Here's why:

* Stars are not on fire in the traditional sense. They produce light and heat through nuclear fusion, a process where hydrogen atoms fuse together to create helium, releasing tremendous energy.

* Twinkling is caused by Earth's atmosphere. The light from stars travels through our atmosphere, which is constantly moving and has different densities. These fluctuations in density cause the light to bend and refract, making the star appear to twinkle.

Think of it like looking through a shimmering pool of water. The light from something under the water appears to dance and flicker because of the movement of the water. Similarly, the light from stars is distorted by the moving air in our atmosphere.