Question

What do perihelion and aphelion mean in astronomy?

Answer 1

Earth orbits Sun in an elliptical orbit..So the distance vary.

Explanation:

When Earth is near to Sun we say it is Perihelion (147.1Million KM)
When Sun is far away from Earth it is aphelion 152.1 million KM. about 152.2 million KM .
picture credit my dark sky .org.