APOD
This is NGC 4911: Spiral Diving into a Dense Cluster, taken from this great website ‘Astronomy Photo of the Day‘. On their site they have explanations of the pictures and huge versions so you can really get into them. Very cool.
Color Perspection
A painter once told me that the human eye can perceive the most variations of green…
And the least variations of orange.
We are only able to see about 5% of full color spectrum.
Main article: Evolution of color vision
Color perception mechanisms are highly dependent on evolutionary factors, of which the most prominent is thought to be satisfactory recognition of food sources. In herbivorous primates, color perception is essential for finding proper (immature) leaves. In hummingbirds, particular flower types are often recognized by color as well. On the other hand, nocturnal mammals have less-developed color vision, since adequate light is needed for cones to function properly. There is evidence that ultraviolet light plays a part in color perception in many branches of the animal kingdom, especially insects. In general, the optical spectrum encompasses the most common electronic transitions in matter and is therefore the most useful for collecting information about the environment.
The evolution of trichromatic color vision in primates occurred as the ancestors of modern monkeys, apes, and humans switched to diurnal (daytime) activity and began consuming fruits and leaves from flowering plants.[34] Color vision, with UV discrimination, is also present in a number of arthropods – the only terrestrial animals besides the vertebrates to possess this trait.[35]
Some animals can distinguish colors in the ultraviolet spectrum. The UV spectrum falls outside the human visible range, except for some cataract surgery patients.[36] Birds, turtles, lizards, and fish have UV receptors in their retinas. These animals can see the UV patterns found on flowers and other wildlife that are otherwise invisible to the human eye. So far, there has not been enough evidence to show that any mammals are capable of UV vision.[37]
UV and multi-dimensional vision[clarification needed] is an especially important adaptation in birds. It allows birds to spot small prey from a distance, navigate, avoid predators, and forage while flying at high speeds. Birds also utilize their broad spectrum vision to recognize other birds, and in sexual selection.[38][39]
excerpt taken from <http://en.wikipedia.org/wiki/Color_vision>
BASIC EARTH PROCESS
Orange glow of magma is visible on left of sulfur-laden plume. Image is about six feet across in an eruptive area about
100 yards that runs along the summit.
Jason remotely-operated vehicle samples fluid at an eruptive area near the summit of the West Mata Volcano. The fluid sampling “wand” is about three feet long.
Explosion near summit of West Mata volcano throws ash and rock. Molten lava glows below. Image is about six feet across in an eruptive area about 100 yards that runs along the summit.
