Why is it warm when the Sun shines?

Step outside on a sunny day and you can feel the Sun warming your skin. But the Sun is really, really far away. How can something so far make you feel cosy?

The Sun is a giant fireball

The Sun is an enormous, glowing ball of super-hot gas — so big that a million Earths could fit inside it! Deep in its middle, it makes a gigantic amount of energy, and that energy pours out as light and heat.

Sunshine carries energy

The energy travels all the way to Earth as sunlight. Light can fly through empty space without anything to carry it, a bit like a super-fast invisible delivery.

When that sunlight lands on you — on your hand, your cheek, the pavement — the energy turns into warmth. That is the cosy feeling you get when you stand in a sunbeam.

Why does shade feel cooler?

In the shade, something is blocking the sunlight — maybe a tree or a wall. Less sunlight reaches you, so less energy turns into warmth, and you feel cooler. That is why a shady spot is perfect on a hot day!

Wonder fact: Sunlight takes about 8 minutes to travel from the Sun to your face. So the warmth you feel left the Sun before you even went outside!