What is Sun's disk?

The Sun’s disk is like the round face you see when you look at the Sun from Earth, it's what makes the sky bright and warm.

Imagine you're holding a big, glowing plate in your hands. That’s kind of what the Sun’s disk looks like to us. It's the visible part of the Sun that we can see with our eyes, just like how you can see the whole face of a plate when you hold it up. The disk is round because the Sun itself is mostly round, like a huge, glowing ball in space.

Think about a lamp in your room. When you turn it on, you see a bright circle of light coming from the bulb. That’s similar to how we see the Sun’s disk, it's just a big, bright circle that lights up our day. The Sun is so far away, though, that we don’t see its whole size, just this round face, or disk, shining down on us.

Sometimes, when clouds cover part of the Sun, you can see the disk getting smaller, like a plate being covered by a hand. That’s why it feels less bright and warm, because not all of the Sun's light is reaching us!