Cell phones and Cancer?
I may edit this post as critiques are offered and discussed.
Part 1
First, some basics.
-Cellphones work by transmitting information via radio waves.
-Radio waves are part of the Electromagnetic Spectrum, which I suggest you take a look at here.
-All forms of radiation in the EM spectrum are made of packets called "photons." That's not just the light you can see, that's microwaves and X-rays and the radio/TV waves that make up our over-the-air broadcasts. All photons. The only difference between X-rays and radio waves is that the X-ray photons "vibrate" at a higher frequency. That's the only difference.
-This difference in "vibration" makes X-rays more energetic than radio waves. Any X-ray photon is automatically more energetic (has more energy) than any radio wave, or red light photon, or microwave.
The method by which some parts of the EM Spectrum cause cancer is by having photons so energetic that they break the molecular bonds of your DNA molecules. Ultraviolet, the radiation that's just beyond what we can see towards the purple end of the spectrum, can damage your DNA molecules. So can X-rays and Gamma rays.
Here's the kicker: the only thing that matters in breaking molecular bonds is the energy of the individual photon, not how many photons there are. Red light, no matter how abundant around you, will never damage your DNA like that. UV light, now matter how scarce, is always capable of damaging your DNA. (Fortunately, UV light never makes it past the upper layers of your skin, which is why you need sunblock and not a lead vest to go out when it's sunny. This is also why X-rays, which go through most of your tissue like light through a sheet of paper, can be dangerous to your internal organs in addition to your skin.)
The only reason that greater UV levels lead to greater risk of skin cancer is that they have more chances to hit your DNA and damage it if there are more photons shooting around, giving you more DNA damage than your body can easily repair or shrug off. Enough mutations all happening at once and you're more likely to develop a cancer.
Now remember, only the energy of the individual photon matters when it comes to breaking molecular bonds here. Why does that make cell phones safe and cancer-less? Because only UV rays and above can damage your DNA by breaking its bonds. Let me say that again: Only photons that have at least the frequency of UV light can damage your DNA molecules. Therefore, UV rays and above are classified as "ionizing radiation." Anything less energetic on the spectrum (from visible light all the way down to microwaves and radio waves, is called "non-ionizing radiation." It's not energetic enough to ionize your lovely DNA molecules (break the bonds holding them together).
Part 2
Slightly more advanced science: The energy of any photon is dependent on multiplying its frequency by the Planck Constant (h). As you may be able to tell, the Planck Constant doesn't change. This means that frequency differences alone determine how energetic photons are.
You can express like so: E = v*h.
E is "energy," v is "frequency," and h is the Planck Constant (which, again, doesn't change). Does this make sense of the statements above about only frequency determining the energy of photons now? Frequency is the only thing that can change on the right side of = to make the energy on the other side different.
The reason I showed you this equation is because I'm going to make an analogy. Imagine we model photons zapping DNA molecules by throwing things at a brick wall. The energy of the photon would here be represented by the (linear) momentum of whatever we're throwing at the wall. This is usually expressed as p = m*velocity, velocity being how fast the object's moving and m being how massive it is.
Because these two equations are set up the same way, my analogy will be that the molecular bonds in DNA are the brick wall. We are throwing objects of different masses at the wall, all with the same speed, just like photons with different frequencies but the same h are zapping the DNA.
DNA and radiation: E = v*h
Wall and missiles: p = m*velocity
For the sake of convenience, we'll set the velocity of all our objects as 88 miles per hour, heading towards the wall.
Now, imagine you have a low-energy photon, with a low frequency (say, microwave: see the big Spectrum chart) zapping the DNA. This is like throwing a low-mass object at the brick wall (say, a ping-pong ball) at 88 mph.
Just as the ping-pong ball is not massive enough to knock a hole in the brick wall when you throw it at @88mph, neither is a microwave photon going to break the bonds of your DNA molecule.
Ionizing radiation is much more energetic than microwaves because of its higher frequency. X-rays are so energetic that they can break the bonds of DNA molecules. In our analogy, this would be like taking a high mass object (say, a DeLorean) at the same 88mph speed as the ping-pong ball and running it into the brick wall. A DeLorean's mass is much greater than the ball's, so if they're moving at the same speed the car will have much greater momentum when it collides with the wall. You can, in fact, break a brick wall by running into it at 88mph with a DeLorean.
But what about the amount or intensity of radio waves? They don't matter. Just like you cannot break down a brick wall by throwing a series of 1 million ping-pong balls at it, you cannot break DNA's molecular bonds by zapping it with a high amount of radio waves. If radio waves cannot break your DNA molecules, they cannot give you cancer.
Part 3
Wait, you say. Don't microwaves cook things? Yep, but not by breaking molecular bonds. Instead, microwave ovens work by using specific frequencies of microwave radiation to cause water (and fat) molecules to rotate very rapidly, producing lots of friction and therefore heat. But heat doesn't cause cancer. At enough high levels, heat can cause chemical changes, re-shaping the proteins that hold meat (aka flesh) together, but that's called "cooking." If you are cooking, the last thing you have to worry about is growing a tumor.
The amount of heat that can be induced in a microwaveable burrito is limited by the amount of power the microwave can put out, usually expressed in Watts (and found on a sticker somewhere advertising how powerful the unit is supposed to be). Radio waves from cell phones can also be measured in Watts. Do cell phones produce enough energy as heat to cook your brain?
The average microwave oven is usually rated somewhere between 700 and 1500 Watts. The radios in cell phones put out much less, usually expressed in milliWatts, or thousandths of a single Watt. The average cell phone is probably rated at 250 milliWatts, or about a quarter of a whole Watt. The low-wattage, 700W microwave oven is therefore using 2,800 times more power than the cell phone. Assuming 100% efficiency (which never happens) for both, you would have to focus all the radio energy of 2,800 cell phones on the same spot to get comparable heating.
In reality, it's even worse: cellphones do not operate in the same frequency as microwave ovens. You wouldn't want them to, since you want cell phone radio waves to travel as far as possible. If their energy were absorbed by water like the waves of a microwave oven, the moisture in the air would prevent them from traveling very far before their energy started to dip too low to be useful. So manufacturers choose frequencies of radio waves that pass right through water molecules without being absorbed very much: microwave ovens are built on the opposite principle. It's unlikely that you could "nuke" a burrito even with 2,800 cell phones concentrating their radiation on it.
So for the two reasons above (extremely low power and frequencies that skip right over the molecules of your body), you cannot "microwave" your brain with cellphones. Your brain is not in danger of being cooked even if you have a cellphone surgically implanted in your ear, unless your lithium-ion battery catches fire.
Part 4
All of this applies to things other than cell phones. Years ago, there was a scare that the EMF fields generated by high-voltage power lines might cause cancer. These fears never had a solid basis in science and we now know, through decades with many large and careful studies, that they are completely untrue. Power lines do not give off ionizing radiation, just as cellphones don't. You need ultraviolet and higher rays to get the potential for cancer to form. Not just powerlines, any kind of "EMF" generated by common electrical wiring or equipment is too low-frequency to be ionizing radiation. If you hear someone talk about "living too close to the power lines" or something like that and worrying about cancer or health problems, you can now assure them that their fears are baseless.
What does this mean for people who claim to be "allergic" to EMF and Wi-Fi waves? It means they're probably fooling themselves. They have somehow convinced themselves that there is a link between feeling some kind of unease or symptom and being near a wireless router or a cell phone. But we are all constantly bathed in this radiation all day and night: television, radio, cell phone signals are everywhere. If we could see them like we do with visible light, our cities would glow with it all. Since they're surrounded by these waves constantly but only display symptoms some of the time, it's much more likely that there is something else at work and they have made a faulty connection between feeling bad and hearing a phone go off or installing a new router. Probably, it's in their heads rather than in the waves.
There's a lot of text behind the cut, so there's the TL;DR version: Electromagnetic Spectrum
Only the UV rays and higher up can potentially cause cancer. Radio, EMF, microwaves, visible light, none of them will ever give you cancer no matter how abundant or intense they are.
This infodump was inspired by seeing crap on the internet about cell phones and tumors, or powerlines and leukemia. What got me fired up about it was actually one of the science books I'm currently reading. Yes, that's right, I'm reading MORE science books! I even borrowed yet another Carl Sagan book from the library! I CAN STOP ANY TIME. *cough* Anyway, right now I'm reading Voodoo Science by Robert Park, about the many ways people (even scientists) can get science wrong, and keep pushing for things that aren't there: cold fusion, infinite energy, magnet therapy, homeopathy, and a host of other things that have gone in and out of popularity over the years. I consider it an invaluable book at the very least because of the insight it provides on how things are run (courts, senate committee hearings, etc.) and how they can either root out or promote bad science.
The weather finally turned nice yesterday. Sunny, breezy, nary a cloud in the sky. There was a slight Autumn chill in the air, but only just enough to be noticeable. Today it's warmer, but also windier.