Observing strong, rapid twinkling in any celestial object is a certain signature of what?

Answer

Heavy distortion by Earth’s lower atmosphere above the observing spot.

Twinkling is never an inherent property of the celestial body itself; it is a real-time gauge of how turbulent the air mass directly above the observer is.

Observing strong, rapid twinkling in any celestial object is a certain signature of what?
astronomyplanetsatmospheretwinklingflickering