* Nebulae are vast clouds of gas and dust. These clouds are incredibly large and contain a wide range of elements, including hydrogen, helium, and heavier elements.
* Gravity acts as a cohesive force. Even though the gas and dust particles in a nebula are spread out, they are still attracted to each other by gravity.
* Density fluctuations trigger collapse. Over time, small areas within the nebula may become slightly denser than their surroundings. This denser region has slightly stronger gravitational pull, attracting more gas and dust. This creates a positive feedback loop, where more mass attracts more mass, leading to even greater density.
* The core heats up. As the nebula collapses under its own gravity, the gas and dust particles within it collide more frequently. These collisions release energy, causing the core of the collapsing cloud to heat up dramatically.
This process of gravitational collapse and heating eventually leads to the formation of stars. The core of the nebula becomes so hot and dense that nuclear fusion begins, releasing enormous amounts of energy and marking the birth of a star.
