Land mass, like the Asian continent in any season or the snow covered northern hemisphere in winter, is responsible for deep glowing reflection. Oceans cause relatively faint reflected light. This reflected light from the Earth, called by astronomers earthshine', and which can be seen from outer space and on photographs, can vary in brightness by as much as 20 per cent. What is of interest to scientists is that recent colour photographs show earthshine is turning from its usual brightness to a pale luminosity. What is not clear is the reason for this dimness.
Some scientists wonder if it is the global warming which is responsible.
Others speculate the cause may be the 11-year cycle of the Sun's magnetic activity. Scientists are now gathering data, a task that could very well span years, to determine what is actually responsible for the growing faintness of earthshine. Meanwhile, even the scientists are affected by the realisation that one can look at moonlight and observe the climatic condition of Earth. The stunning integration of phenomena occurring across such distances is regarded as an awesome indication of a designed purpose.