explains the physics behind it, which has to do with stuff receding from us faster than the speed of light. Because of the expansion of the universe, distant objects can indeed be superluminal.
Mariastella Gelmini, Italy’s Minister of Education, University and Research, made an embarassing statement about the annoucement made last month by physicists on the OPERA collaboration, in which she said that Italy had contributed to the construction of a tunnel between CERN and the national underground laboratories called Laboratori Nazionali del Gran Sasso. Of course, there is no such tunnel. The ministry now quietly took the statement offline. For the record, I am posting the full text of the statement below.
Roma, 23 settembre 2011
Dichiarazione del ministro Mariastella Gelmini “La scoperta del Cern di Ginevra e dell’Istituto Nazionale di Fisica Nucleare è un avvenimento scientifico di fondamentale importanza.”
Rivolgo il mio plauso e le mie più sentite congratulazioni agli autori di un esperimento storico. Sono profondamente grata a tutti i ricercatori italiani che hanno contribuito a questo evento che cambierà il volto della fisica moderna. Il superamento della velocità della luce è una vittoria epocale per la ricerca scientifica di tutto il mondo.
Alla costruzione del tunnel tra il Cern ed i laboratori del Gran Sasso, attraverso il quale si è svolto l’esperimento, l’Italia ha contribuito con uno stanziamento oggi stimabile intorno ai 45 milioni di euro.
Inoltre, oggi l’Italia sostiene il Cern con assoluta convinzione, con un contributo di oltre 80 milioni di euro l’anno e gli eventi che stiamo vivendo ci confermano che si tratta di una scelta giusta e lungimirante”.
|Emi Kasai/Scientific American
|Martin Gardner’s Mathematical Games column was often the cover story. Those were the days.
I started a new math and physics blog called Degrees of Freedom as part of ScientificAmerican.com’s new blog network, managed by Bora Zivcovic.
In the introductory post I talk about how I envision the blog and what it will be covering. Hyperlinks throughout the post bring you to past examples of my writing on math and physics.
In the first real post I describe a way of visualizing the cosmic microwave background (also known as the “afterglow of the big bang”) that I am sure is familiar to some cosmologists but that I have never seen written or heard described anywhere.
In the same post, I also point out that the sky used to be red before it turned black. That is also something I have not seen mentioned elsewhere.
I am not retiring sciencewriter.org though. I will still be posting here, either to add more context to articles I wrote (including posts on Degrees of Freedom itself), or to talk about things that would be off-topic there (including the occasional shameless self promotion).
As always, you can get updates by following me on Twitter at @dcastelvecchi.