The sun converts 600 million tons of matter into energy every second. This process is called nuclear fusion, where hydrogen atoms fuse together to form helium.

Here's a breakdown:

* Nuclear Fusion: This is the process that powers the sun. It involves hydrogen atoms smashing together at incredibly high temperatures and pressures, fusing to form helium.

* Mass-Energy Equivalence: Einstein's famous equation, E=mc², explains that mass and energy are interchangeable. During fusion, a small amount of mass is converted into a massive amount of energy.

* Sunlight: This energy is released as light and heat, providing the energy that sustains life on Earth.

So, while the sun loses 600 million tons of matter every second, it gains an enormous amount of energy in return, which is what makes it shine so brightly.