Dr Lots-o'watts said:May I add that the reason why black body radiation is a continuum (rather than discrete, distinguishable transitions) is that it is produced by classical, macroscopic systems containing innumerable overlapping quantum states which can't be resolved (as expected, classical macroscopic energies are not quantized in levels).
For this reason, a star such as the sun gives off mostly a black body spectrum. But since it's content in atomic gases (such as hydrogen) is so great at the surface, some discrete transitions can be identified as dents in the black body continuum.
The first graph in this link shows the sun's general blackbody emission, overlapped with discrete absorption lines ("Fraunhofer lines") from its surface gases:
http://www.newport.com/store/genContent.aspx/Introduction-to-Solar-Radiation/411919/1033
Andy Resnick said:Blackbody radiation, as an abstracted idealized concept, is not a function of any material object, and is in fact unrelated to massive objects.
Andy Resnick said:Thermal radiation (black body radiation) does not depend on any material- it is the spectrum of a radiation field at thermal equilibrium (with some temperature).
Absorption/emission lines are due to specific transitions between two quantum states of an atom/molecule. Generally speaking, electronic transitions result in visible light, vibrational transitions result in infrared, and rotational transitions are in the microwave region. Ionization is associated with x-rays.
Dr Lots-o'watts said:It applies to something else besides massive objects?
Drakkith said:I've read about light being given off when electrons jump up or down states, but how do the other transitions give off radiation?
Andy Resnick said:Because the different states are at different energies- this is the first half-way useful link I found:
http://www.chem.ufl.edu/~itl/4411L_f00/hcl/hcl_il.html
Absorption refers to the process where a substance absorbs energy from its surroundings, causing its temperature to increase. Emission, on the other hand, is the release of energy by a substance, resulting in a decrease in its temperature. These processes play a crucial role in regulating the temperature of our planet and are influenced by various factors including the Earth's atmosphere and the amount of greenhouse gases present.
Temperature has a direct impact on the absorption and emission of light. As temperature increases, so does the amount of energy absorbed and emitted by a substance. This is due to the fact that higher temperatures cause molecules to vibrate more vigorously, resulting in increased absorption and emission of energy.
The absorption and emission spectra of a substance are directly affected by temperature. As the temperature increases, the wavelengths of light that are absorbed and emitted by a substance also change. This is due to the fact that the energy levels of molecules change with temperature, resulting in a shift in the absorption and emission spectra.
Greenhouse gases play a crucial role in regulating the Earth's temperature by absorbing and emitting energy. As the Earth's temperature increases, the amount of energy absorbed and emitted by greenhouse gases also increases, leading to a rise in global temperatures. This is known as the greenhouse effect and is a major factor in climate change.
Yes, temperature changes can significantly impact the absorption and emission of light in various materials. Different substances have different energy levels and properties, meaning that they will absorb and emit light differently at different temperatures. This is why scientists must consider temperature when studying the absorption and emission of light in various materials.