Respect my worldview!

Posted by on October 28, 2011 No comments | 2,516 views

You probably have heard that demand from various people? The idea for the post was triggered by this brief Twitter exchange on #skeptics:

Respect!The top reply there is mine, and this little exchange got me thinking. I have no idea who SnBEternally is and what their problem is. They did tell the whole of CSICON to go fuck themselves though, so there’s some animosity at least.

Anyway. So why this demand for respect? First let me clarify what I am referring to here. I do respect people’s freedom of religion, belief and speech. This is not what I’m targeting her. What I am talking about is why should I respect a given belief by default? There are numerous religious and alternative beliefs I simply cannot respect or accept because I’m a secular humanist. I don’t respect the acts of terror performed by fundamentalist Muslims. I don’t respect the hatred displayed by Christian fundamentalists towards gay people and other groups they target. I don’t respect the homoeopath who sell water and sugar for medicine to sick people. I don’t respect the anti-vaccine activist who indirectly cause great suffering for individuals and put the flock-immunity of dangerous diseases of the entire population at risk. I don’t respect the global warming denier who is too fond of their wasteful lifestyle to want to sacrifice it for the common good. I don’t respect the pope for sweeping child abuse under the rug and opposing prevention of the spreading of HIV in Africa. The list of assholes I don’t respect is long. Too long.

But let’s flip the coin and ask: Why do these people crave our respect? I don’t really give a shit if they don’t respect my world view. My world view doesn’t rely on that. It isn’t fixed. I evaluate my world view based on how well it fits with reality. Specifically I rely on scientific evidence when I make up my mind what to believe. If the evidence isn’t present I either make up my mind based on available data, or don’t form an opinion at all. I have no problem with not knowing the answer! This maybe is the key. The religious and the alternative thinking seem to demand an answer regardless of how well the answer applies to observable reality. Where did the universe come from? God made it. How does homoeopathic medicine work? Quantum mechanics does it. (As a physicist, the QM explanations for homoeopathy is complete gibberish to me). So why this craving for respect? The answer is simple I think: validation. Their world view is not self-consistent, self-evident or self-reliant, thus they need external affirmation. That is why they get so annoyed when we don’t provide this. This is also why it is a bad idea to pay too much lip service to these people. The so-called “accommodationism approach”.

Frequently Asked Questions About Time Travel

Posted by on October 17, 2011 1 comment | 3,131 views

Time for another movie review. Been a while since I did that last time. This time it’s not a new movie, but one I just discovered existed. The movie is from 2009 and is a Sci-Fi Comedy. I usually don’t find comedies very funny. Don’t know, maybe Hollywood potty or drunken humour isn’t quite my thing. This one is different though. Firstly, and probably most significantly, it is British. Most of the best comedies are, with very few exceptions.

FAQ About Time TravelFrequently Asked Questions About Time Travel is about three nerdy friends in a pub. The one guy played by Chris O’Dowd (from IT Crowd) is obsessed by time travel, and tells a story about a girl he just met who claimed to be a time agent. It’s all a bit silly really, and the guys don’t quite believe him. He doesn’t really believe the story himself it turns out. Then one of the guys needs to take a leak. When he comes back from the toilet, he has been sent forward in time. There is a time-rift in the men’s room! The story quickly gets confusing with several versions of themselves in the same pub trying to avoid running into each other. Some classic time-travel elements like a post-apocalyptic version of the city in snow-clad rubble is added to the mix, as well as evil time villains. It is all delightfully absurd, and there is just enough confusion for it to not be annoying.

Well worth watching if you’re looking for a laid back British comedy film.

Winning Hearts and Minds for Skepticism

Posted by on October 16, 2011 1 comment | 3,122 views

Great talk by Sadie Crabtree from JREF (James Randi’s Educational Foundation) from this year’s Amazing Meeting.

Sadie Crabtree – Winning Hearts and Minds for Skepticism from JREF on Vimeo.

Harddrive failure and monitoring

Posted by on October 11, 2011 1 comment | 3,084 views

Broken harddiskI have two Ubuntu servers running at home which both have large RAID volumes on them, set up via mdadm. This summer I had a total disk failure in one of my RAID5s which luckily didn’t result in data loss. Thanks you RAID5!

In any case, it caused me to write a script that logs SMART-data to a MySQL database. I also wrote an admin webpage that displays this data for me in an easy to follow way. The monitoring script itself is written in php5 and so are the admin pages. I used php5 because it is easy to communicate with MySQL from it, and it has the needed string manipulation commands. It could probably be done as easily in Python though. The script is called as a cron job every 2 hours on the servers and every hour on the desktops when they’re running. Examples of the code I’m using is attached below and includes the cron-ed script and the code generating the log output and plot.

What to look for?

Well, that is the big question. How do you know if a drive is about to fail? Google Labs has looked into this topic back in 2007 in this paper: «Failure Trends in a Large Disk Drive Population». An interesting read if you are at all concerned about harddrive failure in servers. The results for how temperature affects the lifetime and failure rate in harddrives are especially interesting. It turns out, at least in their data, that low temperature isn’t such a good thing for the drives contrary to what many people seem to assume. I have up until now been concerned that my drives get too hot, but in fact they seem to be almost overcooled the way I have things set up now.

When I wrote these scripts this summer I decided to log temperature and reallocated sector count primarily, which is what is emphasized in the log display scripts. Seems now I also should be including scan errors as well after reading that paper. The colour coding I use in the temperature plot below is loosely based on Figure 4 in the paper and reflects what seems to be the optimal operating temperature for harddrives.

Screenshots
HD-Mon Screenshot 1HD-Mon Screenshot 2HD-Mon Screenshot 3
Screenshot 1: The overview page.
Screenshot 2: Details of one of the RAID-drives.
Screenshot 3: Details of one of the drives with reallocated sectors.

Code

The php source code I wrote is available in this file: hd-mon.tar.gz

It is specifically designed to work with my setup and hardware and probably isn’t universal, but it gives an idea of how I set it up. There are probably better ways of doing this though. I just call shell commands from php and parse the returned text-string and do simple search on it and input the data into a MySQL database.

I also included php-snippets showing how the admin page is generated. These are not standalone php files, they need to be wrapped in a template. However they reproduce what is seen in the screenshots above.

Packages needed for these scripts to run:

  • php5-cli for the php5 command line.
  • mysql-client, php5-mysql for the database connection.
  • smartctl to access the SMART-data.
  • mdadm to access RAID-data (assuming you use mdadm for RAIDs in the first place)

All are available in the Ubuntu repository.

Neutrinos and speed of light

Posted by on September 23, 2011 3 comments | 3,704 views

I just finished watching the 2 hour long webcast from CERN about the very surprising results that neutrinos have been measured with a velocity greater than the speed of light by a couple of thousandths of percent. If this turns out to be correct, i.e. can be confirmed by other neutrino experiments, it may have great implications for our current understanding of physics. It may not necessarily prove current physics wrong, it may just put a limit on the range of current physics. I.e. there may be new theories that will explain these results without having to chuck “old physics” in the bin in the same way as Einstein’s physics did not replace Newtonian physics as such, but expanded on it. That is after all what the LHC was built for.

So what are the results from OPERA? Well in a nutshell from the conclusion of the presentation:

Conclusion 1Basically what this says is that the neutrinos arrived at the detector some 730 km from the point they were created 60.7 nanoseconds before a photon would have arrived had it undertaken the same trip.

The big question is of course: are the measurements correct? The big points here are the synchronization of the clocks at both locations and the accurate measurement of the distance between them. The paper from arxiv.org linked below describes in detail how these are calibrated and how accurate they are. Another point, and this is probably where the error is made, is how they fit the plots of the arriving neutrinos. The 60 nanosecond shift produces the best fit, but I don’t think this looks very convincing (as discussed in the link to Résonaances below).

Other previous measurements of neutrinos from supernovae have not shown this result. This question was asked in the Q&A session after the presentation, and the answer given was that these are high-energy neutrinos at 17 GeV. Supernova-neutrinos are not, they’re in the 10 MeV range, so a factor of a thousand less. As you may know, nature does a lot more funky stuff at high energy than at low energy, another reason for building machines like the LHC. What needs to happen now is to have some of the other experiments try to reproduce this result at the same energies.

The article from NewScientist below also gives a possible explanation for this phenomenon using extra dimensions.

Regardless, time will show if this result is real or a fluke of some sort. If it turns out to be real, it requires explanation, and that’s where all the fun begins … for physicists at least!

Further reading:

Other comments:

Updated 24.09.2011