Why do stars flicker? And why do some flicker more intensly than others?

I got back home really late yesterday (around 2:30 a.m), and realized I'd forgotten to bring my key with me. I knew that the door opened itself at 3 a.m, so I decided to sit it out. And, since it was a clear sky, my eyes naturally went up there. Don't even get me started on everything that goes through my head when I stare up at the sky during a clear night.

But to get back on topic, I was checking out the stars, and noticed how there was this one pretty small star, that was flickering really intensely. Funny thing is, it was like the only one I could spot that flickered that hard. Obviously all stars flicker (I think?), but this one looked like it was trying to tell me something (if you know what i mean) =p

So, as the question goes, why do stars in the night sky flicker, and why do some flicker way more than others?

I know I could easily google this, but I'd rather start a discussion about it here :-D

(plus, it was way long time ago I posted my last thread in this section. Something like 3 years ago or more? So it's about time. Yes yes, I know it's kinda useless. I was much better at making threads when I was younger for some reason =p)

reply to post by ZikhaN


nevermind

reply to post by ZikhaN

Scintillation.

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).

A more detailed description:
www.astrophys-assist.com...

reply to post by ZikhaN


It's to do with the atmosphere

On a clear, dark night, our eyes can see about 6,000 or so stars in the sky. They seem to twinkle, or change their brightness, all the time. In fact, most of the stars are shining with a steady light. The movement of air (sometimes called turbulence) in the atmosphere of Earth causes the starlight to get slightly bent as it travels from the distant star through the atmosphere down to us on the ground. This means that some of the light reaches us directly and some gets bent slightly away. To our eyes, this makes the star seem to twinkle.

You will notice that stars closer to the horizon will appear to twinkle more than other stars. This is because there is a lot more atmosphere between you and a star near the horizon than between you and a star higher in the sky.

reply to post by ZikhaN


The twinkling of stars, or "scintillation" of stars, is caused by the light from the stars being disturbed by the earth's atmosphere as the light passes through that 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.

Source
Why Do Stars Twinkle?

reply to post by ZikhaN


This is one of the best explanation I have read on this

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...

SOURCE

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.

VeniVidi

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.

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"

Both of these stars are relatively bright, and both of these are usually relatively low on the horizon when viewed from the mid latitudes (where most people on earth live). Being relative low in the sky means that they will be more often viewed through more atmosphere (hence the greater amount of scintillation).

reply to post by ZikhaN

Google is your friend

Better to discuss things that are worth discussing no?

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"

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:

www.ufoevidence.org...

...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.

I'm sure scintillation had something to do with that.

reply to post by Arbitrageur


LOL! That's hilarious. Thanks for sharing.

And thanks to everyone else for your replies, appreciate it a lot. I hoped there'd be something to discuss, but it's so straight forward that there really isn't much to discuss, lol.

Anyway, thanks again! I'll remember this for always :-) Starred all you guys! (accidentally starred "usertwelve" even though he was a total douche =p)

reply to post by ZikhaN


Thanks anyways. Cool jacket!