In April, I wrote about my experiences with “You People”—meaning, telemarketers who pester you until you cancel a subscription to a magazine you love and have happily received for roughly a thousand years. In my case, the magazine was Discover. You see, I may be a legitimate word nerd, but I also love science in an amateurish sort of way, and Discover is perfectly pitched to teach me science without making it frustratingly hard. It was with great trepidation that I replaced my Discover subscription with Scientific American, a magazine written for a tiny bit more knowledgeable audience than I.
Scientific American is a good magazine, and as an added bonus, not once have I received an annoying phone call from a telemarketer named Bob trying to bully me into extending my subscription by a decade. I know just enough about the brain, genetics, biology, and the environment to muddle through Scientific American’s erudite articles on those topics and only feel a little stupid. At least I understand the gist of those articles, even if I can’t follow every detail. Physics, however, has never seemed so…unapproachable, opaque, and downright alien.
I enjoy reading about physics, and the physics articles in Discover were among my favorites. I’m proud to say that I read Stephen Hawkings’ book A Brief History of Time in 1990 and understood at least some of it. I felt competent to take on quantum mechanics and Einstein’s theories of relativity because there was no test at the end of the book. A few years later, I enjoyed Leon Lederman’s The God Particle, a surprisingly funny and accessible book written for non-physicists about the history of particle physics.
Scientific American, however, has shipwrecked my delusions of nerdy intelligence on the great barrier reef of complete confusion.
Please bear with me and consider this short, two-paragraph article titled ”Laser Beams That Curve,” written by Larry Greenmeier in the June 2009 Scientific American,:
“Two years ago physicists demonstrated that a laser beam traveling through the air can bend slightly if certain components are asymmetrical, forming what is called an Airy beam. Now researchers have shown that pulsed, high-intensity versions can leave curved trails of plasma. Shot out like a stack of pennies, each pulse, one centimeter wide and lasting 35 femtoseconds, passes through a glass plate that turns it into a triangular shape, in which an intense peak falls on one side of several weaker peaks. The brightest part heads in one direction, while the dimmer ones go the opposite way. (The momentum of the entire pulse remains straight, however.)
“Being extremely intense, the bright spots ionize the air behind them and leave a curved plasma stream in their wake. The self-bending beam, described in the April 10 Science, does not curve by more than the beam’s diameter, but that amount is enough to help physicists probe the structure of laser pulses.”
Greenmeier lost me at “Airy beam.” As a physics light-weight with an eye for word play, am I the only person to read this and think Fairy beam? Fairy beam makes just as much sense, plus it sounds more whimsical and fun.
Perhaps “whimsical” and “physics” simply don’t go together.
But let’s back up and ask a critical question for a physics light-weight: why is it important that “physicists probe the structure of laser pulses” in the first place? I’m willing to accept that it is important, but precisely why is not intuitively obvious. If you know the answer, please explain it in the comments in terms a reader of Discover magazine could understand.
Microsoft Word doesn’t recognize femtosecond as a word, nor does Bill Gates suggest alternate spellings. Far be it from word-loving me to rely on Bill’s wholly inadequate dictionary anyway. I checked my venerable Oxford English Dictionary, updated in 1971. (Yes, I have a copy of the OED in my home. I may only be a pretend science nerd, but I really am a word nerd.) Femtosecond is not included in that reliable tome, which leads me to suspect that a femtosecond is so short a span of time that English didn’t need a word for it until very recently, like maybe two years ago when curving laser beams suddenly became important.
For whatever reason.
With this in mind, I did a quick Google search and checked several different websites, all of which defined a femtosecond the same way, so by consensus, we may reasonably assume they are right. Remember, never, ever trust a single website for earth-shatteringly important information like this. Anyone can put anything on the World Wide Web. I should know.
According to Wikipedia (by far the most interesting definition I found),
“A femtosecond is the SI unit of time equal to 10-15 of a second. That is one quadrillionth, or one billionth of one millionth of a second. For context, a femtosecond is to a second, what a second is to about 420 million years. To give another example, one femtosecond compared to one second is like the diameter of a human hair relative to the distance between the earth and moon.”
Wow, that’s pretty fast! Notice how the analogies used in Wikipedia’s definition clarify the brevity of a femtosecond in terms even a pretend physics nerd can understand. I’m still, however, trying to figure out why Mr. Greenmeier used the metaphor of the laser pulses “shot out like a stack of pennies” to, at least theoretically, clarify his point. Who shoots pennies out in stacks? Why would they do that? What am I missing here?
The meat of the article—and I am just guessing—may be the following: “The brightest part [of the pulse] heads in one direction, while the dimmer ones go the opposite way. (The momentum of the entire pulse remains straight, however.)” What are we make of that parenthetical comment? Is it some sort of weird yin and yang of physics: different parts go in different directions, but the whole goes one way? My brain might be able to take that on faith simply because suspension of disbelief is highly developed in literature geeks, but then Greenmeier goes on to say that the plasma left in the wake of this beam is curved only by the diameter of the beam, which is still, according to Greenmeier, going straight.
Please tell me I am not the only human whose brain is hurting right now.
If you’re still reading, I thank you. Perhaps you understand why I’m on the fence about renewing Scientific American. Why would I pay for something that makes my brain hurt? Should I—perish the thought!—subscribe to Discover again, so I can get the science news I crave in an appropriately dumbed-down format? How can I return to Discover after sending them such a scathing email condemning them to the Eighth Circle of Telemarketing Hell for all eternity?
As I typed that last paragraph, a sudden inspiration struck me. I will subscribe to Discover again but will use George’s name. That’s it! If Bob the Telemarketer calls, I can simply say, “George isn’t here right now. Call back later.” Perhaps, just perhaps, if George tells Bob to take him off the call list, Bob will listen. But no matter what, Bob will be George’s problem, not mine.
I’m a genius!