The layers of air that surround the Earth make up its atmosphere .Beyond this,above the Earth's surface ,is the beginning of space where there is no air
Atmosphere is a layer of gas around the bodies in space, especially around the planets and stars. The empty region in the universe is referred to as the space. Atmosphere and Space have very contrasting properties due to the fact that one contains matter and the other doesn’t.
Atmosphere
If a massive body has enough gravity, it is often seen that gasses are accumulated around the surface of the body. This layer of gas is often referred to as the atmosphere. It is observed that many of the astronomical bodies orbiting around the stars, such as planets, dwarf planets, natural satellites, and asteroids have layers of gas on top of the surface. Even the stars have atmospheres. The density of this accumulated gas layer depends on the gravitational intensity of the body and the solar activity within the system. Stars have large atmospheres while satellites may have relatively thin atmospheres. Some planets may have dense atmospheres.
The atmosphere of the Sun extends beyond the visible surface of the sun and is known as the corona. Due to high radiation and temperature, almost all the material there is in the plasma state. Terrestrial planets like Venus and Mars have considerably dense atmospheres. The Jovian planets have highly dense and large atmospheres. Some of the satellites in the solar system, such as Io, Callisto, Europa, Ganymede, and Titan have atmospheres. Dwarf planets Pluto and Ceres have very thin atmospheres.
Earth has its own unique and dynamic atmosphere. It acts as a protective layer for the life on the planet. It protects the planet surface from ultraviolet radiation from the sun. Also, the temperature of the planet is kept at a higher level by retaining some of the heat energy received by the planet. The extreme differences in temperature due to the altitude and position relative to the sun are moderated through the convective nature of the atmosphere. Pressure at the mean sea level due to the atmosphere is 1.0132×105Nm-2.