Does light exhibit dispersion in a vacuum?

[Starwatcher16]

Does light exhibit any type of dispersion in a vacume?

 

[Bob S]

Dispersion of light, in which velocity is dependent on wavelength, is not expected or observed in vacuum. Dispersion cannot exsist wthout attenuation, based on the Kramers Kronig Dispersion Relations.

 

[astrokreng]

Yes, light does exhibit dispersion in a vacuum. Dispersion is the phenomenon where different wavelengths of light travel at different speeds, causing them to separate and create a rainbow effect. This is due to the fact that light is made up of different colors with different wavelengths. In a vacuum, there is no medium to slow down or affect the speed of light, so it travels at a constant speed. However, when light passes through a prism or other transparent medium, it experiences a change in speed and direction, causing it to disperse and create a spectrum of colors. This dispersion of light is also observed in other situations, such as through water droplets in a rainbow or through a diffraction grating. Therefore, even in a vacuum, light can exhibit dispersion when it interacts with a medium that affects its speed.