The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as visible light, ultraviolet light, and infrared radiation. It is by far the most important source of energy for life on Earth.

Is the sun the oldest thing?

Some of the pre-solar grains turned out to be the oldest ever discovered. Based on how many cosmic rays had interacted with the grains, most had to be 4.6-4.9 billion years old. For comparison, the Sun is 4.6 billion years old and the Earth is 4.5 billion.

How OKD is the sun?

Our Sun is 4,500,000,000 years old. That's a lot of zeroes. That's four and a half billion.