Optics basics: What is a wave? Part IV: Important quantities

Posted on December 12, 2007 by skullsinthestars

To conclude my discussion of optics basics, I want to introduce some of the standard quantities used to describe waves and wave propagation. Unlike previous ‘basics’ posts, this one will necessarily deal with a little bit of algebra and perhaps a little trigonometry.

The simplest wave to deal with from a theoretical point of view is a harmonic wave, one which consists of an infinite sequence of regularly spaced ‘ups and downs’. A portion of such a wave traveling to the right on an extremely long string would appear as:

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Posted in Optics, Optics basics | Tagged , | 6 Comments

Night of the Meteorites!

Posted on December 12, 2007 by skullsinthestars

For those interested in astronomy and cool space phenomena, there’s a treat coming up tomorrow night: one of the best meteor showers of the year will have its peak on December 13th (h/t Americablog).  The Geminid meteor shower will be best seen from Central Asia to Alaska, but North America should still get a pretty good show.

As long as it doesn’t bring with it a cheesy 80s-style apocalypse, I’ll be excited to see if I can see anything.

(And, yes, I know the difference between a meteorite and a comet.  Don’t ruin my joke.)

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Optics basics: What is a wave? Part III: Diffraction

Posted on December 10, 2007 by skullsinthestars

In part II of my series on ‘What is a wave?’, I addressed one of the two most significant behaviors of waves, namely interference, the ability of a wave to ‘interact’ with itself. The second behavior of waves which is extremely significant is diffraction, and we will address it in this post.

Diffraction may be broadly defined as the tendency of a wave traveling in two or more dimensions to spread out as it propagates. The most significant consequence of this spreading is the ability of waves to ‘bend around corners’ when faced with an obstacle. We all have experienced the diffraction of sound waves: if you and a friend stand on opposite sides of a large building (say a farmhouse) in the middle of an open field, you will be able to talk to each other even though there is no direct ‘line of sight’ between you and your friend, and no ability for the sound waves to reflect off of intermediate surfaces. The sound waves wrap around (diffract around) the outside of the farmhouse, allowing communication.

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Posted in Optics, Optics basics | Tagged , | 10 Comments

Clive Barker’s Mister B. Gone

Posted on December 9, 2007 by skullsinthestars

Clive Barker is back with a new novel!  Mister B. Gone is now available in a lovely hardcover edition.  The dust jacket labels it a ‘tour de force of the supernatural.’  That may be a bit of an exaggeration, but Clive Barker has written a nice, compact, unconventional horror novel.

The hardcover edition itself is lovely, as I have said: it has an antiquated-looking dust jacket  combined with an ornate lining and artificially yellowed pages.  This is all part of the book’s premise: you are not holding a mass-produced novel written in 2007, but rather a unique volume put together in the year 1438, which contains the bound soul of a demon who will speak directly to you through the course of the reading, growing more angry and sinister as you progress.

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Posted in Horror | Tagged | 1 Comment

An interesting week…

Posted on December 7, 2007 by skullsinthestars

Well, it’s been quite a week. My blog posts critiquing Mr. Relativity Denialist have been visited by an amazing number of people, making my blog stats look like a delta function, my postdoc advisor was in town to give a talk and plan some new research with me (as well as go out for drinks), and I officially received a book contract from a good scientific publisher, meaning that within a little over a year, I’ll probably be published!

On the other hand, I lost a credit card this week. Fortunately, I canceled it before anything bad happened. Amusingly, though, when I called the company to notify them of the loss, I first received a recorded message telling me that my limit had been raised! That was about the last thing I wanted to hear with a card on the loose…

Next week I’m going to get back to my ‘Optics basics’ posts; I’ve already written a large part of my diffraction post.

Posted in Personal | 2 Comments

Relativity Denialist: A perfect example of “Not even wrong” (though he’s actually wrong, too) Part II

Posted on December 6, 2007 by skullsinthestars

Halfway through writing my previous post on Mr. Relativity Denier I realized there was way too much stuff to criticize in a single blog post. I had to meet a real scientist for dinner, so I took a break and thought I’d come back and analyze some of the more specific ‘claims’ presented in this shambles of logical fallacies and, yes, pseudoscience.

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Posted in ... the Hell?, Physics | Tagged , | 8 Comments

Relativity Denialist: A perfect example of “Not even wrong” (though he’s actually wrong, too)

Posted on December 5, 2007 by skullsinthestars

Note: Wow, this post has gotten a lot of traffic!  I feel duty-bound to note, though, that mine is not the only analysis of this relativity crackpot: Blake Stacey at Science After Sunclipse has been compiling a list of some of the other responses, each of which has something a little different to say.   Everyone is in agreement that the crackpot is wrong, wrong, wrong!

I’ve talked a little bit about relativity denialists, for example in the form of biblical geocentrists. Relativity theory is a theory of both surreal consequences and profound implications, and it’s not surprising that there are people out there that just don’t like it. Not surprising, but completely annoying.

PZ Myers at Pharyngula, in an attempt to spread the misery and irritation that biologists experience in the form of evolution denialists, has posted a link to an article by a “mathematician graduate” who attempts to argue that Einstein’s theory is more metaphysics than physics. Instead, he demonstrates a complete lack of understanding of physics (and mathematics), and demonstrates perfectly what the phrase “Not even wrong” means.

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Posted in ... the Hell?, Physics | Tagged , | 8 Comments

Making light follow a curve (updated)

Posted on December 4, 2007 by skullsinthestars

I was sent a link today to an interesting article about some research done at the University of Central Florida. Researchers have concocted a class of optical beams which appear to follow a curved trajectory in free space propagation. A theoretical picture of the behavior of such a light field on propagation is shown below:

The horizontal axis represents the transverse profile of the beam, while the vertical axis represents the propagation direction. Lighter colors, of course, indicate a brighter field. As one can see, the brightest beam in the wavefield, as well as all the secondary ones to its left, are curving to the right as they propagate!

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Posted in Optics, Science news | Tagged , | 7 Comments

Something to make your favorite creationist’s head explode

Posted on December 2, 2007 by skullsinthestars

I was wandering through my local craft store the other day and came across the following interesting artifact:

It’s a miniature natural history museum, complete with prehistoric man and dinosaurs galore. The kicker is that it’s a miniature for under the Christmas tree, from the Lemax collection. There’s also an exhibit on the dodo, in the lower right.

Mixing Christmas and prehistoric evolutionary evidence? That’s enough to make any creationist gag. I’m thinking of getting one for the home…

Posted in Silliness | Tagged , | 2 Comments

The crappiest horror movie endings I can think of… and some of the best!

Posted on December 1, 2007 by skullsinthestars

My recent rant about the ending of The Mist made me start thinking of various horror films which have really atrocious endings. Horror films seem particularly susceptible to crappy endings, as many writers and directors think that all horror movies have to end with a ‘shocker’ or an ‘ironic twist’. If well-planned, such an ending can be magnificent, but more often than not it ends up being a complete non sequitur. (Think about the ending to the remade Planet of the Apes.) A really goofy ending can also ruin what otherwise might have been a perfectly nice film. I decided to dredge my brain for examples of some of the worst horror movie endings. I’ll give a list, and then a spoiler-laden explanation of why I think they’re terrible. To clear the awful taste out of our mouths afterwards, I’ll list a few of my favorite horror endings… feel free to add your own suggestions in the comments!

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Posted in Entertainment, Horror | Tagged , | 23 Comments