“Working together, tiny stars light up the universe. That’s the power of teamwork!” – anonymous 

Have you ever looked at the sky at night? How beautiful is the sky decorated with the moon and stars? So have you ever wondered why the stars twinkle? 

Before understanding why stars twinkle, let us understand a small scientific term which is refraction. Refraction is the bending of light as it passes from a transparent substance of light ( refraction also occurs with sound, water, and even with waves ). This bending by refraction makes it possible for us to have lenses, magnifying glasses, prism, and rainbows). 

Stars twinkle because there is a lot of difference between stars and earth. So when we view them with the help of a large telescope they appear as pinpoints that get easily disturbed by the earth’s atmosphere. After entering into the earth’s atmosphere each ray from the light of stars gets refracted which makes a slight change in its direction. It happens due to various temperatures and the density of layers in the atmosphere.

There is one more term for star twinkling which looks even more scientific that is ‘atmospheric scintillation’. This term is widely used by astronomers for quick changes in the apparent brightness of a star or even the colour of a star produced by irregularities.

Why are some stars bright and others dim?

Not all stars look the same while watching them from the earth. Because not all the stars are in the same position as us. That means some are near and some are farther away. The closer one to us is the brighter one while the farther a star is dim it will become. Not only distance but size also matters. Larger stars usually shine more brightly, whereas smaller stars don’t.

Constellations 

A constellation is a group of stars that makes an imaginary shape in the sky at night. A constellation is usually named after some mythological characters like ‘ Sapt Rishi’, or animals like ‘Polar Bear’, Objects, pets, people, etc. It usually looks like a game of connecting the dots.

Why don’t planets twinkle?

Planets are close to us as compared to stars so they don’t appear to be point-sized while looking from the earth. When they appear large then the light starts coming from more than one point. This coming light goes under refraction. But as it is mentioned that there are several points from where light comes, these points nullify the twinkling effects and thus planets don’t appear to twinkle.

And also planets are not a source of light. Instead, they reflect low-intensity light teaching them.

Is the sun the largest star?

Do you also think that the sun is the largest star? Although it appears to be. But it’s not true that there are many stars in the galaxy which are much bigger than the sun. The sun is just an average-sized star. The sun appears to be large because of its distance from the earth. It is closer that’s why it appears to be bigger.

What is seeing? 

Even when the concept of shining stars looks romantic and is properly scientific, it can be a nuisance for most people.

Because of this, it becomes difficult to see the image clearly from a telescope. While looking into the sky with the help of a telescope, the image becomes shaky and jumps around.

The extent to which astronomical objects appear to shake and jump around is known as seeing.

Astronomers and people usually complain about a bad seeing 

Did you know?

Stars usually don’t twinkle; they just appear to be because of atmospheric refraction. When starlight enters the atmosphere it gets affected by the wind in the atmosphere and by areas having different temperatures and different densities.

These are the cause due to which we find stars twinkling in the sky 

Key Takeaways 

When starlight enters the atmosphere it collides with gas molecules and gets scattered into the atmosphere. The twinkling of stars is only a natural phenomenon that occurs due to the refraction of light. Refraction of light is also responsible for rainbows and even the human eye works on this principle.

Without refraction, we won’t be able to see clearly. And stars work as pinpoints for us while looking from the earth’s surface as they are very far away and refraction works properly with them. While talking about planets they are very large so light comes from several points which nullify the twinkling effect.

Also published on Medium.