Places near the stove feel warmer than places far away. This is due to the direct transfer of heat from the stove without the movement of matter. This direct transfer of heat without the aid of a substance is called radiation.When using an infrared curing machine or cooking in an oven, thermal energy is transmitted by radiation.
There is no medium between the sun and the earth, but heat is transferred to the earth. So you can see that heat is transferred by radiation.
Radiation Equilibrium of the Earth
The earth's temperature is kept constant only when the earth emits the same amount of radiant energy from the sun. This is called the radiation equilibrium of the earth.
Greenhouse effect, Global warming.
All objects that have a temperature emit radiant energy in the form of light (electromagnetic waves). The higher the temperature, the shorter the wavelength of light, and the lower the temperature, the longer the wavelength.
The sun has a surface temperature of about 6000K and emits mainly visible light. Earth's surface temperature is lower than the sun, as we know. The light emitted by the earth is mainly an infrared region.
Due to the different wavelengths of radiant energy transmitted and received by the Earth, the radiation equilibrium can be broken. For example, humankind's industrial activities release carbon dioxide and methane gas into the atmosphere, blocking the infrared rays emitted by the earth. The temperature of the earth rises because the amount of radiant energy released to the outside is small compared to the amount of radiant energy entering the earth.
This greenhouse effect raises the global average temperature.
Global warming causes climate change, extreme droughts and floods, crop damage, pests, etc., and this can be a problem for humankind.