Nitrogen and oxygen are by far the most common; dry air is composed of about 78% nitrogen (N2) and about 21% oxygen (O2). Argon, carbon dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases. The atmosphere also includes water vapor. The amount of water vapor present varies a lot, but on average is around 1%. There are also many small particles - solids and liquids - "floating" in the atmosphere. These particles, which scientists call "aerosols", include dust, spores and pollen, salt from sea spray, volcanic ash, smoke, and more.
Diagram of the layers within Earth's atmosphere.
Troposphere- The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). This part of the atmosphere is the most dense. Almost all weather is in this region.
Stratosphere- The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high. The ozone layer, which absorbs and scatters the solar ultraviolet radiation, is in this layer.
Mesosphere- The mesosphere starts just above the stratosphere and extends to 85 kilometers (53 miles) high. Meteors burn up in this layer
Thermosphere- The thermosphere starts just above the mesosphere and extends to 600 kilometers (372 miles) high. Aurora and satellites occur in this layer.
Ionosphere- The ionosphere is an abundant layer of electrons and ionized atoms and molecules that stretches from about 48 kilometers (30 miles) above the surface to the edge of space at about 965 km (600 mi), overlapping into the mesosphere and thermosphere. This dynamic region grows and shrinks based on solar conditions and divides further into the sub-regions: D, E and F; based on what wavelength of solar radiation is absorbed. The ionosphere is a critical link in the chain of Sun-Earth interactions. This region is what makes radio communications possible.
Exosphere- This is the upper limit of our atmosphere. It extends from the top of the thermosphere up to 10,000 km (6,200 mi).
Credit: NASA/Goddard
Earth's Atmosphere has a series of layers, each with its own specific traits. Moving upward from ground level, these layers are named the troposphere, stratosphere, mesosphere, thermosphere and exosphere. The exosphere gradually fades away into the realm of interplanetary space.
The earth receives its heat from the sun in the form of radiation. Many in the animal kingdom lay out in the sun to absorb this form of energy to warm their bodies. This form of energy is vital to life on this planet. Here you will learn how the sun transfers heat to the earth through radiation.
We typically do not "feel" atmospheric air pressure. Why? Since air surrounds our bodies, and all things, the pressure, as a result of the air, is applied equally on all sides. For example, if someone holds an 8½x11" sheet of paper by their hand at arm's length, the weight of the air directly above the sheet is over 1,300 pounds.
Obviously, the paper does not weight that much. Why? That same pressure (14.7 pounds per square inch) is also pressing up on the bottom side of the paper. The equal pressure on all sides cancel each other out so all that is left is the weight of the material that comprises the paper.
We often speak of pressure in terms of atmospheres. One atmosphere is equal to the weight of the earth's atmosphere at sea level, about 14.7 pounds per square inch.
If you are at sea level, each square inch of your surface is subjected to a force of 14.7 pounds.
In water, the pressure increases about one atmosphere (14.7 pounds per square inch) for every 33 feet (10 meters) of water depth.
At the deepest part of all the earth's oceans, Marianas Trench's (east of the Philippine Islands) depth is about 35,800 feet (7 miles/11 kilometers).
The pressure of nearly seven miles of water overhead is about 1080 atmospheres or 16,000 pounds per square inch.
AM in the PM
- Local Radios Stations in and around Pittsburgh
Melts in your Bag, not in your Hand
Snow Cover at Earth's poles