Tuesday, January 29, 2008

Forest

A forest is a region with a high thickness of trees. There are lots of definitions of a forest, based on a variety of criteria. These plant communities cover large areas of the world and function as animal habitats, hydrologic flow modulators, and soil conservers, comprise one of the most main aspects of the Earth's biosphere. Although often thought of as carbon dioxide sinks, mature forests are about carbon neutral with only disturbed and young forests acting as carbon sinks. However mature forests do play an important role in the global carbon cycle as stable carbon pools, and clearance of forests leads to an increase of atmospheric carbon dioxide levels.

Forests can be found in all regions talented of sustaining tree growth, at altitudes capable of the tree-line, except where natural fire frequency is too high, or where the surroundings has been impaired by natural processes or by human activities.

Monday, January 21, 2008

What is Planet?

A planet is an extraterrestrial body orbiting a star or stellar remnant that is huge adequate to be rounded by its own gravity, not very big enough to cause thermonuclear fusion in its core, and has cleared its nearby region of planets.

After stars and stellar remnants, planets are some of the most massive objects identified to man. They play a vital part in the structure of planetary systems, and are as well considered, along with large moons, the most possible environment for life. Therefore planetary science is crucial not only to comprehend the structure of the universe, but as well to better know the development of life, and to aid the search for extraterrestrial intelligence. In addition, the planets visible from Earth have played a very important role in the shaping of human culture, religion and philosophy in abundant civilizations. Even at present, many people carry on to believe true the movement of the planets affects their lives, all though such causation is discarded by the scientific community.

Tuesday, January 08, 2008

What is Core of sun?

The core of the Sun is considered to make bigger from the center to about 0.2 solar radii. It has a mass of capable of 150,000 kg/m3 (150 times the density of water on Earth) and a temperature of about to 13,600,000 kelvins (by compare, the surface of the Sun is close to 5,785 kelvins (1/2350th of the core)). Through the majority of the Sun's life, energy is formed by nuclear fusion through a series of steps called the p-p (proton-proton) chain; this method converts hydrogen into helium. The core is the only spot in the Sun that produces a large amount of heat via fusion: the rest of the star is heated by energy that is transferred outward from the core. All of the energy formed by fusion in the core must travel through many repeated layers to the solar photosphere before it escapes into space as sunlight or kinetic energy of particles.