But what if they are faster than light? : Quantum Diaries

But until we get the results of OPERA’s proposed studies we can’t say for sure that their measurement is right or wrong. Suppose that they reduce the lead time of the neutrinos from 60ns to 40ns. That would still be a problem for special relativity! So let’s investigate how we can get faster than light neutrinos in special relativity, before we no longer have the luxury of an exciting result to play with.

AFAICT, no one knows if the OPERA corrections for the cable problem will drop the CERN neutrinos below the speed of light. This post takes a fun look at how it could be that photons might not travel as fast as is physically possible, and why neutrinos might.


Cosmologists Try to Explain a Universe Springing From Nothing – NYTimes.com

There is a deeper nothing in which even the laws of physics are absent. Where do the laws come from? Are they born with the universe, or is the universe born in accordance with them? Here Dr. Krauss, unhappily in my view, resorts to the newest and most controversial toy in the cosmologist’s toolbox: the multiverse, a nearly infinite assemblage of universes, each with its own randomly determined rules, particles and forces, that represent solutions to the basic equations of string theory — the alleged theory of everything, or perhaps, as wags say, anything.

This is deeply unsatisfying, for reasons I’ll get to in a minute. Dr. Krauss is following in the tradition of Pierre-Simon Laplace:

Laplace went in state to Napoleon to present a copy of his work, and the following account of the interview is well authenticated, and so characteristic of all the parties concerned that I quote it in full. Someone had told Napoleon that the book contained no mention of the name of God; Napoleon, who was fond of putting embarrassing questions, received it with the remark, ‘M. Laplace, they tell me you have written this large book on the system of the universe, and have never even mentioned its Creator.’ Laplace, who, though the most supple of politicians, was as stiff as a martyr on every point of his philosophy, drew himself up and answered bluntly, Je n’avais pas besoin de cette hypothèse-là. (“I had no need of that hypothesis.”) Napoleon, greatly amused, told this reply to Lagrange, who exclaimed, Ah! c’est une belle hypothèse; ça explique beaucoup de choses. (“Ah, it is a fine hypothesis; it explains many things.”)

The deeply unsatisfying part is hinted at in the NYT article: “But even the multiverse is not totally lawless, as Dr. Krauss acknowledged. We are not quite there yet. At the very least, there would still be the string equations and those quantum principles that undergird them.

Ah yes, because if we have nothing at all, we have nothing at all. Nothing that can fluctuate, nothing that describes strings, not even the abstract entities of mathematics, such as randomness. We just have… nothing. No existence of any kind, abstract or concrete. How can existence emerge from nonexistence? This puzzle is in fact a riddle wrapped in an mystery inside an enigma. Lengthening the chain from the Multiverse of today to Nothing At All doesn’t remove the paradox.

The Mathematician’s Valentine


Roses are red.
Violets are approximately blue.
A paracompact manifold with a Lorentzian metric can be a spacetime,
if it has dimension greater than or equal to two.

S. C. Kavassalis

My personal favorite is the Serpenski heart card pop-up.