Monday, 3 July 2006

Don't always believe what you see at the movies

We’ve all watched films and thought, "that’s impossible" or "that’s unbelievable". Sometimes movies take liberties with science, allowing things to happen that in real life are impossible, or at least unknown. Today we are going to have a look at three of my favourite science fiction films and see whether or not some of the astounding things that happen in them have any scientific basis.

The Matrix:
One of the most popular science fiction films of recent years is The Matrix, in which Keanu Reeves discovers that artificial intelligence has trapped human kind in a virtual world and is using it as a power source. There are so many interesting and baffling scientific and ethical questions raised in this film that there are thousands of Internet pages and chatrooms devoted to the topic.

One of the scientific problems with the film is the notion that the machines are using humans as a power source. Morpheus says to Neo that the human race is enslaved in a power station, where it is used as a source of bioelectricity. This is, unfortunately, rubbish as it violates the law of conservation of energy. This is because humans need to eat to stay alive, and the conservation of energy law states that the amount of energy that comes out from the humans can not be greater than what is taken in, making the power station ludicrously inefficient. Also, in Morpheus’s speech to Neo, he states that the machines have discovered a new form of nuclear fusion – obviously their actual source of energy, and not the humans. However, this in itself provides hope for those who believe in the Matrix universe. Controlling the fusion reaction is a difficult process that requires computer control. One theory suggests that hooking up millions of human brains creates an outstanding parallel computing system that can act as an immense distributed processor for controlling the nuclear reactions.

The movie Contact sees Dr Ellie Arrow, played by Jodie Foster, searching the heavens for electromagnetic signs of extraterrestrial life using radio telescopes, eventually finding a signal and using that signal to build an immense machine that transports her, through a worm-hole, to the Vega star system where she speaks with an alien and then comes home. The movie is based on the novel by Dr Carl Sagan, an American astronomer, astrobiologist, and highly successful science communicator. There are many people in the world today doing as Dr Arrow did in the film and search the sky for signs of intelligent life – where the movie takes a leap is that in real life, we have yet to find any. You can even sign up to SETI at home and donate some of your computing power to analysing signals that come in from radio telescopes around the world.

Sagan wanted to make his novel as close to scientifically accurate as possible – obviously difficult to do when dealing with such mind-blowing topics – so he contacted the world’s foremost black hole expert, Kip Thorne of Caltech. Thorne and associates were able to postulate a theoretical set-up for a transversable wormhole using “exotic matter.” To be stable, wormholes need lots of what’s called negative energy. Quantum mechanics suggests that it exists, but we haven’t found it yet, and we don't know whether the laws of quantum mechanics allow enough negative energy to be concentrated to allow wormholes to exist. One possible location for wormholes is at the centre of black holes. Travelling through one of these might prove extremely difficult however, since the wormhole would be so unstable that it would collapse as soon as a spaceship (or even a ray of light) entered it. This is because there would not be enough negative energy to hold it open.

Jurassic Park:
In Jurassic Park, Richard Attenborough and researchers find fossilised mosquitos that had bitten living dinosaurs. Soon after, these insects were caught in oozing tree sap that fossilised into amber. The scientists extracted the dinosaur blood from the fossilised insects and used the DNA in the blood to recreate dinosaurs.

Does amber old enough exist? Not from the Dominican Republic, where the sap in the film is from. The amber from this island is between twenty and forty million years old, far too young for the last dinosaur who existed sixty five million years ago. There are however, a number of sites around the world where amber old enough can be found. But even if it exists, can we extract DNA from an insect trapped inside? Unfortunately it appears to be virtually impossible to extract sufficient DNA to recreate a dinosaur genome. Research has shown that the DNA of dead organisms begins to fragment very rapidly unless it has been preserved under unique conditions. If a piece of amber were found containing an insect full of dinosaur blood, the blood cells would have to be separated from the insect’s cells, difficult in itself. Next, scientists could use a technique called polymerase chain reaction (PCR) to replicate the DNA enough times to work with it. But since DNA deteriorates over time, very little of the complete genome would be left. The genome of a dinosaur is made up of billions of nucleic acids, and we may be only able to string together two or three hundred of them, or less than one millionth of the genome. This gives us no clue as to the rest of the genome or how it all goes together.

But don’t give up on movie science just yet. I’m interested in seeing how the new Spiderman movie deals with Spiderman’s special new powers that he gets from the moon, and how the villains get their powers.

More on the science of The Matrix
More on the science of Jurassic Park

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