Anyone who has looked up at the night sky has noticed how the stars shine in a flickering way. This phenomenon is actually the result of a series of refractions and turbulences that occur during light’s journey through the atmosphere.
Light is refracted according to the medium it passes through
Light is refracted as it passes through layers of air of different temperatures and densities in the atmosphere. This process is called fracturing. Turbulence in the Earth’s atmosphere is caused by the displacement of layers of air and bends light from the stars. This is perceived by observers as flickering or twinkling.
The amount of refraction of starlight varies depending on the angle of observation
If the star is directly above your head, refraction is minimal because it intersects the atmosphere at a right angle. But if the star is located close to the horizon, its light has to pass through thicker layers of the atmosphere and the refraction effect becomes more pronounced.
Why don’t planets shine in the same way that stars shine?
The light from planets goes through a similar process, but because of the planets’ large disks, they don’t shine as sharply as stars. It is also possible to observe the planets trembling when they are close to the horizon.
This interesting natural phenomenon offers fascinating details for anyone interested in astronomy and physics.
Source: Sciencing