Having now seen (and been highly amused by – such is my perverse sense of humour) Mr Roland Emmerich’s latest blockbuster disaster movie[1], 2012, in which civilisation as we know it – and billions of people – succumb to, inter alia, super-volcano eruptions, earthquakes, tsunamis and mega-floods, I find that – although my admiration for the ancient Mayan’s knowledge of astronomy, and their calendrical achievements, is undiminished, the film did stretch one elastic of my credulity well beyond breaking point.
For, at the very beginning of the film, one of the leading characters (whose name I forget – and it scarcely matters), played by the fine British Shakespearean actor, Chiwetel Ejiofor (a very good Othello, if memory serves), discovers, through his friend, an Indian particle physicist, working in a laboratory deep below ground in a copper mine somewhere in the sub-continent, that the Sun’s neutrino flux has increased, and that the neutrinos are changing into different sub-atomic particles when they reach Earth (what kind we’re not told), causing the Earth’s core to heat up.
Now, that the Mayans could have worked out the world would end on
This would require a knowledge of quantum flavour dynamics (QFD, or electro-weak theory) – and of the existence of neutrinos in the first place – and of solar neutrinos in particular, ergo of the thermonuclear fusion process that powers the Sun. It would require that knew that neutrinos had mass, and that there were three kinds of them – electron neutrinos, muon neutrinos and tauon neutrinos, with their respective anti-particles.
All of this is, of course, completely impossible. The Mayans may have been smart, but they were not that smart. (And, what’s more, they, like the Aztecs of Mexico and the Incas of Peru, had a nasty habit of indulging in human sacrifices to their gods.) So, could solar neutrinos actually heat up the Earth’s core?
Well, there are an awful lot of them. The solar neutrino flux incident upon the Earth’s surface is approximately 6.2965 × 1014 m-2 s-1, which means that every square metre of the Earth’s surface is being bombarded with 629.65 trillion neutrinos every second! See: http://www.cosmicrays.org/muon-solar-neutrinos.php.
The energy of one of these solar neutrinos could be as high as 18.8 MeV (= 3.012 × 10-12 J), so, in theory, at least, the irradiance from that 629.65 trillion neutrinos per second could work out at ~1.9 kW m-2. In practice, however, neutrinos tend to be far less energetic than that – between 425 keV, for the proton-proton I reaction, up to 15 MeV for the ‘boron 8’ neutrinos and only 18.8 MeV for the rare ‘hep’ neutrinos (an energetic side-chain of the proton-proton, or ‘pp’ reaction, called the pp IV reaction, in which He-3 is converted into He-4 with the addition of one proton, or hydrogen-1 nucleus, and the release of a positron and an electron neutrino)[2].
Furthermore, neutrinos only interact very weakly with other matter. They have no electric charge, only a very small mass and only take part in gravitational and weak force interactions. They pass through us on their way to the Earth’s core, so if they were going to heat that up, they would certainly heat us up first!
Of far greater significance, in terms of the Sun’s energy output, is its photon flux, across the entire electromagnetic spectrum. The average amount of electromagnetic radiation from the Sun distributed over the entire surface of the Earth is approximately 342 W m-2, which works out at ~10.785 GWh m-2 yr-1. It is this that keeps us warm, although were it not for the beneficial impact of the greenhouse effect (and there is one!) we would still find our climate very chilly indeed[3]. The trouble is, we are now having too much of a good thing, by putting too much warming CO2 (and other greenhouse gases) into our atmosphere – a bit like leaving the electric blanket on for too long. Not good for the electricity bills – and a fire risk!
So, planetary alignments with the Sun (or the Earth) notwithstanding, I think we are quite safe on the Mayan Long Count end date. The Mayans did not, in any event, believe that the world would end then – their conception of time was, like that of a lot of other ancient peoples, cyclic, so it wouldn’t have made sense to them to speak of the world ‘ending’. There is nothing unusual about the alignment of the planets on the 21st December, 2012, as this picture of the inner solar system on that date (and at the required time of the Winter Solstice in the Northern Hemisphere, 11:11 GMT) shows:
–Venus and Mercury are aligned, but Earth and Mars are not. In case anyone should think I am indulging in selected reporting of the evidence, here is the entire Solar System at that day/time:
– the size of the inner planets is greatly exaggerated, as is the size of Pluto (which no longer counts as a planet, alas!). To obtain the information for yourselves, see the website at: http://www.fourmilab.ch/cgi-bin/Solar/action?sys=-Sf.
However, do go and see the film. The apocalypse that may be heading our way may not be a Mayan one, and it may be somewhat later than 2012 (if not by much – say, 2030, or thereabouts), but we may at least be entertained by the spectacle of John Cusack escaping near-certain death while we wait for it!
[2]See: http://en.wikipedia.org/wiki/Standard_Solar_Model;
[3] Possibly as low as –18°C (–0.4°F). See: http://en.wikipedia.org/wiki/Greenhouse_effect.
No comments:
Post a Comment