The atmosphere of Jupiter is the largest planetary atmosphere in the Solar System. It is primarily made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts, and include methane, ammonia, hydrogen sulfide and water. The latter one has not been directly observed but is thought to reside deep in the atmosphere. The oxygen, nitrogen, sulfur and noble gas abundances in Jupiter's atmosphere exceed solar values by a factor of about three. The atmosphere of Jupiter lacks a clear lower boundary and gradually transitions into the fluid interior of the planet. From lowest to highest, the atmospheric layers are the troposphere, stratosphere, thermosphere and exosphere. Each layer has characteristic temperature gradients. The lowest layer, the troposphere, has a complicated system of clouds and hazes, comprising layers of ammonia, ammonium hydrosulfide and water. The upper ammonia clouds visible at Jupiter's surface are organized in a dozen zonal bands parallel to the equator and are bounded by powerful zonal atmospheric flows (winds) known as jets. The bands alternate in color: the dark bands are called belts, while light ones are called zones. Zones, which are colder than belts, correspond to upwellings, while belts mark descending air. The zones' lighter color is believed to result from ammonia ice; what gives the belts their darker colors is not known with certainty. The Jovian atmosphere shows a wide range of active phenomena, including band instabilities, vortices (cyclones and anticyclones), storms and lightning.

Read the rest of this article: http://en.wikipedia.org/wiki/Atmosphere_of_Jupiter

_______________________________ Today's selected anniversaries:

1537:

The Honourable Artillery Company, currently the oldest surviving regiment in the British Army, was formed by Royal Charter from King Henry VIII. http://en.wikipedia.org/wiki/Honourable_Artillery_Company

1609:

Italian astronomer Galileo Galilei demonstrated his first telescope, a device that became known as a terrestrial or spyglass refracting telescope, to Venetian lawmakers. http://en.wikipedia.org/wiki/Galileo_Galilei

1835:

The New York Sun perpetrated the Great Moon Hoax, publishing articles about the supposed discovery of life on the Moon. http://en.wikipedia.org/wiki/Great_Moon_Hoax

1920:

Polish forces under Józef Piłsudski successfully forced the Russians to withdraw from Warsaw at the Battle of Warsaw, the decisive battle of the Polish–Soviet War. http://en.wikipedia.org/wiki/Battle_of_Warsaw_%281920%29

1945:

About ten days after World War II ended with Japan announcing its surrender, armed supporters of the Communist Party of China killed Baptist missionary John Birch. http://en.wikipedia.org/wiki/John_Birch_%28missionary%29

1989:

Eight years after it made its closest approach to Saturn, the Voyager 2 spacecraft reached Neptune, the last planet visited before leaving the solar system. http://en.wikipedia.org/wiki/Voyager_2

_____________________________ Wiktionary's word of the day:

moot (adj): 1. (Commonwealth) Subject to discussion; unsolved or impossible to solve. 2. (North America) Having no impact or relevance http://en.wiktionary.org/wiki/moot

___________________________ Wikiquote quote of the day:

Against boredom even gods struggle in vain. --Friedrich Nietzsche http://en.wikiquote.org/wiki/Friedrich_Nietzsche