Why Do Comets Sparkle When They Approach the Sun?

Imagine you're walking through a snowstorm on a cold day. Suddenly, the sun comes out and warms your face, the snow starts to melt into water droplets, which catch the sunlight like tiny mirrors. That’s how comets sparkle: they are like big snowy rocks in space, and when they get close to the sun, their ice turns into vapor and dust that shine brightly.