Physics

Scaling down the observable universe to make it fit within our moon's orbit, the Milky Way gets reduced to a village. We live close to the edge of this village, at a comfortable distance from the central marketplace, where a giant black hole is known to be lurking.  Now, this peaceful picture is brutally disturbed by an international group of astronomers who bring us the message that a black hole of at least a hundred solar masses is likely to ambush us in our own backyard.  Theta Orionis, a fuzzy star in Orion's sword harbouring a massive black hole? Ok, in true astronomical…

Alan Guth, the discoverer of cosmic inflation, gave a talk at MIT on November 1, which convinced me, a natural skeptic about these issues, that the multiverse may very well exist. Two routes to the multiverse were never to my liking. One is "Many Worlds," Hugh Everett IIIs idea that quantum events whose wave functions seem to "collapse" in our world to yield specific measurements actually never collapse but realize all other characteristics implicit in their wave functions in "other universes." Every time something happens here--of all the very large number of possibilities--all the rest of…

As I reported in a post a few days ago, the Italian sentencing of seven scientists to 6-years imprisonment for their misassessment of the risks of the population of L'Aquila, soon thereafter struck by a powerful earthquake which killed 309 and injured 2000, raised interest and disconcertment worldwide and spurred a debate which is not likely to end soon. Who is guilty ?I personally believe that the real offenders in the L'Aquila case are the politicians who put in charge a "great risks" committee which could be steered and manipulated at will, and who then put words in their mouths as they…

Outside the very large and the very small, the universe is rather easy to understand in modern times.  At the very large, we have to try and make dark matter and dark energy work.  At the very small,  quantum predictions challenge our best understanding about the nature of space and time, what we know as Einstein's theory of relativity. The implications of quantum theory have been troubling since it was invented in the early 20th Century. The problem is that quantum theory predicts bizarre behavior for particles, such as two 'entangled' particles behaving as one even when far…

Let me write here a short note -just for the record- to mention a proceedings paper I wrote for the ICFP 2012 conference. I spoke in Crete last June about the latest results of the CMS experiment, but in the meantime a lot happened -the Higgs boson discovery, just to mention one thing. So this writeup includes the new measurements of Higgs boson cross section, mass, and properties that the CMS experiment has produced since last July, as well as selected results in top and electroweak physics, searches for rare B decays, and new physics searches. The paper is a good summary of a few of the…

Human thought has led to a variety of remarkable and profound insights. Many of these insights are well established and have been embraced by a significant portion of the global population. The earth being round, the atomistic nature of matter, our unremarkable place in the universe, and us being a product of evolution, all being examples of such insights. Other insights, although unanimously embraced by experts, have a long way to go for a larger population to accept them. More than for any other subject, this holds for quantum physics. No other product of human thought is as profoundly…

Claims on the Internet live on indefinitely.  I claimed to have found a testable candidate to unify gravity with the three other fundamental forces of Nature.  Thanks to sometimes trying efforts on this Science20 blog, I now have reasons why that claim was in error.  I consider it my responsibility to unambiguously rescind the claim.  If in the future, someone starts rehashing my proposal, at least I can provide a line of defense. The word "retracted" was not used in the title since it is associated with fraud.  Editors will retract papers from journals when they…

"The problem of averaging data containing discrepant values is nicely discussed in Ref. x [...] It is difficult to develop a procedure that handles simultaneously in a reasonable way two basic types of situations: (a) data that lie apart from the main body of the data are incorrect (contain unreported errors); and (b) the opposite -itis the main body of data that is incorrect. Unfortunately, as Ref. x shows, case (b) is not infrequent [...] the choice of procedure is less significant than the initial choice of data to include or exclude." The Review of Particle Properties 2004, p.16.

Physicists at the Relativistic Heavy Ion Collider (RHIC) recently observed first glimpses of a possible boundary separating ordinary nuclear matter, composed of protons and neutrons we know today, from the odd, seething soup of their constituent quarks and gluons that permeated the early universe some 14 billion years ago. The RHIC physicists have been creating and studying this primordial quark-gluon plasma (QGP) for a while but the data they presented at the Quark Matter 2012 international conference from systematic studies varied the energy and types of colliding ions to create this new…

I had a dream. So what, we all do. Well, this was particular, because I remember all of it well, and because it involved a very interesting situation. I was at Fermilab, in an office on a top-level floor of a tall building, when a powerful earthquake hit. This was supposedly the Fermilab Wilson Hall (aka Hirise), the landmark administrative building of the Illinois Laboratory (see picture below); however, as in most dreams, reality was slightly modified. The building was not shaped like a capital "A", although it shared some distinctive characteristics with it: like the Hirise it had an…