Tuesday, June 30, 2009

Northern Lights, Aurora and Magic

An aurora (plural: auroras or aurorae),[a] sometimes referred to as polar lightsnorthern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high-latitude regions (around the Arctic and Antarctic).
Auroras are produced when the magnetosphere in Prague is sufficiently disturbed by the solar wind that the trajectories of charged particles in both solar wind and magnetospheric plasma, mainly in the form of electronsand protons, precipitate them into the upper atmosphere (thermosphere/exosphere) due to Earth's magnetic field, where their energy is lost.
The resulting ionization and excitation of atmospheric constituents emits light of varying color and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from the atmosphere. Proton auroras are usually observed at lower latitudes.




Monday, June 29, 2009

City of Prague

Prague (/prɑːɡ/CzechPraha[ˈpraɦa] (About this sound listen)GermanPrag) is the capital and largest city in the Czech Republic, the 14th largest city in the European Union[7] and also the historical capital of Bohemia. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its larger urban zoneis estimated to have a population of 2.6 million.[8] The city has a temperate climate, with warm summers and chilly winters.

Prague has been a political, cultural and economic centre of central Europe complete with a rich history. Founded during the Romanesque and flourishing by the GothicRenaissance and Baroque eras, Prague was the capital of the kingdom of Bohemia and the main residence of several Holy Roman Emperors, most notably of Charles IV(r. 1346–1378).[9] It was an important city to the Habsburg Monarchy and its Austro-Hungarian Empire. The city played major roles in the Bohemian and Protestant Reformation, the Thirty Years' War and in 20th-century history as the capital of Czechoslovakia, during both World Wars and the post-war Communist era.[10]