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Why does the sun give out heat?
- Sia Heng Guang (age 8)
Tampines North Primary School, SIngapore
Nice question. I'm not sure whether you are mainly
wondering why the Sun is very hot or how the Sun gives off its heat.
I'll try answering that question first.
Anything that is hot
gives out heat. For instance, if you've ever stood near a bonfire, you
certainly noticed that it was really warm - even if you weren't
actually touching the flames. The same thing happens with the sun. The
sun is basically just a giant ball of hot gas that is incredibly hot.
Its heat is radiated out in all directions and since it's so big and
hot, we can feel it all the way on Earth. For more information on how
heat travels, check out this answer about the ways of moving heat
you are wondering what keeps the Sun so hot, it turns out that the
source isn't a chemical fire like in a stove or a gas heater. It's a
type of nuclear reaction called fusion. We wrote about that in the
answer to What Are Stars?
(republished on 07/19/06)
Follow-up on this answer.