A blog explaining science and technology through the movies ... or explaining the movies through science and technology, depending on the point of view. English is not my first language, so I apologize for the mistakes you are likely to find in the posts

Wednesday, September 27, 2006

Waterworld: ice flows to the sea

In 1995 Kevin Costner, directed by his namesake and friend Kevin Reynolds, got a half success / half failure with the pretentious and very expensive film Waterworld. The movie’s plot consisted of melted ice caused by the greenhouse efect raising the level of the sea until drowning the whole Earth mainland.

Global heating is produced by the burning of those known as fossil combustibles’ (coal, oil and any other one with an organic origin): combustion produces CO2, a gas that seems to prevent the sun's heat leaving the Earth again, warming the planet like the glass in a greenhouse (that’s where the name comes from).

In the ten years that have gone since Waterworld, climatic change is seen as more and more of a threat: nevertheless, exageration in the movie is obvious, since the amount of ice existing in the planet isn’t at all enough to cover the Earth. Scientists consider that melting all the ice in the poles would ‘only’ increase the level of the sea by about 70 metres, which means that cities like Madrid and many others wouldn’t even notice it, most of the Earth would still be as dry as it is now.

That doesn’t mean global warming and ice melting shouldn’t be considered as a noticeable risk. Melted ice is fresh water and would cause a drop of the salt level in the sea which could bring important disturbance in sea life. But that would be the least important thing compared to changes in weather brought by a warmer planet with a cooler ocean.

This last point is very dangerous because it is simply imposible to predict its consequences. Weather isn’t ruled by well known laws but is chaotic (and we will talk much more about chaos theory in the future), so that neither can we see what will happen, nor can we avoid it. All the hurricanes and natural disasters that have been going on lately in places where these kinds of phenomena were unknown are giving us a ‘little’ advice about what could happen. Even when we won’t end up with gills as in Waterworld, we’d better take it seriously.

Saturday, September 23, 2006

Signs: Hydrophobic extraterrestrials, go home!

In the large list of extraterrestrials invading the world in science-fiction history, those of Signs, the M. Night Shyamalan film from 2002, find themselves among the most incredible because of their allergy to water, which can be suspected along the film and gets confirmed in the end, giving the key for expelling them from our planet.

Life away from water happens to be not impossible but quite difficult to take into consideration for most scientists. If it existed, it would be a sort of life very different to everything we know: water is an essential compound in chemistry due to its neutrality (lack of acidity or alkalinity) and also because it is a universal solvent. Actually, a key point in the search for present or past life on Mars is making clear if liquid water is, or was ever, present on that planet.

Therefore, it seems strange to think of a living thing allergic to water, and much stranger in antropomorphic beings like the little martians from Signs. Nevertheless, even when there could be forms of life, not only not dependent of water, but also hurt by it, it is not at all possible they could invade the Earth.

Apart from the well known fact that three-quarters of the Earth is covered by water, the air we breath is made of water to some extent, a considerable extent actually, as we all get to appreciate the difference between wet climate, in which the air contains more water, and dry climate.

Not only could a hydrophobical extraterrestrial never get wet, then, but the very slight contact with air itself would hurt him: space suits would become indispensible. In any case, their allergy to a compound as common as water would become obvious as soon as they set foot on the planet. No way would they be able to conquer any territory before humans found so easy a way to get rid of them. Others, beside, would find out much earlier than the family in the film, which were good fellows but a bit simple-minded....

Thursday, September 21, 2006

Magnolia: It's raining frogs

Those who have seen this interesting movie by Paul Thomas Anderson (1999) probably remember the surrealistic scene in which thousands of frogs rain all over the city and the perplexed and tortured characters. All right, taking apart their metaphorical qualities, rain frogs are a rare but real phenomenon which we are able to explain scientifically.

Atmospherical pressure inside a twister is so low that a vacuum is produced, bringing a suction effect similar to that of a very strong domestic vacuum cleaner. If this takes place in a pool full of frogs, these will see themselves sucked in and taken up in the air: later, when the twister loses its energy and can’t thwart gravity effects anymore, they will fall down “raining” all over the place, which could be many kilometres away from their natural habitat.

A rain so intense as the one in the movie might not be possible and neither a so pure one, because other animal, plants and objects being in the pond at the moment would rain along with the anphibians. Nevertheless, it is logical that no water rains, as it gets easily sprayed and scattered by the twister, and later evaporated into the atmosphere. Those who still find it hard to believe can read about some real frog rain news in the following links:

About Dracula's blood group

Vampires lick blood no matter when, no matter from whom, in a promiscuous way. Mortal men have to be more selective about it, since getting blood which is incompatible with ours can be extremely dangerous; except for a few of us gifted with a natural condition allowing them to be vampires ....

When Bram Stoker wrote his novel Dracula in 1896, medicine was starting to test blood transfusions. When blood from another person was introduced into a wounded man or woman’s body, the patient's condition sometimes improved quickly in a remarkable way: there were other times, though, when he died just as fast. No explanation to this was found until blood groups were discovered in 1900, four years after the book was published.

Therefore, neither Bram Stoker, nor his creature could know anything about the subject; that’s why when Dracula starts biting and drinking Lucy’s, her first victim at London’s, blood, doctor Van Helsing cures the girls with the brand new technique of transfusions, taking no less than four different men as donors. In real life, this treatment would have killed poor Lucy much faster than Dracula’s bites unless she had the vampire’s blood group, AB positive, known as the universal receiver, or unless all his donors belonged to the O negative or universal donor group.

Why is this? What is known as blood groups A and B happen to be two proteins sometimes found in blood. Those who have one of them are A, those who have the other one are B, those who have both are AB, and those lacking both are O. In addition to this, there is a third protein known as the Rh factor: if it is there, we speak of Rh +, and otherwise, when it’s not there, we speak of Rh-.

If someone lacking one of those proteins gets any of them in a transfusion, his or her body will react against this strange component causing death. Which means that an O person can only get blood from other Os, an A can get it from either another A or an O, and an AB can get it from anyone, as he has all the components in his blood already. Those who are Rh- can give blood to anyone, but only get it from other Rh-. Vampires, therefore, are either AB +, either aware of seeking O- necks.

King Kong and Godzilla: Size does matter

Would the existence of King Kong be possible, a gorilla of such size climbing skyscrapers agily? It seems that science, a usual wet blanket for the movies, says no.

We are used to thinking proportionally: if a book costs five euros, two books cost ten euros; if going to this city by car takes three hours, going somewhere three times as far takes nine hours. We might think, therefore, that a gorilla twice as high as those which we are used to see would have head and feet twice as big …. But I’m afraid the scale thing isn’t that easy.

The body of a person or an animal could be considered as a frame similar to that of a building. The bones, those of the legs especially, play the role of supporting pillars. Since the material forming the frame is always the same (all humans and animals are made of flesh and bone … well, with the few exceptions of those including silicone and botox), the weight carried by the legs / pillars depends only on the volume, the bigger the size the bigger the weight.

Well, the pillar being able to support the weight or breaking under it depends on the weight it is able to carry by unity of surface. If the weight doubles, the legs’ width must double too. And there is the problem regarding the scale: if we take a normal gorilla and make its size ten times bigger to turn him into King Kong, his weight won’t grow at the same rate his surface does, but considerably faster.

That’s just a matter of maths: weight depends on volume. If we make body’s height, length and width ten times higher (in order to preserve the same proportions) weight gets 10 · 10 · 10 = 1000 times higher. Nevertheless, the legs bone's surface, which is bidimensional, only gets 10 · 10 = 100 times higher. A leg only 100 times bigger is supporting a body 1000 times bigger, so it turns 10 times weaker. The consequence is King Kong or Godzilla wouldn’t scare anyone, as they would crumble victims of several fractures the very same moment they would stand up.

This is even worse for insects and arachnids, the slim legs of which have to support exoskeletons (external backbones) too rigid and heavy for their size. That’s why invertebrate animals are quite limited in size: if they were bigger they would get their legs constantly fractured. Movies like Them! and others dealing with giant ants and bugs don’t happen to be very plausible.

The only viable solution for King Kong, Godzilla or The 50 ft women would be ruining their proportions and getting very much longer than tall. Their surface area would grow at the same rate as their weight this way, so that their feet would be able to support them. Of course they would be less photogenic, they would look more or less like this; the scope and the screens should be modified to watch them properly …. Size does matter!