* We can't see directly through the sun. The sun is incredibly bright and hot, and its light blocks our view of anything on the other side.
* We can't send probes directly through the sun. The intense heat and radiation would destroy any spacecraft.
So, how do we know?
* Orbiting planets are predictable: We've studied the orbits of planets in our solar system. If there were planets on the other side of the sun, we'd see their gravitational influence on the planets we already know.
* We can detect planets indirectly: Techniques like the transit method and radial velocity method allow us to detect planets even if we can't see them directly. These methods look for wobbles in the sun's movement or dips in its light caused by a planet passing in front of it.
The bottom line: While we can't see directly through the sun, we have no evidence suggesting planets exist on the other side of it. Our current understanding of the solar system suggests it's unlikely, but science is always evolving!
