Here's the breakdown:

* The Sun's Power Source: The Sun is a giant ball of mostly hydrogen gas. Its immense gravity creates incredibly high pressure and temperature at its core.

* Nuclear Fusion: Under these extreme conditions, nuclear fusion occurs. This is a process where hydrogen atoms (protons) collide with enough force to overcome their electrical repulsion and fuse together, forming helium atoms.

* Energy Release: This fusion process releases enormous amounts of energy in the form of light and heat, which is what powers the Sun and provides energy to Earth.

So, the Sun doesn't transform into helium; it uses hydrogen to create helium, and that process is what gives the Sun its energy.