So? You ever been in really, really thick clouds. What about clouds of intense smoke?
Moreover, there was quite a bit of spiritual activity going on. You guys just don't seem to understand that your ideas of what is possible are outdated. The more we learn, the more we learn lots of impossible things are possible.
Classical physics says, for example, that if you roll a ball off a table, absent some other force, it will always fall, and has to fall. QM says there is always the slight chance it will roll off into the air and roll back.
Classical physics says if you throw a ball against a wall, it will be bounce back if it doesn't break the wall. QM says there is always the slight chance the ball will go right through the wall and appear on the other side.
Classical physics says a physical object cannot be in more than one place at the same time. QM says that some objects can coexist in a state of superposition.
There's a lot we don't know. A solar eclipse could be possible. More likely, it was a combination of both spiritual and natural forces, so that the clouds were darker than would be the case otherwise due to the sins of the entire timeline of humanity and perhaps other worlds being placed on Jesus during that time.