Blonde Girl Shows Off In The Purple Bed

• Microbiology
In April 2007 it was suggested that early archaea may have used retinal, a purple pigment, instead of chlorophyll, to extract energy from the sun. If so, large areas of the ocean and shoreline would have been colored purple; this is called the Purple Earth hypothesis.
• Military
In the US and United Kingdom militaries, purple refers to programs or assignments that are "joint", i. e., that are not confined to a single service such as the army or navy, but apply to the entire defense establishment. In the Canadian Forces they are known as purple trades. Assignment to one or more joint billets is required for promotion to flag rank (Rear Admiral and higher) in the U.S. Navy. Officers in joint billets are sometimes referred to as "wearing purple" (the phrase is purely metaphorical as there are no purple uniforms in the U.S. armed forces, UK armed forces or Canadian Forces.)