Saturday, 20 February 2010

Instant of Perception

In the core of the sun, where the plasma density is 150 times higher than the density of water on earth and the temperature is around thirteen and a half million degrees Celsius, hydrogen atoms crash into each other with such stupendous force that they fuse into helium atoms. In this process over four million tons of matter are destroyed every second, transformed into a burst of energy, the amount of which, following Einstein, can be calculated by multiplying the amount of matter by the square of the speed of light. This enormous burst of energy, in the form of high-energy photons (gamma rays) is absorbed almost immediately by the next few millimetres of the surrounding plasma, only to be released again, in random directions, at a slightly lower energy level.

The sun itself is so large that it takes this energy anything between 10,000 and 170,000 years to work its way from the core to the surface, there to be expelled as photons of light, flung off into space at (what else?) the speed of light, 300,000 km. per second. From there it takes a fraction of this energy a further eight minutes to reach our planet Earth. Striking the atmosphere, more of it is filtered and absorbed until another much smaller portion reaches the surface.

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When light strikes the retina of the eye it causes reactions in the special cellular organelles there known as rods and cones. These reactions are carried along the optic nerve into the brain, which crosses, splits and branches to deliver the signals to many areas. The signals carried along the strands of the optic nerve set a cascade of tiny electro-biochemical reactions in motion all over the brain, different neuro-transmitters being released and taken up in many millions of gaps between the synapses of individual nerve cells, a staggeringly complex dance of constantly shifting miniscule electrical potentialities surging, combining, switching. The data from the retina is analysed, classified and sorted; organised into categories, compared with experiences stored in memory, put into context with all the other signals sparking and pulsing through the brain; other perceptions, situational awareness, sensations, emotions and thoughts.

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I sit on a terrace in the early morning, a cup of coffee between my hands, looking east. I can still feel the recent lethargy of sleep slowly leaving my body. There is a beautiful sense of freshness, stillness, anticipation. In the clear morning, the horizon at the edge of the sea is a riot of blending colours from blue to every imaginable shade of red, orange and variations for which I have no name. On the line between sky and sea, a sudden orange-red thread of light. Sunrise. A moment of wonder, the first of many in another of a myriad of days.

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