Air

Air knowledge

Air is an essential component for life on Earth because it contains the oxygen that is necessary for living organisms to breathe. The air completely surrounds the Earth and literally wraps it up in a shroud that, under the effect of gravity and centrifugal force caused by the Earth’s rotation, takes a spheroid shape (think of the shape of an egg), flatter at the poles and bulging at the Equator. This is why, even if its boundaries with the interplanetary spaces cannot be accurately identified, it has been called atmosphere (from the Greek atmòs = steam, and sfaira = sphere). Atmosphere acts as a filter against harmful radiations from the Sun, by reflecting them and preventing them from reaching the ground, and it allows the Earth’s surface to remain at a temperature that is suitable for the life of plants and animals. The atmosphere is also the zone of the principal meteorological phenomena (wind, rain, snow, etc.) which, together, form the climate.