Friday, September 13, 2002

It's not that I don't <i>want</i> my kids to have superpowers...

A basic irrational fear of excess radiation has kept me from buying all sorts of cool devices, including mobile phones and wireless networking devices for my home. The fact that no adverse effects have been found in years of study doesn't help my fear much. It is an irrational fear, after all.

My friend Tom Duff says that, in that band that wireless devices operate, the wavelength is so large that the signal doesn't carry enough energy to cause chemical state changes in cells. Thus, it can't break chemical bonds or otherwise fiddle with any cellular state that matters. Thus, no danger to whatever body parts I might be paranoid about. (Phones spend their time in pants pockets, shirt pockets, and next to the head. All the vital organs! Yay!)

His logic makes sense to me, though I'm mostly taking his word for it. Just as I stopped glaring suspiciously at my microwave several years ago, I'm beginning to warm up to the idea of a mobile phone. Travelling last weekend reminded me how useful they are, and with a baby on the way, it would help for me to be more accessible in an emergency.

So today I was actually shopping around the web for mobile phones, checking out the various carriers, trying to make sense of the endless sea of calling plans. I'm this close to buying one, and I pause for a moment to read Slashdot, as I often do. Lo and behold, an article on wearable technology offhandedly mentions Levi's new anti-radiation pants for mobile phone users.

Rrrgh. Irrational fear returns. Dammit. I might as well just sprinkle goat's blood around all the electrical outlets in my apartment to keep the electricity demons out.

They're there, you know. In the walls. Watching.


  1. Just for reference, bond energies for organic compounds are in the 50 to 200 kcal/mole range. (These loonie units were divised for the convenience of 1930's era wet chemists, who measured quantities of chemicals with triple-beam balances and reacted them by heating with bunsen burners.) Unless I did the arithmetic wrong (there's a chance, but I checked it several times) those energies correspond to light with wavelengths between about 500 and 150 nanometers. Cell phones radiate in the 900 Mhz and 1800 Ghz bands, where the wavelengths are between 30 and 15 centimeters. The energy in those cell-phone photons is a factor of 3 hundred thousand or more too small to be diddling your body chemistry. But what if you get a million of those weakling cell-phone photons? Nothing happens, because chemical bonding is a quantum-mechanical phenomenon. If a single photon doesn't put enough energy in the bond to change its state, the bond won't absorb the photon at all.
    The only other applicable way that science knows of to break chemical bonds is by heating, and the radiation from a cell phone can certainly do that. If your cell phone starts running hotter than body temperature, you might have cause to worry. But I'd worry more about whether the phone was broken than about whether the heat is going to hurt you.

  2. Here's something you don't want to hear: while they've never proven anything other than short-term memory loss from keeping a cellphone next to your head, they *have* shown that cellphones next to a balloon full of amino acids will break down the amino acids over time. So it's not clear why this happens necessarily, or that it corresponds to any particular phenomenon taking place in your vital organs, but chemical bonds *are* affected by close proximity to an operating cellphone over time.

  3. I don't know what to say. My previous comment was intended to deal with the study that Noah brought up. Let me put it more plainly. If this study (which it would be really nice to have a reference to) is true, then not only are cell phones dangerous, but the laws of physics and chemistry are incorrect at a fundamental level. The former is of no particular consequence, except for the cell phone industry. The latter contradicts the life's work of every chemist (and many physicists) of the last 90 years. So, what conclusion should we draw? Certainly not that the whole edifice of chemical physics needs to be demolished, as taking this experiment at face value would require.

  4. Perhaps it's a result of my inadequate knowledge of quantum processes in chemistry (which I readily admit), but I'd thought that an atom or molecule could be hit with radiation (photons, usually) which would kick electrons up one or more orbitals. Usually they come right back down, generating new photons (the origin of the phrase "quantum leap"), but I thought they didn't necessarily have to and could remain with electrons in higher orbitals for some nonzero time afterward. If so then multiple photons of different wavelengths could hit over that nonzero time, allowing many of them to collectively cause the breaking of the chemical bonds in question.

  5. What Noah says is true; not all state changes break bonds. Nevertheless, a photon that is not energetic enough to change quantum states will not be absorbed, and the smallest change from the ground state requires a substantial fraction of the total bond energy. (I'm sorry, I glossed over this -- I can't find the exact numbers.) But cell phone photons are smaller than the bond energies by a factor of 300,000. If they were a problem, a sunny day would turn you into a cloud of monatomic gas.

  6. Yeah, that's why I don't go outside more often :-)

  7. Here's a creepy coincidence: the article number for this item is 137, which is (to 4 figures of accuracy) the fine structure constant (well, it's reciprocal, which is how most physicists remember it), the most mysterious number in quantum mechanics.