No, planets do not have their own light. They are not luminous objects like stars. Instead, planets shine by reflecting the light of their parent star, typically the Sun.
When sunlight falls on a planet, its atmosphere and surface reflect a portion of that light back into space. This reflected light is what allows us to see planets from Earth. The amount of light reflected by a planet depends on various factors such as its size, composition, and the nature of its surface.
Different planets exhibit different levels of reflectivity. For example, Venus is highly reflective due to its thick cloud cover, while Mercury has a relatively low reflectivity because its surface is predominantly rocky and lacks a substantial atmosphere.
Planets also do not emit their own light through processes like nuclear fusion, which is how stars generate their energy and light. However, some planets, such as gas giants like Jupiter and Saturn, can emit a small amount of internal heat in the form of infrared radiation due to their internal processes and residual heat from their formation.
In summary, planets do not generate their own light but rather reflect the light of their parent star, which is why they are visible to us.