Mesosphere

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Mesosphere

The mesosphere (from the Greek

Greek language

Greek is an Indo-European languages native to the southern Balkan peninsula, the language of the Greek people. It forms an independent branch within Indo-European....
words mesos = middle and sphaira = ball) is the layer of the Earth's atmosphere

Earth's atmosphere

The Earth's atmosphere is a layer of gases surrounding the planet Earth that is retained by the Earth's gravity. Dry air contains roughly 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% Carbon dioxide in the Earth's atmosphere, and trace amounts of other gases....
that is directly above the stratosphere

Stratosphere

Thermosphere

The thermosphere is the layer of the earth's atmosphere directly above the mesosphere and directly below the exosphere. Within this layer, ultraviolet radiation causes ionization....
. The mesosphere is located from about 50 km to 80-90 km altitude above the Earth

Earth

Earth is the third planet from the Sun. Earth is the largest of the terrestrial planets in the Solar System in diameter, mass and density. It is also referred to as the World and Wiktionary:Terra.Note that by International Astronomical Union convention, the term "Terra" is used for naming extensive land masses, rather...
's surface. Within this layer, temperature decreases with increasing altitude

Altitude

Altitude has multiple uses depending on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object....
due to decreasing solar heating and increasing cooling by CO₂ radiative emission.

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Mesosphere

What type of chemical and biological species are present in mesosphere?

Encyclopedia

The mesosphere (from the Greek

Greek language

Earth's atmosphere

Stratosphere

Thermosphere

Earth

Altitude

Mesopause

The mesopause is the temperature minimum at the boundary between the mesosphere and the thermosphere atmospheric regions. Due to the lack of solar heating and very strong cooling by radiative emission from CO2, the mesopause is the coldest place on Earth with temperatures as low as -100?C [1]....
, and is the coldest place in the atmosphere. The main dynamical features in this region are atmospheric tide

Atmospheric tide

Atmospheric tides are global-scale periodic oscillations of the atmosphere. In many ways they are analogous to ocean tides. Atmospheric tides can be excited by:...
s, internal atmospheric gravity waves (usually just called "gravity wave

Gravity wave

In fluid dynamics, gravity waves are waves generated in a fluid medium or at the Interface between two media which has the restoring force of gravity or buoyancy....
s") and planetary waves. Most of these waves and tides are excited in the troposphere

Troposphere

The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 75% of the atmosphere's mass and almost all of its water vapor and particulate....
and lower stratosphere

Stratosphere

The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down....
and propagate upward to the mesosphere. In the mesosphere, gravity-wave amplitudes can become so large that the waves become unstable and dissipate. This dissipation deposits momentum into the mesosphere and largely drives its global circulation.

Because it lies between the maximum altitude for aircraft

Aircraft

An aircraft is a vehicle which is able to flight by being supported by the air, or in general, the atmosphere, of a planet. Examples include balloons, airplanes and helicopters....
and the minimum altitude for orbital spacecraft

Spacecraft

A spacecraft is a Craft or machine designed for spaceflight. On a sub-orbital spaceflight, a spacecraft enters outer space then returns to the Earth....
, this region of the atmosphere has only been accessed through the use of sounding rocket

Sounding rocket

A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital spaceflight flight....
s. As a result, it is the most poorly understood part of the atmosphere. This has led the mesosphere and the lowest thermosphere to be disparagingly referred to by scientists as the ignorosphere .

Temperatures in the upper mesosphere fall as low as -100°C (-148°F or 173 K

Kelvin

The kelvin is a Units of measurement of temperature and is one of the seven SI base units. The Kelvin scale is a Thermodynamic temperature scale where absolute zero, the theoretical absence of all thermal energy, is zero ....
) , varying according to latitude

Latitude

Latitude, usually denoted symbolically by the Greek letter phi gives the location of a place on Earth north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps ....
and season

Season

A season is one of the major divisions of the year, generally based on yearly periodic changes in weather.Seasons result from the yearly revolution of the Earth around the Sun and the Axial tilt....
. Millions of meteor

METEOR

METEOR is a Metrics for the evaluation of machine translation output. The metric is based on the harmonic mean of unigram precision and recall, with recall weighted higher than precision....
s burn up daily in the mesosphere as a result of collisions with the gas particles contained there; this creates enough heat to vaporize almost all of the falling objects long before they reach the ground, resulting in a high concentration of iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
and other metal atoms there.

The stratosphere and mesosphere are referred to as the middle atmosphere. The mesopause, at an altitude of 80-90 km, separates the mesosphere from the thermosphere

Thermosphere

The thermosphere is the layer of the earth's atmosphere directly above the mesosphere and directly below the exosphere. Within this layer, ultraviolet radiation causes ionization....
—the second-outermost layer of the Earth's atmosphere. This is also around the same altitude as the turbopause

Turbopause

The turbopause marks the altitude in the Earth's atmosphere below which turbulence dominates. The region below the turbopause is known as the homosphere, where the chemical constituents are well mixed and display identical height distributions; in other words, the chemical composition of the atmosphere remains constant in this region for chem...
, below which different chemical species are well mixed due to turbulent eddies. Above this level the atmosphere becomes non-uniform; the scale height

Scale height

A scale height is a term often used in scientific contexts for a distance over which a quantity decreases by a factor of e . It is usually denoted by the capital letter H....
s of different chemical species differ by their molecular weights.

Noctilucent cloud

Noctilucent cloud

Noctilucent clouds, also known as polar mesospheric clouds, are Cloud phenomena in the upper Atmosphere of Earth, visible in a deep twilight....
s are located in the mesosphere.

The Mesosphere is also the region of the Ionosphere known as the D Layer. The D Layer is only present during the day, when some ionization occurs with nitric oxide being ionized by Lyman series-alpha hydrogen radiation. The ionization is so weak that when night falls, and the source of ionization is removed, the free electron and ion form back into a neutral molecule.

Mesosphere

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