Where does the Sun's energy come from?

Every 1.5 millionths of a second the Sun releases

more energy than all humans consume in

an entire year.

Without the Sun there would be no light,

no warmth and no life.

It's heat influences the environments of all

the planets, dwarf planets, moons, asteroids

and comets in our solar system.

How does a big ball of hydrogen create all that

heat? The short answer is that it is big.

If it were smaller it would be just a

sphere of hydrogen like Jupiter, but the

Sun is much bigger than Jupiter. It would

take almost 1,000 Jupiter's to fill it

up. That's a lot of hydrogen. That means

it's held together by a whole lot of

gravity, and that means there is a whole

lot of pressure inside of it. In fact

the pressure is so intense and the

density so great that the hydrogen atoms

collide with enough force that they

literally meld into a new element... helium.

This process called nuclear fusion

releases energy while creating a chain

reaction that allows it to occur over and

over and over again. That energy builds

up. It gets as hot as 27 million degrees

Fahrenheit in the Sun's core. The energy

travels outward through a large area called

the convective zone. Then it travels

onward to the photosphere where it emits

heat, charged particles and light. That

heat powers the chemical reactions that

make life possible on Earth, allows gases

and liquids to exist on many planets and

moons and causes icy comets to form

fiery halos.

Those particles create a solar wind that

pushes against the fabric of

interstellar space billions of miles away...

And that light travels far out into the

cosmos, just one star among billions and

billions. Not too bad for a big ball of

gas no? Find out more about the Sun at

NASA Space Place.