Why Some Stars Look Brighter Than Others

Science · Space Systems & Earth's History · ages 10-11

Name ______________________ Date ____________

You turn on a torch right next to your face, then a friend far across a field turns on the same torch. From your friend's side, how does it look?
- Bright, like a big glow
- Dim, like a tiny point of light
- Exactly the same as up close
The sun is actually just a star. Why does it look far brighter than any other star in the sky?
- It is much closer to Earth than the other stars
- It is the only star that is really on fire
- It is much bigger than every other star
The sun is a star, the same kind of object as the stars you see twinkling at night.
Circle one: True False
Two stars are actually the same true size and true brightness, but one looks much dimmer in our sky. What is the most likely reason?
- The dimmer star is much farther from Earth
- The dimmer star is not a real star
- The dimmer star stopped shining
Look at the chart. It shows how bright two campfires look from where you stand. Which one is probably closer to you?
- Fire A
- Fire B
- They must be the same distance
A classmate says the sun must be a giant compared to every other star, because it looks so much brighter. What is the better explanation?
- The sun only looks huge and bright because it is so close to Earth
- The classmate is right, the sun really is bigger than all other stars
- Brightness has nothing to do with size or distance
Imagine the sun swapped places with a star that is much farther from Earth, keeping its true size and brightness the same. What would happen to how the sun looks from Earth?
- It would look exactly the same as it does now
- It would look even brighter than it does now
- It would look much dimmer than it does now
Star X is smaller than Star Y, but Star X looks brighter in our night sky. What is the best explanation?
- Star X is probably much closer to Earth than Star Y
- Star X must secretly be bigger than Star Y
- The two stars must be the same distance away

Answer key

For grown-ups. Fold this page away before handing over the rest.

Why Some Stars Look Brighter Than Others W1-mt_ZhKuYCbXz1-s1

Dim, like a tiny point of light · Light spreads out the farther it travels, so the same torch looks dimmer from far away.
It is much closer to Earth than the other stars · Every star is far away, but the sun is close enough that its light looks huge and bright.
True · The sun is a star. It just looks completely different because it sits so much closer to us.
The dimmer star is much farther from Earth · When two stars are equally bright up close, the one that looks dimmer to us is usually the one farther away.
Fire B · The brighter something looks, the closer it usually is, just like the torch example.
The sun only looks huge and bright because it is so close to Earth · Many stars are actually bigger than the sun. The sun just looks brighter because it is nearby.
It would look much dimmer than it does now · Since apparent brightness depends on distance, moving the sun farther away would make it look far dimmer, like any other distant star.
Star X is probably much closer to Earth than Star Y · A smaller star can still look brighter if it sits much closer to Earth than a bigger, farther star.