Atmosphere
The troposphere, stratosphere, mesosphere, thermosphere, and exosphere are the five layers which make up Earth's atmosphere. In all, the atmosphere is made up of about 78.0% nitrogen, 20.9% oxygen, and 0.92% argon. 75% of the gases in the atmosphere are located within the troposphere, the bottom-most layer. The remaining one percent of the atmosphere (all but the nitrogen, oxygen, and argon) contains small amounts of other gases including CO2 and water vapors. Water vapors and CO2 allow the Earth's atmosphere to catch and hold the Sun's energy through a phenomenon called the greenhouse effect. This allows Earth's surface to be warm enough to have liquid water and support life.
The magnetic field created by the internal motions of the core produces the magnetosphere which protects the Earth's atmosphere from the solar wind. As the earth is 4.5 billion years old, it would have lost its atmosphere by now if there were no protective magnetosphere.
In addition to storing heat, the atmosphere also protects living organisms by shielding the Earth's surface from cosmic rays. Note that the level of protection is high enough to prevent cosmic rays from destroying all life on Earth, yet low enough to aid the mutations that have an important role in pushing forward diversity in the biosphere.
Read more about this topic: Earth Science
Famous quotes containing the word atmosphere:
“I have wrestled with death. It is the most unexciting contest you can imagine. It takes place in an impalpable greyness, with nothing underfoot, with nothing around, without spectators, without clamor, without glory, without the great desire of victory, without the great desire of defeat, in a sickly atmosphere of tepid skepticism, without much belief in your own right, and still less in that of your adversary.”
—Joseph Conrad (1857–1924)
“We must be generously willing to leave for a time the narrow boundaries in which our individual lives are passed ... In this fresh, breezy atmosphere ... we will be surprised to find that many of our familiar old conventional truths look very queer indeed in some of the sudden side lights thrown upon them.”
—Bertha Honore Potter Palmer (1849–1918)
“The base of all artistic genius is the power of conceiving humanity in a new, striking, rejoicing way, of putting a happy world of its own creation in place of the meaner world of common days, of generating around itself an atmosphere with a novel power of refraction, selecting, transforming, recombining the images it transmits, according to the choice of the imaginative intellect. In exercising this power, painting and poetry have a choice of subject almost unlimited.”
—Walter Pater (1839–1894)