When was the birth of the sun?

Answer 1

The Sun, like other stars, was formed in a nebula, which is like a cloud of dust and gas (mostly hydrogen). These nebulas form stars. They are located at the centre of spiral galaxies, such as our own Milky Way.

In the nebula, dense parts of the clouds undergo gravitational collapse, which mean that they collapse into each other, and they then compress to form a rotating star, like our own Sun.