When light waves are incident on a medium for
example on gas, the waves encounter molecules and atoms of the gas. The
light wave deviates from its path and gets scattered in all possible
directions. The light wave is absorbed by the molecules and radiated
back in all directions. This is called scattering of light radiation.
These molecules are called the scattering centers.
In a solid or liquid too, the molecules or particles that radiate the incoming radiation energy in
all directions are called scattering centers.
Almost all gas molecules are scattering centers.
there is laser beam (highly directed) between two points far from you
and across us, we are able to view this beam because of scattering of
laser light into our eyes.
see diagram too.