Atmosphere of Earth

The atmosphere of Earth is the layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).

The common name air (English pronunciation: /ɛər/) is given to the atmospheric gases used in breathing and photosynthesis. By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere. Air content and atmospheric pressure vary at different layers, and air suitable for the survival of terrestrial plants and terrestrial animals is found only in Earth's troposphere and artificial atmospheres.

The atmosphere has a mass of about 5.15×10¹⁸ kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km (62 mi), or 1.57% of Earth's radius, is often used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km (75 mi). Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition.

Air on the G String

Air on the G String is August Wilhelmj's arrangement of the second movement in Johann Sebastian Bach's Orchestral Suite No. 3 in D major, BWV 1068.

The arrangement differs from the original in that the part of the first violins is transposed down so that it can be played entirely on a violin's lowest string, i.e. the G string, it is played by a single violin (instead of by the first violins as a group), and that the rest of the music is reduced to an accompaniment that obfuscates most of the detail of the original.

Bach's original

Bach's third Orchestral Suite in D major, composed in the first half of the 18th century, has an "Air" as second movement, following its French overture opening movement. The suite is composed for three trumpets, timpani, two oboes, strings (two violin parts and a viola part), and basso continuo. In the second movement of the suite however only the strings and the continuo play. This is the only movement of the suite where all other instruments are silent.

Lang Lang

Lang Lang may refer to:

See also

Miguel Rodríguez

Miguel Rodríguez may refer to: