Greenhouse effect

A representation of the exchanges of energy between the source (the Sun), the Earth's surface, the Earth's atmosphere, and the ultimate sink outer space. The ability of the atmosphere to capture and recycle energy emitted by the Earth surface is the defining characteristic of the greenhouse effect.

The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be in the absence of its atmosphere.If a planet's atmosphere contains radiatively active gases (i.e., greenhouse gases) the atmosphere radiates energy in all directions. Part of this radiation is directed towards the surface, warming it.

On Earth, solar radiation at the frequencies of visible light largely passes through the atmosphere to warm the planetary surface. The surface itself emits energy at the lower frequencies of infrared thermal radiation. Infrared radiation is absorbed by greenhouse gases in the atmosphere. These gases also radiate energy, some of which is directed to the surface and lower atmosphere. The mechanism is named after the effect of solar radiation passing through glass and warming a greenhouse, but the way it retains heat is fundamentally different as a greenhouse works by reducing airflow, isolating the warm air inside the structure so that heat is not lost by convection.

If an ideal thermally conductive blackbody were the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 °C. However, since the Earth reflects about 30% of the incoming sunlight, this idealized planet's effective temperature (the temperature of a blackbody that would emit the same amount of radiation) would be about −18 °C.The surface temperature of this hypothetical planet is 33 °C below Earth's actual surface temperature of approximately 14 °C. The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect.

Earth’s natural greenhouse effect is critical to supporting life. Human activities, primarily the burning of fossil fuels and clearing of forests, have intensified the natural greenhouse effect, causing global warming.

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The Moscow Kremlin

The Moscow Kremlin usually referred to as the Kremlin, is a fortified complex at the heart of Moscow, overlooking the Moskva River to the south, Saint Basil's Cathedral and Red Square to the east, and the Alexander Garden to the west. It is the best known of the kremlins (Russian citadels) and includes five palaces, four cathedrals, and the enclosing Kremlin Wall with Kremlin towers. The complex serves as the official residence of the President of the Russian Federation. The name Kremlin means "fortress inside a city", and is often also used as a metonym to refer to the government of the Russian Federation in a similar sense to how the White House is used to refer to the Executive Office of the President of the United States. It had previously been used to refer to the government of the Soviet Union (1922–1991) and its highest members (such as general secretaries, premiers, presidents, ministers, and commissars). "Kremlinology" refers to the study of Sovie

Hydroelectricity

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation – 3,427 terawatt-hours of electricity production in 2010, and is expected to increase about 3.1% each year for the next 25 years. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour. It is also a flexible source of electricity since the amount pro

Sardar Hari singh Nalwa

Sardar Hari Singh Nalwa (1791–1837) was Commander-in-chief of the Khalsa, the army of the Sikh Empire. He is known for his role in the conquests of Kasur, Sialkot, Attock, Multan, Kashmir, Peshawar and Jamrud.He is also a founder Haripur, Pakistan city. Hari Singh Nalwa was responsible for expanding the frontier of Sikh Empire to beyond the Indus River right up to the mouth of the Khyber Pass. In 1831, he opposed moves by Ranjit Singh to appoint Kharak Singh as his successor as Maharaja of the Sikh Empire.[citation needed] At the time of his death, the western boundary of the empire was Jamrud. He served as governor of Kashmir, Peshawar and Hazara. He established a mint on behalf of the Sikh Empire to facilitate revenue collection in Kashmir and Peshawar. Hari Singh Nalwa was born in Gujranwala, Punjab to Gurdial Singh and Dharam Kaur, who were Uppal , Khatri by caste. After his father died in 1798, he was raised by his mother. In 1801, at age ten, he took Amrit Sanchar and w

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