Have you ever gone outside on a clear night and looked up at the sky? You probably saw hundreds of tiny lights twinkling high above you. Some looked bright, some faint, and some seemed to blink like tiny flashlights. Those little lights are stars, and many of them are much bigger than our sun, even though they look small from Earth.

But have you ever wondered why stars twinkle? They don’t blink like lights on a Christmas tree, so what’s going on?

What are stars?

Stars are huge balls of hot, glowing gases. They are mostly made of hydrogen and helium. They shine because of a process that happens deep inside them, which creates a lot of light and heat.

The star that is closest to us is the sun. It doesn’t look like it twinkles, right? That’s because it is very close to us. The other stars are so far away that they look like tiny dots in the sky, even though some are much bigger than the sun.

So, why do they twinkle?

The scientific word for twinkling is stellar scintillation. It happens because of the Earth’s atmosphere. The atmosphere is the blanket of air that surrounds our planet. It is made of different layers, and these layers are always moving and changing.

When the light from a star travels through space and reaches Earth, it passes through these moving layers of air. The air bends the light a little bit this way and that way. This makes the star’s light seem to shift or flicker. To our eyes, it looks like the star is twinkling.

Do all stars twinkle?

Almost all stars twinkle, but some twinkle more than others. Stars that are closer to the horizon twinkle more than stars that are high above. That’s because the light from low stars has to travel through more of the atmosphere, and that causes more bending.

Also, stars that are very bright might not appear to twinkle as much. And in places with less air pollution and light pollution, you can see the stars twinkle more clearly.

What do you think about planets?

Planets do not twinkle as much as stars. That’s because planets are much closer to Earth. Even though they look like small dots in the sky, they are really small disks when seen through a telescope. Their light is steadier and does not get bent as much by the air. So they shine more steadily than stars.

If you ever see a bright light in the sky that does not twinkle, it might be a planet like Venus, Mars, or Jupiter.

Can you see stars twinkle from space?

No. If you were in space, like on the International Space Station, the stars would not twinkle at all. That’s because there is no atmosphere in space to bend the light. The stars would shine with a steady and calm glow.

Twinkling stars in stories

For thousands of years, people have looked up at the stars and made up stories about them. Some stars are part of constellations, which are groups of stars that form pictures in the sky, like the Big Dipper or Orion. There is even a famous song we all know: Twinkle, twinkle, little star. Long ago, people noticed how stars seemed to sparkle in the night sky.

Final sparkle

So, the next time you look up and see stars twinkling, remember that it is not the stars blinking at you. It is Earth’s atmosphere playing with its light. It’s like a magical show happening every night, right above our heads.

Keep looking up. There is always something amazing waiting in the sky.