Author: Matt Strassler

Family holiday here in the United States today.  That doesn’t mean no work for faculty.  Indeed this is the busiest time of year for most scientists in my field, when many chores that you don’t want to know about all come due at once, but I have managed to squeeze in a little time to try to put my posts on OPERA (the speedy-neutrino experiment) into a permanent form on the website.  I should have done this to start with, but honestly I wasn’t sure initially that OPERA’s result would survive a week of scrutiny!  Since it is now clear OPERA will be around for a while longer, I wanted to make it easier for readers to find things.

If you put your mouse over ARTICLES at the top of the page, you’ll see a whole new subsection on “Neutrinos Faster Than Light”, and underneath that other pages and subsections with more pages.  All of these are copies of posts that were posted earlier, so there’s no new information if you’ve read all those posts, but if you are new here or haven’t already looked at everything I’d written before on the subject, I hope that it will now be marginally easier to navigate.  Please let me know if you find any problems (such as broken links).  There’s also some basic information on neutrinos under “ARTICLES/Particle Physics Basics/Neutrinos”.

[If you want to know more about the OPERA experiment’s most recent result on neutrino speeds, and how it is much better than their previous one but still does not settle all the issues, click here.]

The ICARUS experiment, like the Cohen-Glashow paper on which they rely, are claiming again to “refute” the OPERA experiment on superluminal neutrinos.  (I already wrote about that here.)  I’m sympathetic, personally, but although it does provide a very strong constraint on any modification of relativity that could permit what OPERA observes, logically this does not, in my current view, constitute a refutation.   (more…)

Ok, I’ve finished an article (probably still requiring minor revisions for clarity and correctness) explaining why the recent update on the OPERA experiment is important, as well as making clear what it does and doesn’t mean.  I hope the writing is sufficiently understandable… but as I tried to write it fairly quickly, there may be some places where I have lapsed into jargon or left something out, so feel free to ask questions about points you can’t follow.

If you haven’t read about OPERA at all before, you might find this new article a little hard to follow in places.  If so, you may find useful what I’ve previously written about OPERA. Friday’s post provided a guide to my earlier OPERA posts, as well as a link to a Q&A session that many of you may find useful.  Over the next week I’ll be copying these posts over into articles that will be better organized and easier to find… so expect some Under Construction signs around for the next few days.

Couple of new articles up: we had Worlds of 1 Dimension last week, and now the article on Worlds of 2 Dimensions is ready.  Along the way I’ve addressed a natural and very common confusion about shapes and spaces that arises in the context of the Big Bang and the expanding universe (mistaking the properties of a shape with the properties of a particular way of drawing or picturing the shape.)  Coming soon (though not this week I suspect): how, if you’re a particle physicist, you can figure out that a space that appears one-dimensional is really two-dimensional… a story which will be our window into how to understand extra dimensions more generally.

Matt Strassler 11/11/11

Today is a special day — at least if you are fond of the numeral 1, or the number 11, and especially so if you’re willing to buy in to one of the oldest human pseudo-scientific pursuits: numerology.  Oh, don’t get me wrong, I love numbers and I always have.  When I was five years old I was mesmerized when my parents’ car reached 99,999.9 miles, and I think 12:34:56 on 7/8/90 is just a cool a time as anybody else does. But I do this with a sense of humor.

Unfortunately it happens that a few influential people attempt serious and consequential numerology involving the calendar — predicting disaster and convincing people to sell their homes and give away their belongings.  Now that makes me mad.  Outraged, in fact — because it’s often obvious from the way these predictions are generated that those who made them don’t understand much about the calendar, about time, about history and about astronomy or physics… and yet they speak with authority, an authority they haven’t earned and don’t deserve.

Of course the movies play this up too, making money off of people’s fear: we have an 11/11/11 horror film in store.  The prophet intones: “On the eleventh hour of the eleventh day of the eleventh month…” Well.  By the end of this article I hope you’ll wonder what he’s even talking about.  [Note added: I should have emphasized, for non-European readers, that the phrase “on the eleventh hour…” refers to the moment that it was decided, arbitrarily, that the Armistice ending the First World War should be signed. Is it not ironic that this tragically modern war was concluded at a time chosen by an ancient form of calendar numerology? Perhaps more enlightened leadership could have avoided future disasters.]

Meanwhile, we should most certainly drink to this one-one-of-a-kind moment, and as we do, let’s also remember, and enjoy, just how absurd it really is.  Let us even count the ways. (more…)

In my recent Worlds of 1 Spatial Dimension article, I wrote about various one-dimensional worlds (the Income Line, the Rainbow Line, and the Aeolian Line) — all of them involving dimensions which are not themselves physical dimensions of space. What is the distinction between a general dimension and an honest-to-goodness spatial dimension? In short, what do we mean by saying that a dimension has something to do with physical space?   Click here to learn more.