Privacy for Privacy's Sake

With all the Facebook and Google+ discussion flying around the Internet, one word keeps popping up over and over again: "privacy".

One phrase in particular keeps slamming my ear-drums: "I know privacy is important, but..."

So here's my question: why is privacy important?

Of course if you're a criminal or something, and you genuinely do have something to hide, privacy would be important to you. But for the rest of us who don't do anything of particular interest to anyone (even our own loved ones), why does privacy matter?

In a world where Twitter and Facebook are flooded with people broadcasting to the world what they had for breakfast, and nobody gives a crap, is privacy relevant at all?

I should point out that in general I'm a pretty private person. I feel a natural inclination towards keeping things private.

But why? What's the benefit to keeping things private? Assuming there is a rational reason for privacy, where does one draw the line between what should be kept private and what shouldn't?

Episode #17: Killer asteroids, killer apes and Dr. Adrian Tiplady | Consilience

Episode #17: Killer asteroids, killer apes and Dr. Adrian Tiplady | Consilience

The universe is trying to kill you! (and bushbabies!) Find out how!

Consilience #16: Relativity, Oprah and Rebecca Watson | Consilience

Episode #16: Relativity, Oprah and Rebecca Watson | Consilience

It's out! Go listen! Quickly! It's Rebecca Watson! YES!!! REBECCA WATSON!!!

Consilience Episode #6: Justice & snacking, fine wines, and the Big Bang

Episode #6 of Consilience is out!

Go! Quickly! Before we run out of electrons to send it on!

Consilience Episode 2

Angry Monkey says "GO NAO!"

Is out!

This week we talk about space, dinosaurs, monkeys, birds who pilot missiles and chat to Steven Novella some more.

Go to the Consilience blog now! Hurry!

Consilience: An African Science Podcast

I'm very pleased top announce that as of today, I am an official contributor to a real podcast from Africa, by Africans, about science!

That's right, ladies and gentlemen! This afternoon we officially launched with the very first episode of Consilience: An African Science Podcast. 

My esteemed co-contributors (co-conspirators?) are, as you might expect, Michael Meadon, of Ionian Enchantment, and Angela Meadon, The Skeptic Detective.

Unfortunately due to Apple's regulations you won't see us in the iTunes podcast directory yet (it takes a few weeks), but feel free to subscribe to our RSS feed for your weekly dose of African scienciness!

(Better yet, use Google Reader and Google Listen. Just sayin')

TMI About BMI

I don't know what this means.

If you've ever been anywhere near a gym, personal trainer or fitness magazine, you have, no doubt been exposed to the notion of Body Mass Index (BMI). It's a simple calculation that produces a number that allegedly defines how fat (and therefore healthy) you are. Awesome, right?

What Is It?

In essence it's a proxy, a rough way of estimating how much of your body-mass is made up of fat tissue. It works like this:

Your mass in Kilograms divided by your height in Meters squared:

Ideally, the result should be between 20 and 25. Otherwise you would fall somewhere on this scale:

It's that easy!

Smell too easy to you? Yeah, me too.

What's Wrong With It?

Well the most obvious shortcoming is that it tries to quantify something (body fat percentage) without actually measuring that thing. This would be understandable if it was prohibitively difficult to measure body fat. If that were the case, it would make sense to use some other trick as a proxy - an alternate measurement that can provide reliable information about the thing you're interested in.

So we have two claims now:

1. Body fat is too difficult to measure directly.
2. BMI is a reliable proxy for body fat.

Let's take them one at a time.

Measuring Body Fat

As with most things, the whole idea of fat is more complicated than we might think. Firstly, there's more than just one kind of fat. Actually there are three kinds. When it comes to the kind of fat which, when found in excess, is strongly correlated with all sorts of health risks, the one we're talking about is Abdominal or Visceral Fat. That's also the one that piles up on your belly (or hips & thighs if you happen to be of the female persuasion). So that's also the one that will most likely be of interest to people going to the gym.

Visceral Fat

When it comes to measuring the fat content of your body, there are actually quite a few different ways of doing it, ranging from the impractical to the useless. And some others.

On the impractical side of things, we have the Dual-energy X-ray absorptiometry technique. This method involves a full body scan using two different X-rays in order to construct an image of your body's composition. Although this is an excellent tool for finding out exactly how much fat you've got, it's cumbersome and expensive. It's not exactly something you can do at home, or even at the gym. A qualified radiologist has to do it, not a personal trainer. And access to this sort of technology is better reserved for people who need it for medical purposes - like measuring bone density in patients suffering from Osteoperosis. Chubby-checking is probably low on their list of priorities, unless you're in obvious danger.

Skin-fold technique.

On the useless end is the skin-fold technique. As the name suggests, a section of skin is pinched with a pair of calipers, and its thickness is measured. While this is a perfectly good way of measuring the quantity of Subcutaneous Fat in your hypodermis, that's not the fat we're looking for. Visceral Fat doesn't live there.

But there is a ray of hope, and it comes in the form of a infra-red light! A beam of old-fashioned IR light can penetrate the skin and muscle tissue of your upper arm and, in doing so, reveals the quantity of Visceral Fat stored inside the muscle! Now, as we said, people tend not to store much fat in their biceps, but it's a pretty reliable extrapolation from the quantity of fat in your bicep (as compared to a statistical average) to the quantity in your abdominal region.

Fat Scanner Booth

The clear advantage of the IR beam technique is that it's reliable, inexpensive and easy. it can be done with a hand-held device, by a chimpanzee wearing spandex (or a personal trainer). Although it's not the sort of device you'd be likely to buy for home use, odds are your gym has at least one lying around. (If you live in South Africa and go to Virgin Active gyms like I do, that little Discovery Health booth that measures you in all sorts of ways, and records the results on your account, has one of these devices built in.)

Right, so, measuring body fat isn't really all that hard. Although getting a precise reading is difficult, it's easy enough to get a good, reliable result.


Reliability of BMI

Here's the thing: BMI was originally developed as a statistical heuristic for comparing relative body fat levels in populations against each other. And it seems to be pretty good at that. But it wasn't really ever intended for use by individuals as a diagnostic tool.

Firstly, it's based on some pretty heavy-handed assumptions about distribution of body fat in relation to height and mass. While it may describe the average person fairly well, outliers (like athletes, for example) will be poorly represented: weight-lifters generally register as "Obese" on the BMI scale (30 and over), while marathon-runners register as "Underweight" (BMI 16 - 18.5).

In addition, the BMI classification difference between Overweight and Normal doesn't seem to be supported by epidemiological data. There's no difference in life expectancy between those two groups.

The list goes on. BMI has its uses, but it's not really meant to help you track your own, personal health. It sucks at that.

So Then?

Essentially, if you're interested in tracking your body fat percentage as a metric contributing to your own health, it's probably best to steer clear of using BMI. Rather go with direct body fat measurements instead.

Better yet, talk to your doctor about what steps you can take to manage your health. Ask how much exercise you should be be doing, and whether or not you should see a Dietitian (NOT a Nutritionist!) about managing your diet. No website or magazine can give you a reliable estimate of how healthy you are.

And please remember that personal trainers, however muscly they may be, are not medically trained. If they were, they would be working in medical practice, not in your gym. That usually doesn't stop them from offering all kinds of advice on nutrition, supplementation and even medical interventions. You should take their advice on how many reps to do on the leg-press machine, but take everything else with a grain of salt. And when in doubt, check with your doctor.

Exercise Your Right to Vote!

So you Joburg sceptics are probably all aware by now that we're coming up to another Sceptics in the Pub next week. What we haven't yet decided is where we'll be doing it.

For those who have been coming for a while, you'll have noticed that we've made a habit of jumping around every month to give people from different parts of this enormous city a chance to make it who might otherwise not have been able to. Last month we had it at Cresta Shopping Centre in North-western Joburg, so we're looking to change it up again. Probably somewhere East of centre.

So where should we do it? Have your say! Tell us where you'd like to be sceptical in a pub by submitting your suggestions and voting on others over at our Google Moderator board.

And don't stop at just once... more suggestions are being thrown up there all the time. Keep coming back and voting so we know the will of the people!

(We won't necessarily use the top-rated suggestion every time though. Like I said, we like to keep it varied. But we'll try to pick from the top five at least.)

Yay! Democracy!

Cell-phones and the Brain

I know it's popular to pick on established institutions and point out how much they suck lately. I'm going to resist the urge to do that, and simply point out on example of how a generally good institution, Scientific American, seems to have lost the plot.

(before I start it's disclaimer time: although I no longer work for a cellular operator, I'm a fan of cellular technology in general. So while I may have some emotional bias in this area, I try very hard to be rational about it - it's not like my livelihood depends on it or anything.)

Unless you've been living under a rock for the last ten years, you've no doubt come across the claim that cell-phones are somehow bad for your health. The most popular claim is that it somehow causes brain cancer.

While there's still scope for long-term epidemiological studies to provide further insight, the best data we have so far suggests that there is no such effect. And if there is an effect, it's probably so small as to be virtually indistinguishable from chance.

Not only that, but the whole idea that cell-phones could do any kind of damage like that is highly implausible. They just don't work that way.

For a more comprehensive look at the issue, head over to Steve Novella's Neurologica Blog. He knows way more about this than I do.

However data never got in the way of a good health scare, and misinformed people have been making a fuss over the health risks of cell-phone radiation as long as there have been cell-phones. And it's not a small fuss either - people have been losing their goddam minds over this. It's becoming a real problem!

Given that the whole cell-phone health concerns thing is such a hot-button topic right now, why the hell would a publication that has a reputation for being a bastion for reason and rationality such as Scientific American publish a steaming pile of bullshit like this: "Cell phone emissions change brain metabolism - By Katherine Harmon"?

What's the Story?

In summary, this reports on a study being published in the Journal of the American Medical Association (how they got into that publication is a mystery to me). The study is an experimental one in which they expose healthy human subjects to cellphone radiation for a bit, then run them through a PET scanner to see what effect it had on the brain's glucose metabolism. And guess what? They found an effect.

Wow! That's hectic, right?

No. It's bullshit, and here's why. Without going into any deep analysis on their results, I see two huge problems with this study.

Problem the First

This was an experimental study in which they recruited volunteers to participate. Not 100 000 volunteers. Not  10 000. Not even 1000. Those would be pretty good studies. No, they recruited 47 volunteers. Forty seven.

I don't have to be a professional scientist to know that a sample of 47 is way too small to produce any meaningful results. All you need is one anomalous result and the whole graph is thrown out of kilter. That's not enough people!

Problem the Second

They found that the brain glucose metabolism in areas of the brain close to the active antenna were"significantly higher". What do they define as "significantly"? Seven percent. That's right, seven percent.

I don't have to be a professional statistician to know that 7% is not significant. It's around what you'd expect to see with random noise in the result. And considering they had such a small sample (forty seven!) that noise ratio would probably be even higher!

So What Am I Saying?

This study has produced practically nothing. At best this might be considered an interesting preliminary result, prompting further study. But I think even that would be generous. I don't think it's interesting at all - it looks like a negative result to me.

That said, I can't really fault the researchers here. Despite their willingness to speculate wildly on all sorts of ways cell-phones might be killing us, at least they're doing science (albeit bad science).

I don't even blame Katherine Harmon. While her piece was a little alarmist, she at least made an effort to include some sceptical opinion in there. While I think it leans a little too far towards the false balance side of things, at least there was balance of some sort.

No, the person I blame is the idiot Scientific American editor who put that sensationalist headline on the piece. It's clearly deliberately provocative. And thanks to that guy (or girl), the cell-phone radiation cranks will be all over this shit like teenage white girls on Justin Beiber. We won't hear the end of it!

Thanks for nothing, dumbass!

Holy Crap! 2012!

Apocalypse

Yes, I know, this topic has been done to death elsewhere, but I thought it might be fun for me to try my hand at it too. Hopefully it'll be fun for you also.

Okay, so what's the deal about 2012?

There's a popular belief that the world as we know it will end next year, in 2012. Some versions of the story suggest that it will happen specifically on the 21st of December. While doomsday prophecies are nothing new, this particular date, 21/12/2012, seems to be acting as a lightning-rod for a vast array of different foretellings of disaster.

I'll look at some of the more popular predictions in depth, but first let's try and figure out why this date in particular seems to have gotten into the minds of the eschatological amongst us.

The Mayans Predicted the End of the World

Right, so, centuries ago, ancient Mayans kept a calendar that is still regarded as being a very good one. It was all very complicated and clever, and even included a fancy decimal system for measuring smaller units of time within larger ones, and so on.

That calendar comes to an end in the 21st of December 2012. Obviously that means the world is ending on that day, right?

Long Count

Let's think about that for a minute. In Western society we use the Gregorian Calendar. It's also a pretty good one; it's complicated and clever and even includes a fancy decimal system for measuring smaller units of time within larger ones, and so on. About eleven years ago everyone in the world who uses the Gregorian Calendar had to stop writing the current year as "1999", and instead had to use a different digit to represent the thousands column of the date: "2000".

A thousand years before that, the Gregorian Calendar didn't exist yet, but it's predecessor the Julian Calendar did. One day, roughly 1011 years ago, everyone who used the Julian Calendar had to add an extra digit to the date in order to express the current year: they went from "999" to "1000". The hundreds, tens and units columns rolled over to zero, and a new column, the thousands, clicked over to 1.

That's what happens to the Mayan Calendar on 21/12/2012: the Long Count Calendar's largest column (called the B'ak'tun) ticks over to zero, initiating a new, previously unused column to click over to one. That's all. It's just a function of the decimal system in action, clocking over to a new column. No biggie.

But it's the Mayans' calendar, right? Maybe we should ask them whether they think the ticking over of the Long Count is a prediction of the end of the world.

(YouTube Link)

Right, so the Mayans didn't predict the end of the world. Not in 2012 or at any other time. Doomsday prophecies clearly weren't as important a part of their culture as it is a part of ours. Interpreting the "end" of their calendar as a prediction of the end of the world is foolish at best, and an outright lie at worst. So knock it off.

But Planet X!

One of the many apocalypses (is that the correct plural?) predicted by some to take place in 2012 is the appearance of the mysterious Planet X - a major planetary body somehow bound to our Sun that will pass through the inner solar system wreaking havoc upon the Earth, either by a direct collision or just gravitational or tidal perturbation.

This isn't a new idea, in fact 2012 is just the latest in a long line of dates put forward for this inevitable catastrophe. So what is Planet X?

Not a Planet

The term "Planet X" is one used by some astronomers to describe a planet in our solar system that was predicted to exist, but had not yet been observed (and therefore not yet named). In the past, both Neptune and Pluto were referred to as Planet X before they were observed and officially named. The Planet X referred to in these prophecies is neither Neptune nor Pluto, but rather another supposed planetary body that real scientists either haven't discovered yet, or are somehow keeping a secret from everybody.

Some sceptics might recognise this Planet X is the one often called "Nibiru" by the Ancient Astronaut Theory cranks (although as far as I know, the big names in Ancient Astronauts, Zecharia Sitchin and Michael Tellinger, aren't involved in the whole 2012 thing, a lot of their cohorts and fans most definitely are). The Nibiru notion goes that our sun has a companion object, either a large, massive planet or a brown dwarf star that's on a large, highly elliptical orbit. That orbit brings Nibiru into the inner solar system every so many centuries, and while it's here, it causes all manner of catastrophes.

That all sounds very interesting and terrifying. But what does the science say?

Nada. Not a thing. There's no evidence whatsoever of such an object existing. And if it did exist, and it was only a year away, not only would professional astronomers be able to see it by now, but amateur astronomers (such as myself) would be able to see it too. On any given night there are literally thousands of telescopes pointed at the sky, all of which would be capable of detecting such an object. Yet not a single person has reported seeing it. Not one. Are all those amateur astronomers also in on the conspiracy? Are they all just missing a giant fucking planet in the sky? Or did someone make this planet up?

Occam's Razor tells us which answer to go with. (Someone made it up.) Of course the cranks have plenty of photos of what they claim to be Nibiru, but to date, every single one of those has been shown to be either fake, or a misinterpreted image of something else entirely.

(It should be noted that there is an ongoing question as to whether the Sun does have a far-out, massive companion object, often referred to as Nemesis. But that object wouldn't ever come close enough to the Sun to cause any trouble to the other planets. If it exists, it's so far away that its existence is still in question... that should tell you something)

But There's an Alignment of Things and a Polar Shift!

No.

There's a cluster of different claims about the Earth coming into some sort of "alignment" with the other planets in the solar system, the centre of the galaxy or all sorts of other things which will either cause some sort of "polar shift" or bathe us all in deadly radiation or something. This is the one that was the basis for the movie "2012".

Variously, this story goes that in 2012, all or most of the planets in the solar system will line up, causing an unprecedented effect of combining all the gravitational fields in a row, which will exert a torque on the Earth, flipping it over on its side. Which would obviously be a bad thing.

Okay, so there are two ideas wrapped up in there. Let's pull them apart.

Idea 1: There will be a major planetary alignment in 2012. Nope. That one's just wrong. These sorts of alignments are pretty common, and they've happened a number of times during history, but there are none scheduled to occur in 2012... just the usual conjunctions that happen every year.

Idea 2: A planetary alignment of this kind could change the rotational axis of the Earth by exerting a torque on it. I'm not a physicist, so I stand to be corrected here, but the Earth is a sphere (more-or-less). Its own gravitational pull has forced it into that shape to ensure a pretty even distribution of mass. In order for another object to exert an appreciable torque on the Earth, there would need to be something for that force to grab onto - a major inequity of mass distribution. But there isn't one. There just isn't.

Of course there is some effect that the moon has on the Earth with its tidal forces, but that effect is so small it takes millions of years to become noticeable. The only reason we know about it at all is through very precise measurements using lasers bounced off reflectors on the moon's surface.

And, as mentioned in the previous point, these alignments have happened millions of times in the Earth's history. This effect has never happened before... why would it happen now?

Okay, but there was another aspect to this whole "alignment" thing - the alignment of the Earth with the centre of the galaxy or something. What does that even mean?

The thing is this: if you take any two objects and draw a line between them, they are aligned. By definition. So yes, the Earth will align with the centre of the galaxy in 2012... because it's aligned with the centre of the galaxy all the time. Even right now! Oh noes! It's an alignment! Run!

But Betelgeuse Will Explode!

This is a fairly new one. In the last couple of weeks there's been a news story circulating through the mainstream media that the star Betelgeuse will explode in 2012, fulfilling the Mayan prophecy.

Okay, so what's the deal here? Will Betelgeuse explode? Yes. Betelgeuse is a red supergiant star, one of the largest and brightest stars known, and in the top ten brightest objects in the sky. If you look at the constellation Orion, you'll notice that the star on his left shoulder has a reddish glow... that's Betelgeuse.

Red supergiant stars are stars many times more massive than our Sun that are nearing the end of their lives. They've spent most of their nuclear fuel and lost a lot of their mass... their gravity isn't strong enough to balance out the energy produced in their cores, so they puff out to many times their previous size. This is the last stage in a star's life before it explodes in a spectacular Supernova.

Will Betelgeuse explode in 2012? Maybe. The red supergiant phase of a star's life typically lasts for about a million years or so. The problem is we don't know if Betelgeuse has just entered the phase, or if it's been in that phase for a million years already. We just can't tell at this point. So, the odds of Betelgeuse going supernova in 2012 are around one in a million. If you want to narrow that down to the day, the odds of Betegeuse going supernova on the 21st of December 2012, that's about one in three hundred and sixty five million. You have way better odds of winning the lottery on that day.

When Betegeuse explodes, will it cause the end of the world? No. Paleontologists do theorise that some of Earth's mass extinctions in the past may have been caused by nearby supernovae, but Betelgeuse isn't close enough to us to pose a threat. Betegeuse is, however, close enough to give us a brilliant show. When it does blow, it'll likely be comparable in brightness to the moon, and may even be visible during the day.

Okay, So There Will Be Some Sort of Spiritual Change in 2012

Spiritual Person - Probably

This is an amusing claim. What's happening here is that some of the former doomsday prophets have started to see holes in their own prophecies. They recognise that when the 22nd of December 2012 rolls around, and the world didn't end, they'll have a lot of explaining to do. So they're backing away from making hard, testable claims, and instead are softening their predictions.

One that I've heard several times is that there will be some sort of "spiritual change" or "shift in consciousness" on that day, that will somehow have lasting consequences that may not be felt immediately. You see what they did there? They've made their claims so vague and wishy-washy that they've become completely untestable - in fact, they've become entirely meaningless. They can't offer evidence to support their claims, but also we can't disprove them.

These sorts of claims are what we like to call "not even wrong". They're just not sophisticated enough to even examine critically. So sure, there may well be a spiritual change or consciousness shift on that day... whatever those things mean. But you can make the same claim about any other day, and be just as right, wrong or not even wrong.

So Then What?

Since none of these predictions are likely to bare any fruit, I'm willing to offer a prediction of my own. December 21st 2012 will be a day like any other: the sun will rise, the sun will set. The tides will go in and out. People will die, others will be born. Just like every day before it, and every day after it. I, for one, will probably spend that day thinking about the fact that it's the summer solstice here in the Southern Hemisphere, and probably doing some Christmas shopping. Care to join me?