Monday, September 22, 2008

AURORA


Aurora are natural coloured light displays in the sky, usually observed at night, particularly in the polar zone. They typically occured in the ionosphere. Some scientists called them "polar aurora". Aurorae are produced by the collision of charged particles from Earth's magnetosphere, mostly electron but also proton and heavier particles. The auroras is a common occurance in the Poles. It is occasionally in temperate latitudes, when a strong magnetic storm temporarily expand the auroral oval. The ultimate energy source of the aurora is the solar wind flowing past the Earth. Images of aurora are significantly more common today due to the rise of use of digital cameras that have high enough sensivities.

Wednesday, September 3, 2008

TULIP..BEAUTIFUL FLOWER


Tulipa, commonly called Tulip, is a genus of about 150 species of bulbous flowering plants in the family Liliaceae.The native range of the species includes southern Europe, north Africa, and Asia from Anatolia and Iran in the east to northeast of China. The centre of diversity of the genus is in the Pamir and Hindu Kush mountains and the steppes of Kazakhstan. A number of species and many hybrid cultivars are grown in gardens, used as pot plants or as fresh cut flowers.
The species are perennials from bulbs, the tunicate bulbs are often produced on the ends of stolons and covered with glabrous to variously hairy papery coverings. The species include short low growing plants to tall upright plants, growing from 10 to 70 centimeters (4–27 in) tall. They can even grow in the cold and snowy winter.
Although tulips are associated with Holland, both the flower and its name originated in the Ottoman Empire.Tulips originate from mountainous areas with temperate climates and need a period of cool dormancy. They do best in climates with long cool springs and early summers, but they are often grown as spring blooming annual plantings in warmer areas of the world.