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Category Archives: Science

That would’ve made an arresting headline, wouldn’t it? Well, guess what, Star Wars fans – it really happened. The imperial units involved weren’t stormtroopers, though; they were things like inches, feet, and pounds. It’s hard to believe, but the good folks at NASA lost the Mars Climate Observer (MCO) – a $300 million mission – in 1999 due to a failure to convert to metric units. Here’s what the Mishap Investigation Board (what a delightful understatement, by the way – to call such a screw-up a “mishap”) had to say:

The MCO MIB has determined that the root cause for the loss of the MCO
spacecraft was the failure to use metric units in the coding of a ground
software file, Small Forces, used in trajectory models. Specifically, thruster
performance data in English units instead of metric units was used in the
software application code titled SM_FORCES (small forces). A file called Angular
Momentum Desaturation (AMD) contained the output data from the
SM_FORCES software. The data in the AMD file was required to be in metric
units per existing software interface documentation, and the trajectory modelers
assumed the data was provided in metric units per the requirements.

Besides being a redeeming story that you can triumphantly relate to the old math teacher who castigated you for every careless mistake, this incident does also evoke some worrying thoughts. Yes, we all make mistakes, but most of us aren’t in a position to cause a spacecraft to careen out of orbit to crash into a planetary surface. A lot of scientists, though, have access to a lot of things that – well, are capable of creating quite a big bang. What if someone had screwed up the insertion of a satellite into geostationary orbit around the Earth, for instance?

I’m not the sort who likes to foment panic about the dangers of rapidly advancing technology, and I suppose we’ve been pretty lucky so far. The LHC did not create a black whole that swallowed up the Earth, the National Ignition Facility in California did not set the atmosphere ablaze, and no nuclear power plant has turned out to be nuclear bomb (although I suppose the government of Iran may want to change that). But it is interesting to note that as our knowledge expands, our inimitable sense of curiosity becomes ever more potentially dangerous. In Kurt Vonnegut’s novel Slaughterhouse Five, a race of extraterrestrials called Tralfamadorians cause the extinction of the universe while experimenting with new energy sources. I wonder if a similar fate awaits us.



When I last used Hotmail (and I’ll admit it’s been a while), the service had recently added a feature that allowed you to categorize your email into separate folders. I wasn’t terribly impressed by this, because by that time I had already started using Gmail, and it was pretty obvious that Gmail’s system of “Labels” was way better than Hotmail’s folders. You can attach several labels to the same email in Gmail, but you could only put an email into a single folder in Hotmail. Well, it should be easy enough to see that some things don’t fit well into separate, non-overlapping categories.

I was recently reminded of this fact by a friend’s reaction – or perhaps more accurately, her reaction to my reaction to – the picture above, which I liked so much that I set it as my Facebook cover photo, along with a short description:

“Micrograph of stained hippocampal tissue. The hippocampus is the component of the brain that’s primarily responsible for the formation of new memories (Leonard Shelby, the guy in “Memento” developed severe anterograde amnesia after sustaining damage to his hippocampus – and yes, that can really happen). The pink parts are the neuron cell bodies, the blue fibers are axons, and the green fibers are supporting glial cells (which outnumber neurons 9 to 1).”

My friend pretty much told me that it was a pretty picture, and that was cool, but that it was pretentious and unnecessary to see it as anything more. Well, I disagree, but not entirely – because I do think it’s a pretty picture, but it’s also fascinating because of what it represents.

When you look at that picture, you are looking at the hardware that lay behind what was once a human mind. It’s easy to forget this, but everything that matters to you only really exists within the confines of a tiny region of the universe that you perceive as your skull. We forget this because we forget that there is hardware behind human minds. The universe is made up of various types of waves and particles – there are no sights, sounds, or smells, let alone emotions or experiences. Those things are “virtual” constructs; created by the hardware of the brain and handed on a silver platter to your consciousness – which is also, of course, created by the brain.

Every beautiful piece of music you’ve ever heard, every exhilarating game of football you’ve played, every romantic experience you’ve had, is an outcome of the (currently) mysterious interactions between billions of neurons like those in the picture above. Somehow, somewhere in that mess of molecules are things like a picture of a human being that you recognize as yourself; records, or “memories”, of the activities of entirely different groups of molecules that belonged to you a few years ago; and a whole lot more. It’s an amazing, awe-inspiring thought. And the picture up there is so much the prettier for the fact that it evokes these thoughts.

As a little bit of a contrast, take a look at the picture below, a diagram showing the structure of an animal cell.


Beyond all doubt, the ways in which cells go about their jobs is absolutely fascinating, but this picture just isn’t as aesthetically pleasing as the one above, is it? So, by thinking about the two pictures, we can conclude that things that are intellectually stimulating are a separate category from things that are are aesthetically pleasing, but that the two sets are not mutually exclusive.

In short, we should’t be forced to put awesome things into non-overlapping folders like “Aesthetically Pleasing Pictures” and “Sciency Stuff”; instead, we should be able to attach both those labels to an experience, and see it as even more awesome!

Based on the overwhelming success of this blog’s last competition (a grand total of 1.5 entries, one of which was mine), I’ve decided to launch a new one. Without further ado, here’s the brief:


Contestants must come up with a marketing slogan/tagline for some kind of physical phenomenon, as though it were a product that could be sold to customers.

Marks will be awarded for:

– the degree to which phenomena are related to actual products/taglines/marketing stereotypes;

– the ability to highlight obscure phenomena or to present a novel view on more commonplace phenomena;

– and finally, for humour, too. 


The prize? Get ready for this: the winner gets… to laugh at the losers. No, seriously!

Anyway, since my entries are likely to be the only ones, I’ve decided to come up with three. Here they are:

Oh, I would SO buy that.


Hmm, there's gotta be a catch. Usually it's the unreliable products that have long warranty periods...

And finally, my favourite:

For a short explanation of how optical interference makes bubbles pretty, click here.

For details on the proton-proton chain reaction and on Cherenkov radiation, click here, and here respectively.


We all know that the Ancient Greeks thought everything in the universe was made up of four indivisible elements: Earth, Air, Water and Fire. And we all snigger superciliously at their ignorance, because we all also know that Earth and Air are mixtures, pure Water is a compound, and Fire is – wait, what is Fire?

If you were ever curious enough to ask that question, there is a significant chance that you received one of the following incorrect answers:

1. Fire is pure energy. I always found it pretty hard to wrap my head around this idea. I mean, what exactly is “pure energy”? Mass times the speed of light squared?

Well, okay, I suppose light and heat could plausibly be suggested as being forms of “pure energy”, but they both can be understood in terms that go a bit further that just “pure energy”. Light is often well described as an electromagnetic wave, and heat can be described as the stored kinetic and potential energy of atoms and molecules. In contrast, if we called fire “pure energy” and just left it at that, we would really just be saying that we had no idea what it was.

2. Fire is a plasma. This answer isn’t actually necessarily wrong – fire can create a plasma. However, the fires most of us think of when we ask the question (candle flames, forest fires, burning buildings, Molotov cocktails, etc) almost never do create a plasma. You can be pretty sure of this because these ordinary fires are not affected by electricity or magnetism. A plasma – an ionized gas – would be affected by both.

Now that we’ve got those out of the way, let’s look at the correct answer to the question What is Fire?

Fire is a mixture of incandescent matter. 

Nice, simple, one-line answer, isn’t it? I wanted to give you that right up front, so you don’t get a little distracted by some of the complicating details we’ll go into next.


Here’s the first of them. A fire can exist only in the presence of these four ingredients: heat, fuel, oxygen and a chain reaction. The fires you see around you are nearly all created during a combustion reaction between an organic compound (the fuel – an example would be the butane in your lighter) and oxygen. However, these reactions don’t usually start spontaneously – you need to provide heat to the fuel-oxygen mixture to get them started. Once the reaction gets started though, it often releases enough heat to keep itself going until all the fuel/oxygen is used up. Thus, a chain reaction keeps the fire going.

The four key ingredients in any fire are eloquently summed up by the following diagram, called the fire tetrahedron:

We now know much more than we did when we first asked the question. Here’s a quick interim summary: Under special conditions, a fuel/oxygen mixture reacts in a self-sustaining way to release incandescent matter (both gases and un-combusted solids like soot) that we perceive as fire. There’s just one last thing we need to clear up: what exactly does incandescent mean?


Once again, let’s keep things simple. We’ll start with the fact that anything that has a temperature above absolute zero (0 Kelvin, or -273 degrees Celsius) is emitting electromagnetic radiation in a process called thermal radiation. Why? Because all matter consists of charged particles (e.g. electrons and protons), and when you accelerate a charged particle, it gives off electromagnetic radiation (see Larmour Formula).  So who’s accelerating the atoms? The temperature is – when a body gains heat, its atoms/molecules begin to move about randomly (in fact, this is part of the definition of temperature), bumping into one another, and thus causing acceleration of charges.

Right, so everything around you is emitting thermal radiation in some area of the electromagnetic spectrum. The point I’m trying to get to is that some of that thermal radiation is in fact sending out visible light – and that is called incandescence. Tungsten filament bulbs work by heating tungsten to the point where its thermal radiation is in the form of visible light – i.e., by incandescence. (By the way, fluorescent lights work in a very different, and fascinating way, but let’s save that story for later). The flames in ordinary fires also give off light through incandescence.

Well, there you have it. Fire is a mixture of incandescent matter. You may now go back to mocking Aristotle.

Oh, one last thing, though: a little treat for having stuck around this long. Below is an image of a candle in space. As you’ll notice, it’s flame is pretty different from the ones we’re used to. It’s perfectly spherical, because in microgravity, there’s no “up” for the hot gases to go to, and they spread equally in all directions.

In a microgravity environment, a flame is spherical in shape

It is probably wise to exercise a great deal of caution in using treatments such as electroconvulsive therapy (see Messing With Memory) that are essentially mysterious to even the people administering them. But, of course, not many people undergo ECT anyway. Homeopathy is a much more prominent example of a family of treatments of this nature. Please read the following very carefully:

If homeopathy does work, it works through some unknown mechanism that is completely foreign to our present understanding of physics and chemistry. In other words, if the laws of physics, as they stand today, are correct, then homeopathic medicine SHOULD NOT work.

Please follow this link to read a brief summary of the basic tenets of homeopathic medicine; and ask yourself seriously whether it is advisable to build ostensibly scientific theories of disease that are based on vague, undefined (and possible un-definable) terms like “the vital force of an individual”.

Consider this definition (from here) of “dynamization” – the process through which homeopathic remedies are prepared:

Dynamization: The process of increasing the vital energy, and thus the potency, of a substance through specific forms of serial dilutions, termed “succussion” or “trituration”.  Dynamization is the goal of remedy production.  It is the most characteristic aspect of homeopathy. 

Ask yourself, again: what is the “vital force” of a substance? And how could it increase when there is less of a substance in the solution? Chemistry does not normally work this way.

Having said all that, I must also note that it would be wrong for anyone to be biased against homeopathy. What this means is that if there is convincing evidence that homeopathy works, then even the most committed skeptics  must honour that evidence and adjust their beliefs about homeopathy. The fact is, though, that the evidence is missing. The following is from a 2002 study published in the British Journal of Clinical Pharmacology:

Eleven independent systematic reviews were located. Collectively they failed to provide strong evidence in favour of homeopathy. In particular, there was no condition which responds convincingly better to homeopathic treatment than to placebo or other control interventions. Similarly, there was no homeopathic remedy that was demonstrated to yield clinical effects that are convincingly different from placebo. It is concluded that the best clinical evidence for homeopathy available to date does not warrant positive recommendations for its use in clinical practice.

You will find many more studies like that if you look for them.

In sum, then, there are two crucial differences between ECT and homeopathy: first, although we do not know how ECT works, we have no reason to believe that it goes against what we already know about the brain; the same is not true of homeopathy, because the effects it claims to produce are in direct contravention of what we know about physics and chemistry. And second, there is no convincing scientific evidence that homeopathy does anything more than a placebo would; whereas there is real evidence for the therapeutic value of ECT.

Remember how there’s a spell in the Harry Potter novels that allows you to erase someone else’s memories (I think you’re supposed to say “obliviate” when you cast it)? Well, it turns out that, once again, boring old Science has proved itself capable of replicating the effects of Magic. To some extent, anyway.

You may have heard of electroshock therapy; and you probably pictured something like this when you did hear of it:

Electroconvulsive Therapy - Frankenstein's legacy?

But the truth is, electroconvulsive therapy (ECT), as it’s known today, isn’t really that dramatic, and usually doesn’t require a murderously deranged doctor.

ECT is a psychiatric treatment that’s used to relieve the effects of some kinds of mental illnesses (including, prominently, severe depression). As far as I can tell, ECT is almost as simple as it looks: you hook up a few wires and induce a few seizures by passing electric currents through the patient’s brain. But before you let your imagination run away with you, note that the patient is under general anesthesia, is given muscle relaxants to prevent major convulsions, and the currents are usually tiny.

Although it’s great that people often feel a lot better after ECT, it’s a bit scary to think that no one knows why or how it works. We do know, of course, that electrical currents passing along neurons are part of the foundation of how the brain works; but that doesn’t explain why a sudden shock to a generalized area of the brain should relieve a wide variety of symptoms.

Anyway, here’s the interesting thing: experiments with patients who’ve received ECT have found that they often incur amnesia after the therapy, sometimes forgetting things as far back as a few years. This would be horrible if not for the fact that this kind of severe amnesia following ECT is almost always temporary – the lost memories usually do return in a few days or weeks (again, how this might happen is a mystery).

However, there are a few memories that usually do not return: those of events immediately before and after the administering of the ECT. And that’s what you use as a Memory Charm. This could, of course, be of immense practical value. For instance, so long as you’re quick about it, you actually can get that certain someone to forget something extremely embarrassing that you do in front of him/her.

Now if only we could fit ECT apparatus into a little wand-shaped thingy…

Could "Minority Report" become reality?

Well, it’s probably not terribly likely that things’ll go that far, but consider this:

“There has been a long controversy as to whether subjectively ‘free’ decisions are determined by brain activity ahead of time. We found that the outcome of a decision can be encoded in brain activity of prefrontal and parietal cortex up to 10 s before it enters awareness. This delay presumably reflects the operation of a network of high-level control areas that begin to prepare an upcoming decision long before it enters awareness.”

That’s from a paper published in Nature Neuroscience (you’ll find it here) in which the authors used functional MRI scanning to peer into subjects’ brains as they were making the (rather simple) decision of whether to click a button next to their right hand or their left hand. And as they say in that quote from the abstract of the paper, the researchers could predict which hand would be used, up to 10 seconds before the subject himself became aware of his final decision.

That’s a little scary isn’t it? I mean, what if there comes a time when there are remote fMRI scanners that can be pointed at anyone to see what they’re about to do in the future? What if you’re snatched out of your bed and thrown into prison for a crime you don’t even know you’re about to commit (a la Minority Report)?

Admittedly, there are a few ameliorating factors to counter the scariness of that vision. Firstly, there’s the fact that predictions can only be made about actions to be undertaken in the next few seconds; not minutes, days or weeks. So if you’re planning to assassinate a high-ranking government official, or something like that, don’t worry, they don’t have any chance of catching you until you’ve already got his head centered behind your rifle’s cross-hairs, when it’ll probably be too late anyway (good luck with that, by the way).

Secondly, the accuracy of prediction isn’t terribly impressive right now, to be honest. It was about 60% in the experiments performed for that study. And finally, decisions in real life may be infinitely more complex than “right hand button/left hand button” – and that may make them impossible to predict using brain scanners.

But this research does still raise some very interesting questions about free will. Don’t be too alarmed, though – just the fact that you’re subconscious makes a decision long before you become aware of it doesn’t in itself preclude the possibility of free will’s existence. After all, from a non-dualistic (visit this link for more on dualism) point of view, your mind is simply the firing of a whole lot of neurons, so it’s not like your neurons are holding “you” hostage.

But what if there are physical reasons (maybe something about the particular patterns of neural interconnections in a person’s brain, for instance) for why all of us make the kinds of decisions that we do? Does this mean that there may be limits to what we can think? Or what we can feel?

I hope we do find out some day.