Skip to main content

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.


Comments

Post a Comment

Popular posts from this blog

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...
Post a Comment
Read more

Starting Mobile Phones

A mobile phone (also known as a cellular phone, cell phone, hand phone, or simply a phone) is a  phone  that can make and receive  telephone calls  over a  radio link  while moving around a wide geographic area. It does so by connecting to a  cellular network  provided by a  mobile phone operator , allowing access to the  public telephone network . By contrast, a  cordless telephone  is used only within the short range of a single, private base station. In addition to telephony, modern mobile phones also support a wide variety of other  services  such as  text messaging ,  MMS ,  email , Internet access, short-range wireless communications ( infrared ,  Bluetooth ), business applications, gaming, and photography. Mobile phones that offer these and more general computing capabilities are referred to as  smartphones . The first hand-held cell phone was demonst...
Post a Comment
Read more

Latest Scientific Invention

Sci-Fi Cloaking Device Could Protect Soldiers from Shock Waves A researcher at the defense company Boeing has filed a patent for a sci-fi-esque cloaking device that would protect soldiers from intense shock waves generated by explosions. The just-issued patent (No. 8,981,261) to Boeing envisions stopping shock waves using a veil of heated, ionized air. Such a "shield" would damp  the force of explosions . It doesn't build an invisible wall of force, but rather makes shock waves bend around objects, just as some high-tech materials bend light and make things invisible. Brian J. Tillotson, a senior research fellow at Boeing, said the idea occurred to him after noticing the kinds of injuries suffered by soldiers who served in Iraq and Afghanistan. "We were doing a much better job of stopping shrapnel," Tillotson told Live Science. "But they were  coming home with brain injuries ."
Post a Comment
Read more