OK, back to business. A physics professor from a college in the East replies to this item, in which a software engineer explained why new "enhanced" backscatter-radiation TSA machines can't be assumed to be safe. The physics professor writes:

>>There is no such thing as a risk-free dose of ionizing radiation. The federal government studied this using beagles right after World War II and found no safe dosage level. And for good reason.



The reason Albert Einstein won the Nobel Prize was for explaining the photoelectric effect, not for relativity. His explanation involved the discovery that light is absorbed and emitted in discrete energy packets called photons, like a stream of particle. Photons are only absorbed or emitted one at a time, and their energy depends on their frequency.



We learn two things relevant to current news from this:

1. All microwave photons are far too weak to cause damage to molecules through their absorption. The energy level of a microwave photon is sufficient to cause a molecule to rotate or vibrate (this is how microwave ovens work) but not to cause it to disintegrate or modify its structure, and those are essential requirements for causing a DNA molecule to mutate into a malignant strand. Epidemiology cannot answer this question because its methods are not aware of physical laws. They can place a statistical limit on mutagenicity, but physics actually rules it out as physically impossible. Lesson? Cell phones do not cause cancer. Period.



2. On the other hand, X-rays cause molecular damage very easily because they are extremely energetic. In fact, this is the reason why they permit you to see inside things. Anything further up the spectrum than the near-UV is capable of causing cancer. But UV is not energetic enough to penetrate. It is absorbed in the outer layers of the skin, and so can cause skin cancer but not, say, lung cancer. X-rays penetrate. They cause cancer everywhere. And dosage is cumulative over your entire lifetime. Every time you have an X-ray, you slightly increase your chances of contracting cancer. This is why the radiologist always goes into another (shielded) room and puts a lead blanket over parts of you that they aren't interested in. Now each additional dose is a small risk increase, to be sure, and the benefits of medical treatment are generally worth the risk (though I am frequently irritated by the tendency of dentists to X-ray my head with wild abandon).



So I will not go into the naked scanner under any circumstances. It is only for PR purposes, and I don't give a shit about helping Obama or Pistole or anyone else primp their public image. Millimeter wave is safe, X-ray is not, but you never know which one you're getting. TSA workers should be up in arms since they're standing around the machines unshielded all day long. This will eventually come back to bite the government.



You can take that from a physicist.



Oh, and by the way, being afraid of irradiated breast milk is idiotic. That radiation is not entering your body and so can't damage it. On the other hand, so long as the TSA has a policy [of treating breast milk as a "medical fluid'] , they need to honor it.<<

And, from another reader, a report on his first enhanced pat-down:

>>Very exciting; I was selected and opted out. It was pretty thorough; the guy kept telling me "I've reached a sensitive area, I will now use the back of my hand." Lo and behold they found nothing. Although they were very interested in my belt loops and pant cuffs. The guy was talkative and noticing a scar on my elbow (which I got hiking with enough pack weight I barely noticed it, but it is quite prevalent now) tried to talk about that--it was clear he didn't want to be doing this but had found a way to cope. Rather professional--I was somewhat impressed. I think that, in the future, I'll forgo the radiation again.<<

That's my plan too, when the time comes.