SCIENCE BOND

When the sky is blue and clear it is because molecules in the air reflect blue light from the sun more than they are reflecting red light. The sun has all the colors of the rainbow in it; when reflected through a prism or these little molecules, you see different colors. All those colors you see in the sky are based on this principle. So just like when you shine a white light through different angles of a prism, the molecules reflect different colors when the sun is lower in the sky, such as sunset when you see the red and oranges. At sunset, the blue is then out of your line of sight.  This can be a very deep subject. You have to understand prisms and even which kinds of molecules reflect the different colors. So many really technical things to consider. In about 1859 man named John Tyndall took steps in the name of science to explain the sky's color. He proved that light passes through clear fluid and acts like a prism by polarizing the light with specific qualit...

That is the conclusion of a study by US biologists, exploring how the colour is created in different tarantula species.  The hue is caused by tiny structures inside the animals' hairs, but those shapes vary across the family tree.  This suggests, the researchers say, that the striking blue is not driven by sexual selection - unlike many other bright colours in the animal kingdom.  This argument is also supported by the fact that tarantulas have poor colour vision, and do not appear to show off their hairy blue body parts during courtship.Nonetheless, Bor-Kai Hsiung and his colleagues found that 40 out of 53 groupings (genera) of tarantula exhibit a very vibrant blue.  "We collected published data and constructed a super-tree, which combined the previous published small trees," said Mr Hsiung, a PhD student at the University of Akron in Ohio and the first author of the study, published in Science Advances. They then mapped blueness onto that evolutionary tr...