We Don't Know if We See the Same Colors

the colours that we finally think we see are labels used for convenience by the brain. I used to be disappointed when I saw 'false colour' images, say, satellite photographs of earth, or computer-constructed images of deep space. The caption tells us that the colours are arbitrary codes, say, for different types of vegetation, in a satellite picture of Africa. I used to think false colour images were a kind of cheat. I wanted to know what the scene 'really' looked like. I now realize that eve...

 The Dilemma of Human Diversity Across the Cosmos

When life spreads out and diversifies in the universe, adapting itself to a spectrum of environments far wider than any one planet can encompass, the human species will one day find itself faced with the most momentous choice that we have had to make since the days when our ancestors came down from the trees in Africa and left their cousins the chimpanzees behind. We will have to choose, either to remain one species united by a common bodily shape as well as by a common history, or to let our...

 Why Plants Evolved to be Green

why is green the dominant color of terrerestrial plants? That's easy. Chlorophyll molecules absorb light at the red and blue ends of the spectrum. It is the middle of the spectrum (the green part) that is reflected and gives plants their characteristic color. A more efficient photosynthetic pigment would be black, absorbing all colors, soaking up all the energy of sunlight, reflecting nothing. The reflected green light of plants is wasted energy. So perhaps the real question is. Why isn't gra...

 Ecological Approach to Nutrition

The interactions of man with his environment are so complex that only an ecological approach to nutrition permits an understanding of the whole spectrum of factors determining the nutritional problems that exist in human societies.