The Sun and Other Stars
- Earth & Space
- Ages 8–11 · Grades 3–5
What you’ll find out
- The Sun is a medium-sized star that looks brightest because it is closest to Earth.
- The farther away a star is, the dimmer it appears.
- Distances to stars are measured in light-years, so starlight we see left long ago.
No sign-up and no real names. In the lesson you check your understanding as you read, and practise until it sticks.
Why the Sun looks biggest
The Sun is a star, and it looks far bigger and brighter than any other star in the sky. That is not because it is the largest star; many stars are much bigger. The Sun simply looks brightest because it is so much closer to us. A torch shining right beside you is dazzling, but the same torch across a field looks like a tiny dot. Distant stars look faint for the same reason.
Measuring enormous distances
The distances to stars are so enormous that kilometres are not a useful unit. Light is the fastest thing in the universe, yet sunlight still takes about eight minutes to reach Earth, and light from the next nearest star takes over four years. Scientists therefore measure distances to stars in light-years: the distance light travels in a year. When you look at a star, you are seeing light that set off years ago.
Curriculum links: NGSS 5-ESS1-1 · Cambridge Primary Stages 4–6: Earth and space · NCERT Environmental Studies, Classes 3–5