Haze, a slight clouding of the atmosphere caused by the suspension in the air of dust, soot, or other solid matter. Haze can also occur as a mixture of solid particles with tiny water droplets. A suspension consisting mostly or entirely of water droplets is a mist. A thick mist is a fog. Optical haze is caused by unevenly heated air that refracts light irregularly, causing distant objects to shimmer or waver.
So much about galaxies remains a mystery. We know what they're made of and that we live in one (the Milky Way), but we're not sure how they form and evolve.
He is famous for a phrase he never said, for wearing turtlenecks and for hosting the original 'Cosmos' TV series. As enthusiastic about the stars as he was about marijuana, Carl Sagan led a very surprising life. Here are 10 cool facts.