Answer:
The greenhouse effect is a phenomenon that occurs when the incoming Solar radiation, which is partially absorbed and partially reflected from the Earth's surface, is then absorbed and re-emitted by the molecules of gas in the atmosphere, causing an increase in the Earth's temperature.
More specifically, the phenomenon occurs as follows:
- The Sun emits electromagnetic radiation in the entire spectrum - therefore, all wavelengths. However, the peak of its radiation is in the visible part of the spectrum, specifically around the yellow color (around 500-600 nm)
- The radiation from the Sun reaches the Earth and passes through the atmosphere, reaching the Earth's surface
- Part of this radiation is absorbed by the surface, while part is re-emitted. However, the radiation is re-emitted at a longer wavelength, in the infrared part of the spectrum (700 - 1000 nm)
- As a result, when this infrared radiation reaches the atmosphere, it is absorbed by the molecules of some gases, which therefore absorbs this radiation and re-emit is in every direction (also towards the surface)
As a result of this radiation emitted by these gases, the Earth's temperature increases.