What causes the image of a star to "twinkle" or scintillate?
A) irregularities in the density of layers of Earth's atmosphere, rapidly refracting the light
B) the flickering fusion process in the stars
C) a purely physiological reaction in the eye
D) None of these choices are correct.

Question

Quizplus · Accepted Answer

The twinkling of stars is caused by the Earth's atmosphere. As starlight passes through the atmosphere, it is refracted by varying densities and temperatures in the air, causing the light to bend and change direction, making the star appear to twinkle.

What Causes the Image of a Star to "Twinkle" or Scintillate