Why do stars twinkle?

Question

Why do stars twinkle?

Answer 1

Stars do not actually twinkle they just look like they're twinkling because of the moving clouds  we see in the sky...when those clouds cover the stars then uncover it they look like they're twinkling but actually they're not...example when you put a cover against a light at a far distance the light will seem to disappear but when you move the cover away the light will be visible again do it fast and many times then the light will look like that it's twinkling..well that's what i know i wish i could help.

Answer 2

Five very simple questions asked within a few minutes - and the answers are so easy to find in your text book or online (wikipedia, space.com, astronomy.com are all decent sites).

Answer 3

Jessica is pretty much on the money.

This effect is due to the varying thicknesses of air the light, from the star, must pass thru to reach us. Heat....'thermals'....cause the refractive index of the air to change causing the flickering effect. This can happen near the earth's surface or in the near atmosphere where temperature shifts causing weather patterns take place.

It can, obviously be caused by things getting in the way, like clouds, but this is trivial and not associated with 'shimmering' stars in the night sky.

Answer 4

It is a shimmering effect caused by the air. It is kind of like the shimmering you see near hot objects sometimes, only not as strong. The air does that almost all the time, but the twinkling of the stars is usually the only way to notice it.

Answer 5

Twinkling is closely related to what astronomers call 'seeing' (atmospheric blurring of an image). Both are caused by the turbulent cells in the upper atmosphere: these are little pockets of air that have different density, temperature, humidity etc. than the surrounding air. The density contrast causes refraction, and as different cells move in and out of your line of sight, the image of the star (which is point-like) is seen to move around from one second to the next. This movement is seen as twinkling by the eyes; if you take a photograph over several minutes, as astronomers often do, then the image becomes blurred. The seeing (this blurring) can be as good as ~0.5 second of arc at the best astronomical sites on Earth, while the worst I've ever seen at a professional observatory was about 8 seconds of arc (we gave up observing that night; more typically, 2 seconds of arc would be considered bad by today's professional astronomers). 1 second of arc is 1/3600th of a degree.

So why don't planets twinkle? This is because, even though they may look point-like to naked eyes, they are actually much bigger than the typical seeing. This means that you observe the combination of light which has passed through different atmospheric cells. Thus, the turbulent effects are averaged out, making the planets look steady.

Answer 6

Stars twinkle because we are viewing them through thick layers of turbulent air in the Earth's atmosphere that slightly distort our view. The closer the star is to the horizon the more it appears to twinkle. This is because the light of stars near the horizon has to travel through more of the earth's atmosphere than the light of stars overhead and so is subject to more distortion. If you were to view the stars from the moon the starlight would not have to travel through an atmosphere and the stars would appear rock steady.