Why Do Stars Twinkle, but Planets Don’t? Interesting Facts You Force to Know

Why Do Stars Twinkle, but Planets Don’t? Interesting Facts You Force to Know

Have you ever thought about why do stars twinkle, but planets don’t? This question has a very simple answer that maybe we know, or not. The answer is

Why do stars twinkle?

The answer is that 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. They’re so far away from Earth that, even though large telescopes, they appear only as pinpoints. 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.

Astronomers use the term ‘scintillation’ to describe the twinkling of stars. Illustration via Tom Callen of the Cosmonova theater in Sweden Image credit_earthsky.org
Astronomers use the term ‘scintillation’ to describe the twinkling of stars. Illustration via Tom Callen of the Cosmonova theater in Sweden Image credit_earthsky.org

And if the stars closer to the horizon then they will appear to twinkle more than other stars. The reason of this phenomenon is that there is a lot more atmosphere between you and a star near the horizon than between you and a star higher in the sky.

Planets don’t twinkle brighter than stars!

Planets do not usually appear to twinkle, because they are much closer to Earth than the stars. The planets have a more stable image because the light that we can see coming off them is reflected from our own sun, and is much closer! According to the erathsky.org “You’d could see planets as disks if you looked through a telescope, while stars would remain pinpoints. The light from these little disks is also refracted by Earth’s atmosphere, as it travels toward our eyes. But – while the light from one edge of a planet’s disk might be forced to “zig” one way – light from the opposite edge of the disk might be “zagging” in an opposite way. The zigs and zags of light from a planetary disk cancel each other out, and that’s why planets appear to shine steadily”.

The more atmosphere you are peering through, the more stars (or planets) appear to twinkle. Image credit_earthsky.org
The more atmosphere you are peering through, the more stars (or planets) appear to twinkle. Image credit_earthsky.org

You may also watch the video below, the headline of “Why Do Stars Twinkle?”.

Source: Text; NASA, earthsky.org

Image Credit: earthsky.org, science.howstuffworks.com