What Makes a Comet ‘Bright’ When It Approaches the Sun?

Imagine a comet as like a dirty snowball made of ice and dust. When it gets close to the sun, the heat melts some of that ice, just like melting snow on a hot day. This creates a glowing cloud around the comet called a coma, and tiny bits of dust fly off and reflect sunlight. That's why comets get so bright when they approach the sun! The more sunlight reflects off the comet, the brighter it looks in the sky.

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Examples

A comet near the sun looks like a glowing snowball in the sky, bright because it's melting and sending out light.
When you see a comet shining brightly at night, imagine that it's like a tiny snowflake getting warm under a giant lamp (the sun).
Comets are like cosmic fireworks, they shine brightest when they’re closest to the sun.

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Categories: Space · comets,solar system,astronomy