AstronomyThe Sun Is a Star That Warms and Lights Us
Nova floats beside a bright sunny window, holding up a glowing yellow star model and pointing outside at the blue daytime sky where the Sun shines above green treetops.
- Identify the Sun as the closest star to Earth.
- Explain that the Sun gives Earth light during the day.
- Explain that the Sun gives Earth warmth.
- Compare daytime (Sun up, bright and warm) with nighttime (Sun down, dark and cool).
Key terms
- Sun
- Our closest star, which gives Earth light and warmth every day.
- star
- A huge ball of hot glowing gas that makes its own light in space.
- sunlight
- The light from the Sun that reaches Earth and makes the day bright.
- warmth
- The heat we feel on our skin, such as the Sun warming a sunny day.
- daytime
- The bright part of the day when our side of Earth faces the Sun.
The Sun Is a Star Too
The Sun is the very same kind of object as the twinkling stars you see at night. It is a giant ball of hot, glowing gas that makes its own light. The Sun looks much bigger and brighter than other stars only because it is so much closer to Earth. The other stars are far, far away, so they look like tiny dots even though many are huge too.
Day, Night, and a Spinning Earth
The Sun's light and warmth reach Earth all the time, but we do not always face the Sun. Earth slowly spins like a top, turning all the way around about once each day. When our side faces the Sun, we have bright, warm daytime. When our side turns away, the sunlight cannot reach us, so it becomes dark and cooler. That turning is what makes day change into night.
Worked examples
Explain what kind of object the Sun is.
- Remember that stars are balls of hot glowing gas that make their own light.
- The Sun makes its own light and is a ball of hot gas.
- It only looks bigger because it is the closest one to Earth.
Answer: The Sun is a star, the closest star to Earth.
Tell why it gets dark at night.
- Recall that Earth spins slowly like a top.
- When our side turns away from the Sun, its light cannot reach us.
- So that side of Earth becomes dark, which is night.
Answer: It gets dark because our side of Earth turns away from the Sun.
Activity
Sort each picture into the correct bucket — does it happen because of the Sun?
Practice
Decide whether a warm sunny sidewalk happens because of the Sun.
Tell why the Sun looks bigger than the stars at night.
Common mistakes to avoid
- The Sun turns off at night.The Sun never turns off; our side of Earth just turns away from it.
- The Sun is a giant light bulb in the sky.The Sun is a real star made of hot glowing gas, not a built light bulb.
Check your understanding
What is the Sun?
What does the Sun give Earth during the day?
Why does it get dark at night?
Recap
The Sun is our closest star, a giant ball of hot glowing gas that makes its own light. It gives Earth sunlight and warmth every day. The Sun looks bigger than other stars only because it is so close. As Earth spins, our side turns away from the Sun, which makes night dark and cooler.
Reflect
Now that you know the Sun is a star, how does looking at it feel different?