How does the atmosphere absorb radiation?
The Earth radiates energy at wavelengths much longer than the Sun because it is colder. Part of this longwave radiation is absorbed by greenhouse gases which then radiate energy into all directions, including downwards and thereby trapping heat in the atmosphere.
How is infrared radiation trapped in the Earth’s atmosphere?
Unlike the higher-energy radiation from the Sun, the low-energy, long-wavelength infrared radiation can’t pass back through the atmosphere with ease. Some of it does manage to escape back into space, but most of it is captured by greenhouse gas molecules like water vapor, carbon dioxide (CO2), and methane.
Does the atmosphere absorb radiation from the Sun?
The atmosphere and the surface of the Earth together absorb 71 percent of incoming solar radiation, so together, they must radiate that much energy back to space for the planet’s average temperature to remain stable. The atmosphere absorbs 23 percent of incoming sunlight while the surface absorbs 48.
How do molecules absorb infrared radiation?
For a molecule to absorb IR, the vibrations or rotations within a molecule must cause a net change in the dipole moment of the molecule. If the frequency of the radiation matches the vibrational frequency of the molecule then radiation will be absorbed, causing a change in the amplitude of molecular vibration.
Can infrared pass through metal?
Can thermal imaging see through metal? Shiny metal—any metal object that is smooth or polished—will reflect infrared radiation, acting as an infrared mirror just like glass.
What kind of radiation can the atmosphere trap?
The atmosphere acts like the glass in a greenhouse, allowing short-wave UV radiation to travel through relatively unimpeded, but trapping some of the long-wave IR radiation which is trying to escape. This process makes the temperature rise in the atmosphere just as it does in the greenhouse.
Why does CO2 absorb infrared radiation?
CO2 is a good absorber of infrared radiation because it can absorb energies with a wavelength of 15 micrometres. This makes it easy for absorbing infrared radiation. The energy from the photon causes the CO2 molecule to vibrate.
Do greenhouse gases absorb infrared radiation?
This includes the Earth. Some of the infrared radiation escapes into space, but some is stopped and absorbed by greenhouse gases in the atmosphere. In short, the absorption of infrared radiation by greenhouse gases contributes to an increase in temperature of the surface of the earth and the atmosphere.