YPS Magazine

ISSUE: 2004, Volume 1, Issue 3

Science Shorts

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Red Sky at Night

by David Humphreys, USA

Signs in the sky have long been used for weather predictions. About 2000 years ago the Gospel of Matthew records an ancient version of the rhyme many of us learned as children,‘Red sky at night, shepherd’s delight; red sky in the morning, shepherd’s warning’. A red sunset is often seen when the western sky is especially clear. The colour occurs because the sun is low in the sky and its light passes through the additional atmosphere. The colour is enhanced if a stable high pressure region is present. The reason for this is that high pressure suppresses cloud formation and holds air pollutants near the earth. These pollutants further scatter the colours of sunlight, enhancing the reddening effect in the west. Since high pressure generally brings good weather, red skies in the evening often indicate that fair weather is approaching from the west. On the other hand, if the red appears in the eastern morning sky then the high pressure system has already passed through. Since lower pressure usually follows a high pressure system, and is often associated with unsettled weather, red sky in the morning can indicate stormy weather. Evening redness can be caused by sunlight reflecting from a cloud layer retreating in the east and morning redness may be due to reflection from an advancing cloud layer.

So next time you hear the ancient rhyme about the red sky, don’t dismiss it altogether, it may well predict tomorrow’s weather. We often use a variety of clues to give us an insight about future events. Like the quote about the red sky, sometimes these are sayings which have been based on years of observations in nature. At other times the clues we use are based on speculation,myth and superstition.So we need to ask what kinds of claims can actually help us know and prepare for the future.Often-times science has been pitted against religion in these matters. Science is based upon observation of events, the association of cause and effect, the discovery of laws which the world and everything in it obeys. Because science is concerned with explaining the universe, it attempts to provide details of the mechanisms by which things come to be. By using experiments, wherever possible, scientists undertake to replicate past results. They are in pursuit of scientific evidence for their claims and on this basis offer predictions of future events. Yet science is not in the business of answering the ‘why?’ questions. Nor is science the only sphere for answering questions about the future. Yet in the western world we are fairly dependent on accepting scientific knowledge as the sole arbiter of truth. While science may be able to tell us the truth, it may not be able to tell us the whole truth. Moreover, just because something is not scientific it does not mean it is not true. Science has value but it does have its limits. Do you believe that science can answer all the important questions of life? What kind of questions can science not answer? And where do you turn to find answers to these questions?

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