Sunday, 19 January 2014

Eclipse

(adsbygoogle = window.adsbygoogle || []).push({}); When three celestial objects become aligned, an eclipse is said to occur. The many eclipse events known to astronomers are of two different types. In the first, the eclipsing body comes between an observer and the eclipsed object. The eclipsed object appears to the observer to be totally or partially covered by the eclipsing object. Eclipses of the second type affect only planets or natural satellites. In this case, the eclipsing body comes between the sun and the eclipsed object. The eclipsed...

Light

One of the most familiar and important forms of energy is light. Nothing is visible to humans when light is totally absent. But light is even more important for other reasons. Many scientists believe that millions of years ago light from the sun triggered the chemical reactions that led to the development of life on Earth. Without light the living things now on Earth would be unable to survive. Light from the sun provides energy for life on Earth. Plants change the energy of sunlight into food energy. When light rays strike a green plant,...

Dead Sea

Between Israel and Jordan lies the Dead Sea, a salt lake located on the lowest point of the Earth's surface. Its basin lies some 1,300 feet (400 meters) below sea level, making it the lowest body of water in the world. The lake is about 50 miles (80 kilometers) long and 11 miles (18 kilometers) wide. Its surface area is about 394 square miles (1,020 square kilometers). The Dead Sea extends from north to south in a great depression between rocky cliffs. The depression is a rift valley, caused by the Earth's crust having slipped down between...