Here's a breakdown:
* Nebulae: These are vast, interstellar clouds composed primarily of hydrogen and helium, with smaller amounts of other elements.
* Gravity: Gravity pulls the particles of gas and dust in a nebula together, causing the cloud to condense.
* Core Formation: As the cloud collapses, it becomes denser and hotter. Eventually, a hot, dense core forms at the center.
* Nuclear Fusion: The pressure and temperature at the core become so intense that nuclear fusion begins. This is the process where hydrogen atoms fuse to form helium, releasing immense energy that makes the star shine.
So, in essence, stars are born from the collapse of nebulae due to gravity, and they shine because of nuclear fusion happening in their cores.
