Why do stars twinkle and change colors and shapes?

Question

I was in Maine last week and I looked up in the sky and saw a "star" twinkle, change colors and shapes. Was I seeing thinkgs? What was that?

Answer 1

Instability in our atmosphere causes erratic refractions of light from

stars and planets.imagine if you will,looking at an object beyond a hot

bar-b-que.

this distortion makes stars apear to 'twincle'

Answer 2

Stars twinkle, due to the variations of visual "turbulence" in our atmosphere as the light passes through it, on it's way to your eye.  This phenomenon is enhanced even more so when stars are near the horizon.  

But, why, then, do planets not appear to twinkle?  

Well, planets are much closer, and even though they look like pinpoints of light, upon magnification, they can be resolved into "discs" of light.  The stars are so distant, that they remain pinpoints even at high magnifications.  Since the planets cover more of our sky (even though it's not detectable without telescopes) they can compensate for the subtleties that interfere with the light as it passes through our atmosphere.

The star isn't really changing color at all...  even though, from my latitude, Antares (a particularly red star) when low in the horizon will appear to twinkle red and blue...  this is more of the atmosphere messing with us...  Notice, that the stars will not appear to behave  this way in space, or from a planet without an atmosphere.

As far as shape goes, I am mystified.  Stars should ALWAYS look like a pinpoint of light (from earth)...  sometimes a really bright one might appear to have "rays" emanating from it, but this has more to do with your vision...  think about when you are looking at a streetlight.  Then you squint at it.  Suddenly, the light appears to smear in a few directions.

Answer 3

The Earth's atmosphere distorts the light coming from the stars! Just like when you're at the bottom of a pool filled with water and you see the water moving and distorting the image behind it!

Answer 4

Those effects are caused by our dirty, sloppy, messy atmosphere.  From space none of that happens, and it is one of several reasons why observatories wind up atop high mountains, to get away from as much as possible of our dirty sloppy messy atmosphere.