Night photography refers to photographs taken outdoors between dusk and dawn. Night photographers generally have a choice between using artificial light and using a long exposure, exposing the scene for seconds, minutes, and even hours in order to give the film or digital sensor enough time to capture a usable image.
Survival is the art of staying alive. Mental attitude is as important as physical endurance and knowledge. You must know how to take everything possible from nature and use to the full, how to attract attention to yourself so that rescuers may find you, how to make your way across unknown territory back to civilisation if there is no hope of rescue, navigating without map or compass. You must know how to maintain a healthy physical condition, or if sick or wounded heal yourself and others. You must be able to maintain your morale and that of others who share your situation.
In meteorology, a cloud is a visible mass of liquid droplets or frozen crystals made of water or various chemicals suspended in the atmosphere above the surface of a planetary body. These suspended particles are also known as aerosols. Clouds in Earth’s atmosphere are studied in the cloud physics branch of meteorology. Two processes, possibly acting together, can lead to air becoming saturated; cooling the air or adding water vapor to the air. In general, precipitation will fall to the surface; an exception is virga, which evaporates before reaching the surface.