What causes a star to twinkle?

Answer 1

The twinkling effect on starlight - properly called scintillation - is caused by refraction in the Earth's atmosphere, due to minor changes in density which result from a difference in temperature. As the air is moved by winds, the exact composition changes and this alters the amount of light refracted to an observer; as more or less light is sent to the observer, its apparent brightness changes, and this is what we call twinkling.
Stars do not actually "twinkle" (as a general statement). The effect that makes them look like they twinkle is atmospheric disturbance (heat dissipation of the atmosphere) - the same way you can see the image of a tree wiggle if you are looking at it over a road baking in the hot sun. NOTE: Some stars (suns) do 'flash' or 'flare' but these are exceptions to the rule.
Light is changed by Earth's atmosphere - and the density of the parts of the atmosphere through which the star's light travels changes quickly.
The stars do not actually twinkle, if you were above Earth's atmosphere they would appear to you as small but stable points of light. It is only when seen through Earth's

atmosphere that the light is distorted and appears to twinkle.

Answer 2

Stars appear to twinkle because of changes in Earth's atmospheric conditions. Before we actually see the light from the stars, it travels through numerous thick layers of the Earth's atmosphere. This causes the light to bend, or refract in various random directions - hence, the twinkling effect.

OK. But the conditions are actually air pockets in the atmosphere which do bend the light.

Answer 3

Stars twinkle because of turbulence in the atmosphere and the variations in refractive index associated with this turbulence. On some nights when the atmosphere is especially calm, the twinkling is greatly diminished.

Answer 4

That is because the atmosphere has moving pockets of warm and cold area. These move back and forth. When a stars light goes threw the atmosphere, it moves back and forth, just like the warm and cold pockets.

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Answer 5

Light from stars does not flicker / twinkle, the apparent flickering is due to the distortion of the light from the star as it passes through the Earth's atmosphere.

Answer 6

Stars shine with a steady light. They only seem to change their brightness due to the movement of air that causes the starlight to get slightly bent, hence the twinkling phenomenon.

Answer 7

because they are giant spheres of gas that radiate the energy from constant nuclear fusion. In other words, they are like the sun, but farther away.

Answer 8

Stars appear to twinkle as their light passes through the atmosphere and is bent as it is affected by turbulence.

Answer 9

Stars appear to be twinkling due to refraction of light in air at different temperatures.

Answer 10

Atmospheric distortion. In space (no air) stars do not twinkle & no one can hear you scream