A blackbody emits infrared wavelengths at room temperature. As the temperature increases, the blackbody starts to emit visible light, starting from red to orange, yellow to white and blue with increasing temperature. When the blackbody turns white, it is already emitting ultraviolet radiation.
Stefan's Law states that the total energy radiated by a blackbody per unit surface area is directly proportional to the fourth power of its absolute temperature. This means that as temperature increases, the wavelength of the radiation emitted decreases.
Doppler Effect, or Doppler shift, happens when an observer is moving relative to the wave source - there is a change in the frequency of the wave perceived by the observer. This means that when we are approaching the wave source, we perceive a higher frequency. When we are receding from the wave source, we perceive a lower frequency.
Spectroscopy refers to the dispersion of an object's light into its component colors. By analyzing the light emitted by an object, the physical properties of that object such as temperature, mass, luminosity and composition can be inferred by an astronomer.
Continuous spectrum, as opposed to discrete spectrum, refers to energy at all wavelengths. It is emitted by warm objects. The spectrum of light with missing frequencies is called absorption spectrum. ...