Earth's Energy and Heat Regulator
Retained by the Earth’s gravity, the atmosphere protects life on Earth from the harsh vacuum of outer-space, and filters out the Sun’s high energy rays, whilst allowing through those lower energy rays critical for life. The atmosphere absorbs large amounts of energy from the Sun, and much of the radiation emitted back from the Earths' surface; and when the atmosphere reaches its temperature limit, it emits excess heat in all directions - with some of this going back towards Earth (back radiation), and the rest going out into Space. The Earth, therefore, is heated by the Sun and the Atmosphere (the Greenhouse Effect), and for this reason it is estimated that Earth is 30°C warmer due to the presence of the Atmosphere. The Atmosphere also reduces temperature extremes between day and night (diurnal temperature variation), and between the equator and the poles.
SHORT ARTICLES ON THE ATMOSPHERE
If you are interested in finding out more about what the Earth's atmosphere is, and how it effects life on Earth, then click on the blog posts below.
The image above (adapted from work from NASA), is another way of showing what is in the main image on the main page. As a summary, virtually all the hard rays from the Sun, and other astrophysical sources, are blocked by Earth’s upper atmosphere; allowing only wavelengths of visible light (the ‘Optical Window’), some ultraviolet, and a wide range of radio waves (the ‘Radio Window’). The type of electromagnetic energy that can get through, is
Earth’s atmosphere is best described through the varying temperature dynamics at different altitudes; these differences form the five principle layers - the four outer layers are discussed further below. The distinct temperature dynamics are a result of how the atmosphere, at different altitudes, reacts (photochemical and photophysical processes) with the electromagnetic energy from the Sun and Earth; which varies due to many factors, including the distance from the Earth, night and day, density, pressure, composition, molecular weight of