As a child, I've read that stars ignite during a so-called "nuclear flash". I understood this as a very violent outburst of energy from the sun, causing all dust between the protoplanets to be blasted away out of the solar system. The gas and dust clots which were too heavy stayed but were melted because of the high temperature, they collided and formed the aforementioned protoplanets, who then cooled down, the fact that they started as melted clots also explains the reason that planets are round.
Now that I'm (a bit) older, one thing is puzzling me: I have the impression of the "nuclear flash" as a very strong explosion, followed by the sun behaving normally almost immediately after, but that does not feel right anymore: I now have the idea that both processes (the "nuclear flash" and the sun's temperature decrease) both happen together, so I wonder:
- Is the "nuclear flash" indeed a very short explosion, which is finished in a matter of minutes or even seconds or is the birth of a star more a slow process, taking thousands of years before even reaching the "normal" temperature?
- Is the sun's temperature decrease after the "nuclear flash" very short or does it also take very long?