Logarithms, Quantum Mechanics, A Fact, A Mars Mission and Plate Tectonics!

I’m a newbie to the Open University, and had my first tutorial in Taunton yesterday (I’m currently studying S283 Planetary Science and Astrobiology). It all went better than expected too, which is grand!

We went over a bit of maths, transposing equations and the like. Something I haven’t done for a while but soon got the hang of it again. Then logarithmic scales. I didn’t know things like the Richter scale (for measuring the strength of earthquakes) and decibels (the measure of sound) were measured logarithmically. For instance, a 7.2 magnitude earthquake isn’t 0.2x stronger than a 7.0 earthquake but somewhere in the region of 10x stronger (don’t quote me, or my tutor, on that). Really puts the power of earthquakes in perspective for you. Apparently during the era of Concorde the Americans didn’t want it to fly over to them, saying it was too loud. To persuade them we went over with a decibel reader. A Boeing 727 took off and from 100m away the decibel reader read 120Db’s. They did the same with Concorde, it read 130Db’s. Only 10Db’s louder they said. Well, it’s apparently 10x louder, but the Americans didn’t know it was done on a logarithmic scale. Crazy huh!

Somehow we started talking about Quantum Mechanics, something I probably never will get my head around, it’s just so darned weird! Then we moved onto how science worked itself. Facts, we learnt, are only based on observation and not tainted by theory. You cannot have a fact if it is based on theory. Odd but true. Fact: I drop a pen and it falls to the ground. Un-fact: I drop a pen and it falls towards the centre of the Earth due to the effects of gravity. In the latter case (the theory of gravity) you assume that gravity has been the same and not changed for all of time, and will not change for the rest of time, something we cannot know. Therefore it is not a fact. Very peculiar, but something we need to accept.

After a while we got onto things that were actually related to our subject and we briefly looked at the Martian crustal dichotomy. Why were the northern plains less cratered than the southern highlands? Giant impact? A huge mantle plume? Plate tectonics? No one actually knows, although the plate tectonics idea sounds most plausible to me. We discussed a manned Mars mission and about where we’d like to go on Mars, what we want to find out and so on. The orbital dynamics of getting to Mars (it’s easier than getting to the Moon apparently) the logistical nightmare about what we can do fuel wise and get the crew home. All truly fascinating stuff.

Then the Earth. Our beautiful, blue, Planet Earth and its four ‘coincidences’. A large moon, surface water, life and plate tectonics. We discussed how plate tectonics may have started (again, know one knows, it’s all speculation) and came to the consensus that the giant impact that formed the Moon is probably the most likely bet. How plate tectonics can only work with water, without it, it stops. How it ‘forces’ evolution and so on. We moved on to speculating about life elsewhere. Would they need a planet with a large moon, surface water and plate tectonics too, as well as being in the habitable zone and had suffered from a giant impact. All fascinating stuff, and something I’ll come to later on next year when we look at the Drake equation.

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This entry was posted in Science.

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