How do astronomers see the inside of the sun when they can't even go near the sun at all? You know when they show the core of the sun, the photosphere of the sun and etc. how could they see that? They can't even get a good picture of Mercury since it is so near the sun and since they can't get a good picture of Mercury then how could they get a picture of the sun?
We cannot see inside the Sun. We can only observe the surface. What's known about the Sun's interior comes from models that use the laws of physics to predict the internal conditions. There are a number of different observations (such as vibrations on the Sun's surface, detections of solar neutrinos, and measurements of elemental abundances on the surface) that allow astronomers to test and refine these models.
Regarding how the Sun can hinder one's ability to observe Mercury: That's actually a somewhat different situation. In that case, the problem is that the light from the overwhelmingly bright Sun can drown out the light of what you're trying to observe (Mercury). But if the Sun is what you're trying to observe, then all that light is actually a *good* thing.
This page was last updated June 28, 2015.