Student Questions: Light Therapy, the Bermuda Triangle, and Isaac Newton
I'm taking student questions again today, so everyone please take your seats and let's get started. Today's topics cover light therapy, the Bermuda Triangle, jumping to throw the Earth off its axis, vaccinations and autism, and environmental estrogens. Someone asked me why I only take student questions, and not questions from just anyone. The reason is that by reaching out to students, I imply an educational mission, thus endowing Skeptoid with "apparent" authority via the argumentum ad verecundiam logical fallacy. And I'll take any that I can get. Shall we proceed?
Seasonal Affective Disorder
Seasonal Affective Disorder is basically a depression that some people get during dark winter months, but there's more to it than that. In many cases, it's not a purely psychological condition. Some evidence suggests one cause could be an imbalance in melatonin, which is produced by the pineal gland during darkness; an actual biochemical response to the strange schedule of daylight and darkness.
Light therapy, which exposes the patient to bright short-wavelength blue light at a carefully timed interval each day, usually in the morning, has proven to be an effective treatment for most sufferers. Whether it's just a mild clinical depression caused by all the darkness or an actual hormone imbalance caused by the interruption of circadian rhythm, light therapy does make rational sense as a treatment. However, most patients report that it's inconvenient and few stick with it on their own. Other treatments include melatonin supplementation, antidepressants, and cognitive therapy.
Light therapy is also employed by alternative practitioners for a whole range of conditions for which it has no plausible clinical value. No matter what illness or New Age energy imbalance some naturopath tells you you have, somebody offers light therapy as a quack cure for it. Don't confuse light therapy's actual benefits with its fraudulent pseudoscientific misuse.
As you might suspect, seasonal affective disorder incidence is strongly correlated with latitude, but with one interesting exception. For reasons not well understood, people in Iceland or with Icelandic heritage seem virtually immune to the condition. A cheerful group in the wintertime, those Icelanders.
The Bermuda Triangle
The same causes that are behind disappearances anywhere else. Sometimes planes crash and ships sink, and although writers of scary books and producers of creepy TV shows like to adorn those in the Bermuda Triangle with mystery, the Coast Guard and the National Transportation Safety Board (NTSB) treat them the same as any other accidents. For every allegedly "mysterious" disappearance dramatized on television, there is generally an NTSB accident report detailing the actual cause determined (see official reports here for ships and aircraft). That's not to say some aren't explained; sometimes wrecks are never found and investigators are unable to determine a cause, as happens everywhere in the world. However the Coast Guard does say:
Whether accidents actually do happen in this area at a higher rate than in other places is known with certainty: They do not. Lloyd's of London, the largest insurer of shipping traffic, confirms this in its records, as does the US Navy. So to directly answer your question, what's really behind the Bermuda Triangle mystery is just a lot of pop fiction.
You've probably heard stories about mysterious fogs in the Bermuda Triangle, or compasses going crazy, or rogue waves, or mysterious upwellings from the deep. These are the types of tales that the sea has always produced, all over the world. Anyone who thinks the Bermuda Triangle has a monopoly on mysterious stories of the sea has not traveled or read very much. Like most stories, probably a lot of these have some basis in fact, but it is well established by a century of modern seafaring and oceanic surveying that no unexplained anomalies exist in the Bermuda Triangle.
Jumping to Disrupt the Earth's Rotation?
Although it would be fun if this were the case, Newton's first law makes it simply not so. Even if you gathered everyone together on one side of the planet, and they all jumped, they would indeed push the Earth away with a force equal to that which launched them into the air; but gravity would pull them and the Earth together again and they'd be right back where they started, in the same state of motion and with the same angular momentum. Only an external force, like an asteroid collision, could have the effect you describe.
Vaccines and Autism
It is true that some people believe that, which is tragic because there's a growing trend among misinformed parents to refuse to allow their children to be vaccinated, and new outbreaks of potentially fatal diseases like measles, whooping cough, diphtheria, hepatitis B, and polio have been the direct result. Among the worst offending communities is Ashland, Oregon, where 30% of kindergartners have been granted "personal belief" exemptions from the state, thus effectively eliminating "herd immunity" from the population. Only two US states require you to have a medical reason if you want to be exempted from the vaccination requirement to attend public school. A number of epidemics have broken out in communities with low vaccination rates, of diseases that had been otherwise largely eradicated by childhood vaccination.
The so-called "link" between autism and vaccines is a particularly bizarre superstition. It's an unfounded supposition depending on a chain of connections in which every single link is conclusively broken. Mythical link #1 is that autism can be caused by mercury. Autism is genetic, it has no environmental causes; at least none after the first trimester of gestation. Mythical link #2 is that mercury is found in the preservative thimerosal. In fact thimerosal contains ethylmercury, which is not absorbed by the body and is harmless; not methylmercury, which is the form responsible for mercury poisoning. Mythical link #3 is that thimerosal is found in vaccines. In fact thimerosal has not been an ingredient in childhood vaccines for over a decade.
Some parents also have been convinced that vaccination presents a dangerous immunological challenge, and so it's risky regardless of autism. This is a question that you should ask your pediatrician, not Jenny McCarthy. It's just not true. Even the common cold is a greater immunological challenge to the body than the full spectrum of early childhood vaccinations, and as you know, your child gets colds all the time and always manages to pull through. But you shouldn't get your children's medical advice from some random podcast any more than you should get it from deluded, uneducated celebrities. All you need to do is look at the data of disease rates among vaccinated and non-vaccinated children to answer any question about what you should do. There's no correlation between autism and vaccination rates, but there's huge correlation between vaccination and rates of diseases that the vaccines prevent.
Update. I did receive the following email from Dr. David Gorski at the Science Based Medicine blog, which is appropriate to include here:
Environmental estrogens, more properly called endocrine disruptors, are compounds that chemically bind to a living cell's hormone receptors, thus taking the place of the body's natural hormone that would normally bind there. This interferes with the body's normal hormone action. Endocrine disruptors are found throughout nature and the environment, but recent years have seen the Internet come alive with alarmist articles (like this and this and this) that they are all around us at dangerous levels, often in household chemicals or everyday products. These articles tend to mention all the "usual suspects": dioxin, DDT, BPA, PCBs, etc. and often blame these as a cause of breast cancer, ADHD, autism... again, all the usual suspects.
Virtually the only case you ever hear cited is one in Florida where alligators in Lake Apopka were found to have abnormal genitalia, linked to endocrine disruptors in the water. These reports often neglect to mention that the lake is an EPA Superfund site, meaning it's a known heavily contaminated toxic waste site. But if you don't live in and drink heavily contaminated toxic waste water, what kind of exposure to endocrine disruptors do you really have? Well, to put it in perspective, you get more from a single serving of sunflower seeds, soybeans or alfalfa sprouts than you do from a lifetime use of water bottles containing BPA.
Endocrine disruptors are in the environment. Most that humans and animals do now and always have consumed come from normal dietary and environmental exposure, such as the vegetables just mentioned. You would need to have a dose orders of magnitudes higher than that for it to have any adverse effect, and these consumer products mentioned in the headlines simply don't have that. Yes, endocrine disruptors are found in these products, but at dosages orders of magnitude below maximum safe levels. The same can be said of virtually any dangerous compound you like. There have yet to be any documented cases of humans being affected by endocrine disruptors in consumer products, so until there are, you can chalk it up to more sensationalist reporting on an otherwise slow news day.
If you're a student and would like to have your question answered on Skeptoid, please come to Skeptoid.com and click on Student Questions. I'm ready to tackle all the stories you've heard, from urban legends to consumer frauds to the paranormal to conspiracy theories. So keep them coming; the only stupid question is the one you didn't ask.
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