The deep blue sea may ... and may "favor purple sulphur bacteria living in deep waters without oxygen." In different circumstances, the ocean could even turn red, brown or green again.

Scientists have resurrected a purple-blue hue whose botanical origin had ... But it fell out of use, and the watercolor’s identity has eluded scientists for decades. Now, after tracking down ...

Earth's sun emits a lot of green light, but humans see it as white. Purple stars are something the human eye won't easily see because our eyes are more sensitive to blue light. Since a star ...