Faster than a speeding bullet

Perhaps not the most wisely chosen title for this Scientific American newsbite, but very cool research: “Ultra High Speed Camera Records at Speed of Light

They have built a high-speed camera with a high-enough frame rate that they were able to watch a pulse of laser light traveling through a Coke bottle in slow motion. (Pause for a moment to watch this video, for it’s really impressive. I’ve linked to the juicy part.)

You should never read Youtube comments, but on this video, people are actually asking good questions, albeit with the usual Internet rudeness. There are two very confusing things said in the video and article which I think are putting people on the wrong track.

Velocity vs. rate

This can’t possibly be true! Nothing can move faster than the speed of light.

The camera does not record at the speed of light (slightly less than 300 000 000 meters per second, or 1 billion km/h). This confuses two common meanings of the word speed: ‘velocity’ and ‘rate’. It makes no sense to say that a camera records film frames at a particular velocity, much less the velocity of light; velocity means something is moving, and in this case nothing is moving fast at all. (Except for the light pulse itself, which of course travels at the velocity of light.)

Instead, by ‘recording speed’, it really means the camera is recording at the rate of 1 billion images per second (which is not the same thing as meters per second). There is a fundamental rule saying that no object can travel at a faster velocity than 300 million meters per second, but there is no such rule for rates.

(Although, if it were an old-fashioned film camera, the film would have to feed through the camera at a velocity faster than the speed of light, which would be impossible. So it’s lucky we live in the digital age.)

“We can see photons”

The other confusing thing is that the researcher says in the video that they can see photons moving through space — that’s strictly true, but not very helpful, since you are seeing photons moving through space right now too. That leads people to ask:

Hey, I thought you could only see light when it reflected off something into your eye! How can we see the photon moving through the bottle when it hasn’t hit anything yet?

Well, the thing we see moving through the bottle is a laser pulse – not one photon but a clump of trillions of them. Out of those trillions, some hit air molecules and fly off in all directions, and some of those happen to hit the camera. We say “the pulse scatters off the air.” So, it’s true, you can’t see photons directly unless they are flying right at you. What we’re actually watching is the air molecules lighting up as the laser pulse passes by.

None of this takes away from the fact that the front edge of that laser pulse travels with the speed of light — and we are watching that in slow motion! How cool is that?

Wisteria Hysteria

Dutch wireless disease?

Faced with the prospect of funding cuts from the new anti-intellectual government (“We don’t pay you to think, Mister Scientist!”), apparently someone at Wageningen University’s PR office has decided their results need to make more waves.

The university’s press release on their website is unfortunately only in Dutch, but in it they say that while observing young ash trees growing for three months, close proximity to six wireless routers seemed to cause discoloration and death of leaves. They then go on to say [translation mine],

Although the effects were observed using various sources of radiation and various trees, the researchers think it desirable to repeat the experiment, preferably during a longer period and on a larger scale.

This is code for “Our results were not statistically significant,” which in layman’s terms means “It might or might not be true, but we proved jack.” Now this research has the potential for far-reaching consequences in our modern society that depends on wireless internet and other sorts of electromagnetic waves, and the subject is also a touchy one, about which many people have a strong opinion which is totally unsupported by facts.

Let me state here once and for all that I don’t know the facts either. I tend to start out skeptical of these “studies” because of all the nonsense floating around, but like any good skeptic, I am open to being convinced by sound science. Several serious mistakes indicate, however, that while the as yet unpublished research may be sound, the press release doesn’t even come close:

• Mistake #1. Sending out a press release before the experiment was finished, apparently. What if this premature conclusion is disproved when the experiment is repeated over longer periods and with more trees, as the researchers say they need to do?
• Mistake #2. Misrepresenting collaborating parties in the press release. Only the city of Alphen is mentioned in this version of the press release, at whose request (and presumably, on whose dime) the research was carried out. However, other news items also list Delft University and the independent research lab TNO as parties in the research. That indicates to me that they must have been mentioned in an earlier version of the press release. Turns out, TNO issued a statement on their website explicitly distancing themselves from the conclusions! Let me assure you, this does not happen lightly in science.
• Mistake #3. Including numbers in the press release to inflate its importance, without explaining what they mean so that readers can understand.

Let me elaborate a little on Mistake #3, since numbers are important in this game. The exact words are [again, translation mine]:

…frequencies varying from 2412 to 2472 MHz, and a power of 100 mW EIRP at 50 cm distance.

So this just means that they used wireless routers, transmitting at 2.4 GHz, and placed them half a meter away from the trees. The frequency “variation” here means nothing. The researchers didn’t vary anything, those frequencies are just the standard channels used by 802.11b and 802.11g wireless. Why didn’t they test 5 GHz, which is also a common frequency used by wireless routers? Couldn’t they afford more than six routers?

I also had to look up the abbreviation EIRP, which stands for equivalent isotropically radiated power. This is too technical for me to get into in this post (although if you’re curious I’d be happy to explain it) which means it had no business being in a press release for the public. Also, it makes no sense to quote the EIRP in this case, so I’m guessing the PR office just got it off the side of the box the router came in. For nerds who know what I’m talking about, the power the tree is actually exposed to, depends not only on the distance to the source (and it falls off as 1/r²) but also on the surface the tree presents to the source!

The figure of 100 mW, besides being dubious, also means nothing to the average reader when taken out of context. Let me illustrate: a 100 mW green laser beam will blind you if you look into it. It might sting you if you stick your hand into it, and it might burn paper, all depending on how tightly it’s focused. But a regular 40-watt lightbulb, which radiates both light and heat, lights up your room nicely and harmlessly, despite radiating four hundred times as much power as the laser beam.

You stay the hell away from my baby, you internet tree-murderer!

All this has led to a spate of news articles with titles like “Wireless internet makes plants sick!” The irresponsibility exhibited here just astounds me. Hippies everywhere are going to don their tinfoil hats, and mobile phone users are going to be subjected to the kind of crusade that smokers have already had to face: “Put away that phone, you irresponsible jerk!” concerned mothers will scream at us. “Your secondhand radiation is giving my kid cancer!” Of course I’m exaggerating, but the damage is already done.

The worst example of this is Spits’ (a freely distributed newspaper, i.e. you get what you pay for) take on the article: you might as well stop reading when you see the giant radioactivity signs in the photo! Conflating ionizing nuclear radiation with non-ionizing electromagnetic radiation is pure fear-mongering, because they are as similar as Santa Claus and Parmesan cheese. If you do read beyond the photograph, bravely risking the loss of several IQ points, you see that Spits can’t even avoid contradicting themselves within the three-paragraph extent of the article! [translation mine.]

Whether radiation is really the cause of these phenomena, did not become clear in the study. […] In the study, the possibility that ultrafine particulates caused the phenomena was not ruled out. In any case, it is certain that the dead leaves and stunted growth were caused by radiation, according to the researchers.

The last sentence is also an outright lie, if I’m to believe the university’s press release. All because some PR monkey or fame-crazy researcher couldn’t wait for conclusive, publishable results and decided to fan the flames of the public’s fear instead. Sorry people, but when the results are not conclusive, that means the results are not conclusive. That’s the way science works. Suck it up and deal with it.

Hurdles Even Here

My good buddy Diederik was on the popular evening variety show De Wereld Draait Door Tuesday evening, being interviewed by the host Matthijs van Nieuwkerk about the Nobel prize going to the graphene people. It was a rousing success: on twitter, people were wondering whether he had a fan club, and clamoring for him to appear on the program more often! It was wonderful to see Diederik combine his gift for entertaining people with the contagious enthusiasm with which he does everything. The clip below is ten minutes well spent, if you speak Dutch that is.

He did a brilliant job, but if I’m to keep true to the principles of this blog, I’ll have to make a serious observation, not just congratulate him on a job well done — sorry, Diederik. Well, my observation is about the part that starts almost exactly two minutes into the interview. I’ve transcribed it and translated it into English below:

MVN: He won, and you were ecstatic, is that what you said?

DJ: Maybe not ecstatic, but I worked a lot with the material [graphene] at university, and it’s such a cool material! His winning is completely justified. It’s as if… well… if you read the papers from those days, then the American phrase “It’ll even walk your dog!” comes to mind. It’s strong, it’s flexible, you can see through it, it conducts infinitely better than copper — well, not infinitely of course — a million times better…

MVN: [interrupting] Please consider, Diederik, that not all the viewers have your brains!

Of course it’s good practice for talk show hosts to interrupt their guests when they’re not getting to the point quickly enough. I happen to think Matthijs van Nieuwkerk is a good interviewer. However, probably without even meaning to, he came uncomfortably close to the knee-jerk reaction that physicists are so familiar with: physicist starts talking, and interlocutor stops listening because he’s busy thinking “Oh no! He’s opening his mouth and I’m not going to understand anything that comes out!”

My geek heart breaks a little whenever that happens.

Not too much though, because Diederik went on to give one of the best popular-science explanations I’ve ever heard. Seriously, watch the video.

Fox News don’t know Jack Bleep

This travesty was brought to my attention: Freaky Physics Proves Parallel Universes Exist, a worse-than-amateurish piece of what I hesitate to call scientific journalism by Fox News. I won’t waste space on why I consider the article so terrible, since someone else has already heaped scorn upon it better than I could: The Worst Physics Article Ever. Besides, it’s Fox News, and by now it shouldn’t be a surprise that they just write down whatever the hell they feel like.

I want to draw your attention to something mentioned in the article that I find much more worrying and insidious: the name Fred Alan Wolf. Wolf is a former physicist, turned crackpot, and anytime you hear his name mentioned in connection with legitimate science, alarms should start going off inside your head.

I recognized him as one of the “experts” featured in What The Bleep Do We Know, a piece of pseudoscientific rubbish that basically asserts that quantum mechanics allows us to control our destiny by wishful thinking. Just to give you some background, it’s a propaganda film made and paid for by students of Ramtha’s School of Enlightenment. This hotbed of charlatans is led by one J. Z. Knight, a cigar-voiced medium from Washington who claims to channel a 35000-year-old warrior named Ramtha from the lost continent of Lemuria.

To be fair, not everyone interviewed in the movie is a fraud. For example, there’s Professor David Albert, who, according to this Salon.com article, spent hours on camera explaining why the film’s physics was utter nonsense, only to see his contribution spliced and edited so as to imply the exact opposite.

Fred Alan Wolf, on the other hand, was not misrepresented in the least. Wolf, whose stage name is Dr. Quantum, has been on the lecture circuit since the 1980’s promoting quantum wishful thinking, according to an interview on the What The Bleep website. This claptrap has been popularized more recently by Rhonda Byrne and cronies in the bestseller The Secret, and what do you know, Wolf also appeared in the film version of that.

As far as I’m concerned, Dr. Quantum has about as much to do with real, falsifiable science as the iPad has to do with blue cheese. One might ask why I care so much. Let me put it this way: if Fox News not giving a crap about proper science reporting is a slap in the face of my profession, then the thought of Fred Alan Wolf being any journalist’s go-to guy for quantum physics is a kick in the nads.

PS. If you’re interested in what was actually achieved in the experiment, hysterical claims of time travel aside, here is the original press release from UCSB. Or see Nature 464, pp. 697–703 (2010).