Question

Stars can emit their own light but planets cannot .why?

please answer fast it's urgent

Answer 1

Because Planets Do not have nuclear fusion, they do not produce their own light. Instead, they shine with lightreflected from a star. 

Answer 2

Stars has heat in plasma state (fourth state of matter) and when heat generate in much amount then it glow. while planets do not have nuclear fusion, they do not produce their own light. Instead, they shine with lightreflected from a star. if we see in night we found them golwing but in reality they reflect the light from sun ( sun is also a star).