The sci­ence of the sun

Country Life Every Week - - My Favourite Painting Peter May -

• The colours of sun­rise and sun­set re­sult from a phe­nom­e­non known as scat­ter­ing: mol­e­cules and small par­ti­cles in the at­mos­phere change the di­rec­tion of light rays, caus­ing them to scat­ter, which af­fects the colour of light from the sky, de­pend­ing on the wave­length of the light and the size of the par­ti­cle. Short-wave­length blue and vi­o­let are scat­tered more than other colours; long-wave­length red is scat­tered least. At sun­rise and sun­set, the light passes through more air and more at­mos­phere, so there are sim­ply more mol­e­cules to scat­ter the vi­o­let and blue away • Ma­jor vol­canic erup­tions scat­ter par­ti­cles of gas, dust and ash into the up­per at­mos­phere, which can re­main for sev­eral years. The ef­fects in­clude spec­tac­u­larly mul­ti­coloured sun­sets, with more per­ceived reds, pur­ples, pinks and or­anges than nor­mal • Sun­sets tend to look more chaotic, with large cur­tains of colour. Sun­rises tend to have a cleaner and neater over­all look • ‘Red sky at night, shep­herd’s de­light’ or so they say—but why? This oc­curs when the weather pre­dom­i­nantly comes from the west, as it does in Britain. A red sky at night means high pres­sure is mov­ing in from the west and the next day will be sunny. A red sky in the morn­ing sig­nals that high pres­sure has al­ready moved east, giv­ing way to low pres­sure with wet and windy weather— ne­ces­si­tat­ing that shep­herd’s warn­ing

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