The Sun didn't "appear" in the sense that it was suddenly created. It formed over a long period of time, along with the rest of our solar system. Here's a breakdown:

* The Big Bang: The universe began about 13.8 billion years ago with the Big Bang.

* Early Universe: The early universe was filled with a hot, dense soup of particles.

* Formation of Stars: Over millions of years, gravity pulled these particles together, forming the first stars and galaxies.

* Formation of Our Sun: Around 4.6 billion years ago, a cloud of gas and dust collapsed under its own gravity, eventually forming our Sun.

So, while we don't have a specific date for when the Sun "appeared," we know it formed within the first few billion years after the Big Bang.