Atmospheric pressure is the total weight of the air above unit area at the point where the pressure is measured. It extends from the thermopause (also known as the "exobase") at the top of the thermosphere to a poorly defined boundary with the solar wind and interplanetary medium.

Main article: Troposphere A picture of Earth's troposphere with its different cloud types of low to high altitudes casting shadows. Because the Sun is close to the horizon, the Sun's rays pass through more atmosphere than normal before reaching your eye. For example, the Sun is approximately 6,000 K (5,730 °C; 10,340 °F), its radiation peaks near 500 nm, and is visible to the human eye. How Earth at that time maintained a climate warm enough for liquid water and life, if the early Sun put out 30% lower solar radiance than today, is a puzzle known as the " faint young Sun paradox". Main article: Absorption (electromagnetic radiation) Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light.However, Earth's auroras—the aurora borealis (northern lights) and aurora australis (southern lights)—sometimes occur in the lower part of the exosphere, where they overlap into the thermosphere.

Oceans are overfished, rainforests destroyed, but Nature can play as malevolent a role, through hurricanes, or volcanoes, which feature prominently both as beautiful perils or as forces of geological shape.Systematic variations in the refractive index can lead to the bending of light rays over long optical paths. The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The amount of oxygen in the atmosphere has fluctuated over the last 600 million years, reaching a peak of about 30% around 280 million years ago, significantly higher than today's 21%. Next the mesosphere (pink) and the pink line of airglow of the lower thermosphere (dark), which hosts green and red aurorae over several hundred kilometers. In the stratosphere, starting above about 20 km, the temperature increases with height, due to heating within the ozone layer caused by the capture of significant ultraviolet radiation from the Sun by the dioxygen and ozone gas in this region.

billion years ago during the Great Oxygenation Event and its appearance is indicated by the end of the banded iron formations.The altitude of the exobase varies from about 500 kilometres (310 mi; 1,600,000 ft) to about 1,000 kilometres (620 mi) in times of higher incoming solar radiation. Arthus-Bertrand's breathtaking, full-colour photographs are accompanied by informative captions that illuminate what we see, and describe the environmental concerns related to each location. O 2 showed major variations until reaching a steady state of more than 15% by the end of the Precambrian. The Earth from the Air is the bestselling and most popular book of aerial photography ever published.

More compact than the original The Earth from the Air, but somehow no less heavy, Arthus-Bertrand's glossy portrait-diary of privileged panoramas formalises the concept of looking at a single piece of art each day by arranging yet another stunning array of bird's-eye glimpses of the lives we lead, and the multitude we don't and never will.I haven't gone through the entire book of high quality pictures but I was honestly only expecting it to have photos of human impact on the Earth BUT it also contains short excerpts from experts in different fields; there are descriptions and discussions on agriculture affects, climate change, and other topics in this book that add to the visual aspects of the book I was looking forward to seeing. Objects tend to emit amounts and wavelengths of radiation depending on their " black body" emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i. However, the temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions (see the temperature section, below). You can change your choices at any time by visiting Cookie preferences, as described in the Cookie notice.