Where Does The Sun Get Its Energy?

What makes the Sun shine and where does it get its energy from?

• Chemical reactions or burning gas • Fire or burning air • Gas explosions

If the Sun were just a giant ball of fire, it would have burned out after five billion years, yet it continues to shine.

This is something people assume they know, but don't actually understand.

The Sun is mostly made of protons and neutrons.

• Protons in the Sun dance and move together • When they come close, they bounce off each other • This happens because protons are positively charged

Positively charged particles repel each other due to the electric field - this is why protons bounce apart.

The Sun must be hot enough to make protons move so fast that they sometimes collide despite their repulsion.

When protons smash together at high speed, they stick together and energy is released.

When protons fuse together, the resulting nucleus is lighter than the original protons - some mass is lost.

E = mc², where energy equals mass times the speed of light squared - this shows that a tiny amount of mass converts into a huge amount of energy.

Every second, the Sun loses 4.3 billion kilograms of mass, which is converted into energy.

In the Sun, hydrogen fuses together to form helium through a multi-step nuclear process.

• Two protons collide, and one converts into a neutron while emitting a positron and neutrino • Another proton smashes in, releasing more energy • Two more particles collide, emitting two protons and leaving a helium-4 nucleus

Hydrogen nuclei fuse into helium while losing mass that converts to energy.

Although protons repel each other, they can fuse because the Sun is enormous with so much hydrogen that small collision chances happen constantly.