I attended yesterday some presentations on diverse topics of current research. This sessions were intended for the students of an introductory course in modern physics and I presented a little talk about baryogenesis, you can get it here (in spanish), as the course didn't cover cosmology in its (large) list of topics I actually spent a large fraction of the talk in some elementary concepts like the Friedmann equation and the critical density.

One of the talks was actually very intersting for many reasons, it was a 6d extension of the old Kaluza-Klein theory that was worked by a local faculty member some years ago when he was at Moscow State University. The intersting stuff is that he claimed that the model could reproduce the Glashow-Salam-Weinberg theory of electroweak interactions, unfortunately the talk was pressented by a student that was unable to give absolutely any detail of how they arrived at that conclusion (I have requested the original author a copy of the article, I'll post it when I have it), but the most interesting result was that they derived that some constants were changing in time (this is not a really new idea) and among the changing constants was e, the unit of electric charge.

Although it would be an amazing discovery this simply looks wrong, changing the value of e over time would change the fine structure constant (α ≡ e^2/h bar c ≈ 1/137). However there have been many attempts to check if α is constant and any of them have found nothing, you can look at a recent one here (the published article is here). Look at Sean Carroll's entry on changing constants (in his case it is the ratio between the mases of the proton and electron) here.

At the end of my talk I was bombarded by questions that sounded to me like the stationary universe: the idea that the universe looks the same in time, this needs some matter creation mechanism (otherwise the density would change in time). I actually went to explain that practically anyone in the astrophysical community believes in this kind of theories, that CBR really looks like blackbody radiation and it lacks the polarization one would expect if CBR is light from ancient stars which has been scattered by galactic dust (the usual explantion of CBR in steady state theories), and that we have a really big body of evidence that suggests that indeed the density is changing some members of the audience still seemed to prefer to just ignore the bulk of experimental evidence.

I don't want to state a debate here (there are so many intersting debates at Peter Woit's blog "Not even wrong"), but it really concerns me that a (rather small, to be honest) fraction of the theoretical community is so distanced from the experiments.

## Tuesday, June 13, 2006

## Thursday, June 01, 2006

### New Ubuntu release

The latest version of the popular linux distribution Ubuntu has been released today. I don't really find necessary to post a review here because there are many excellent reviews in Distrowatch, but if you need some scientific software running in linux keep reading.

In observational astronomy the most important software package is undoubtly IRAF, you can get it very easily following this instructions, the other famous astronomy package is the now dead Starlink, the debian version of it runs nicely in Ubuntu.

Adding additional repositories will allow you to install lots of scientific apps easily using synaptic, among them are the numerical libraries gsl and scipy, the matlab clone GNU Octave, fortran compilers, latex editors like Lyx and Kile, computer algebra systems like maxima and yacas, the TexMacs interface, the fast numerical app yorick, R, Cernlib, plotting sotware like GNUplot and kst, QCad and many other apps.

In observational astronomy the most important software package is undoubtly IRAF, you can get it very easily following this instructions, the other famous astronomy package is the now dead Starlink, the debian version of it runs nicely in Ubuntu.

Adding additional repositories will allow you to install lots of scientific apps easily using synaptic, among them are the numerical libraries gsl and scipy, the matlab clone GNU Octave, fortran compilers, latex editors like Lyx and Kile, computer algebra systems like maxima and yacas, the TexMacs interface, the fast numerical app yorick, R, Cernlib, plotting sotware like GNUplot and kst, QCad and many other apps.

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