Stars (except for the Sun) appear as tiny dots in the sky; as their light travels through the many layers of the Earth's atmosphere, the light of the star is bent (refracted) many times and in random directions (light is bent when it hits a change in density - like a pocket of cold air or hot air). This random refraction results in the star winking out (it looks as though the star moves a bit, and our eye interprets this as twinkling).
Stars closer to the horizon appear to twinkle more than stars that are overhead - this is because the light of stars near the horizon has to travel through more air than the light of stars overhead and so is subject to more refraction. Also, planets do not usually twinkle, because they are so close to us; they appear big enough that the twinkling is not noticeable (except when the air is extremely turbulent).
Stars would not appear to twinkle if we viewed them from outer space (or from a planet/moon that didn't have an atmosphere).
Have you ever noticed how a coin at the bottom of a swimming pool seems to wobble from side to side? This phenomenon occurs because the water in the pool bends the path of light from the coin. Similarly, stars twinkle because their light has to pass through several miles of Earth's atmosphere before it reaches the eye of an observer.
as light passes down through a volume of air, turbulence in the Earth’s atmosphere refracts light differently from moment to moment. From our perspective, the light from a star will appear in one location, then milliseconds later, it’ll be distorted to a different spot. Read more: www.universetoday.com...
I was fooled once by a large star scintillating. Got all excited and thought I had seen a UFO. A member (MAYBE MAYBE NOT) set me on the straight path.
There was also the time a famous astronomer/UFO investigator Dr. Hynek found himself in a police car chasing Arcturus. They said it was moving:
Soylent Green Is People
Two stars are especially known for extreme scintillation -- Sirius and Arcturus -- which are often the source for ATS threads that ask something like "what is that strange object that looks like it is changing color"
I'm sure scintillation had something to do with that.
...I went to Michigan with the hope that here was a case that I could use to focus scientific attention on the UFO problem. I wanted the scientists to consider the phenomenon.
But when I arrived in Michigan, I soon discovered that the situation was so charged with emotion that it was impossible for me to do any really serious investigation. The Air Force left me almost completely on my own, which meant that I sometimes had to fight my way through the clusters of reporters who were surrounding the key witnesses whom I had to interview.
The entire region was gripped with near-hysteria. One night at midnight I found myself in a police car racing toward a reported sighting. We had radio contact with other squad cars in the area. "I see it" from one car, "there it is" from another, "it's east of the river near Dexter" from a third. Occasionally even I thought I glimpsed "it."
Finally several squad cars met at an intersection. Men spilled out and pointed excitedly at the sky. "See--there it is! It's moving!"
But it wasn't moving. "It" was the star Arcturus, undeniably identified by its position in relation to the handle of the Big Dipper. A sobering demonstration for me.