1. Outside the earth, there is no atmosphere to scatter sunlight, so the sky appears dark or black to an astronaut in outer space.

    Outside the earth, there is no atmosphere to scatter sunlight, so the sky appears dark or black to an astronaut in outer space.

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  2. At sunrise, the sunlight has to pass through a thicker layer of atmosphere. Blue wavelength is scattered the most, hence blue is scattered away, leaving mainly red colour which reaches our eyes. Hence sky appears reddish.

    At sunrise, the sunlight has to pass through a thicker layer of atmosphere. Blue wavelength is scattered the most, hence blue is scattered away, leaving mainly red colour which reaches our eyes. Hence sky appears reddish.

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  3. Planets are much closer to the earth and can be considered as a collection of large number of point sources of light. If some light from plant is refracted, the effect is not observable and hence planets do not twinkle.

    Planets are much closer to the earth and can be considered as a collection of large number of point sources of light. If some light from plant is refracted, the effect is not observable and hence planets do not twinkle.

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  4. Due to atmospheric refraction, starlight bends from its path. Due to continuously changing atmosphere, starlight varies causing it to twinkle.

    Due to atmospheric refraction, starlight bends from its path. Due to continuously changing atmosphere, starlight varies causing it to twinkle.

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