Planets and moons don't shine on their own. They appear bright because they reflect sunlight. Here's how it works:

* Sunlight: The Sun is a massive star that produces its own light and heat.

* Reflection: When sunlight hits a planet or moon, some of it is absorbed, while some of it bounces back off the surface.

* Brightness: The amount of light a planet or moon reflects depends on:

* Surface material: Rocky surfaces reflect less light than icy surfaces.

* Atmosphere: A thick atmosphere can scatter and absorb light, making the planet appear dimmer.

* Angle of sunlight: When sunlight hits the surface at a more direct angle, more light is reflected back.

So, what you see as the "shine" of a planet or moon is actually the sunlight that's bouncing off its surface.