"…most people know but don't realize is that the world is almost entirely solar-powered already. If the sun wasn't there, we'd be a frozen ice ball at three degrees Kelvin."
The Sun is composed primarily of Hydrogen (74.9%) and Helium (23.8%) and a few other heavier elements (metals) like Oxygen, Carbon, Iron etc. This proportion changes over time as the Sun converts Hydrogen to Helium in its core through Nuclear Fusion.
Like Earth, Sun also rotates about its axis. Its sidereal rotation takes 25.05 days to complete at the equator and about 35 days at the poles. Why such a differential rotation? Because Sun is a molten ball of fire. The fluids near the poles move progressively slower than the fluids at the equator.