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As poetic and mystical as we may find the twinkling of stars in the night sky, sadly, it is merely an illusion. To shed some light on the matter, we typed "why stars twinkle" into the Yahoo! search box and found a multitude of sites that explained the phenomenon. The twinkling of stars, technically known as stellar scintillation, is due to the very unromantic force known as atmospheric turbulence. Moving pockets of air in the Earth's atmosphere distort the light from the stars. On his Bad
Astronomy site, Phil Plait, our trusted reference for all astronomical inquiries, explains. These pockets of air act like lenses, refracting light in random directions and causing the stars to appear to "twinkle." This cool time-lapse photography helps illustrate the phenomenon. Stars on the horizon will appear to twinkle more than stars directly overhead. This is because the light has to pass through more of the Earth's atmosphere to reach your eye. The colors of a star are also affected by the refraction of the Earth's atmosphere. A star may appear to change colors rapidly due to atmospheric turbulence. Outside the Earth's atmosphere, the stars don't twinkle. That's why the Hubble
Space Telescope is able to capture such clear and amazing photographs of the stars. So why don't planets also "twinkle"? Well, besides the fact that "twinkle twinkle little planet" just isn't as catchy a song title, planets don't appear to twinkle because they are much nearer to Earth than stars. The planets appear much larger to us, so the "twinkling" effect of refracted light is not nearly as noticeable as it is with stars, which are so far away they appear to be only pinpoints of light. However, if the Earth's atmosphere is particularly turbulent, or you are using a powerful telescope, you may notice the planets
doing a little twinkling of their own.
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