What stars are — Astronomy, 7–10 years
Stars are enormous, hot balls of gas that make their own light. Our Sun is one star among many.
A star is a distant sun
A star is a huge ball of very hot gas. It makes light and heat inside itself, so it does not need a nearby lamp to shine. The Sun looks much bigger because it is far closer to us than every other star.
Why stars look like points
People needed to explain why bright points appear in the night sky and why the Sun is different from a small lamp. The answer is distance: stars are huge, but they are so far away that their light reaches us from one tiny-looking direction.
Comparing the Sun and Sirius
Look at the Sun and Sirius. The Sun is about 150 million kilometres from Earth, while Sirius is about 81 trillion kilometres away. Sirius can still look like a bright point because it makes lots of light, but its great distance makes it seem tiny.
The star-sized mistake
It is natural to think the Sun is a big object and the other stars are tiny lights, because that is how the sky looks. In fact, many stars are as large as the Sun or much larger. They only look small because they are enormously farther away.
Stars as clocks and guides
For thousands of years, people have watched stars to tell the time of year and to help find directions at night. Sailors used particular stars to guide ships. Today, astronomers study starlight to learn about a star’s temperature and what it is made of.
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