Space was through parts of history thought to be infinitely empty, however it is not. The reason why it seems infinitely empty is because, we are small, the hollowed space is bigger, the solid matter was, yet still is, bigger than our current amount of empty space. Also, such a long time has passed since the solid matter dissolved this area of space, And it continued to dissolve more solid matter, And to the day i am writing this, more solid matter is still dissolving far away. If we were to travel our hollowed space by flight, at a faster speed than the solid matter is dissolving, We could eventually find the wall of solid matter, Though it would still be dissolving, and due to that, getting close to the wall is somewhat dangerous, For, once again, the remnant element "Fire" was left here by the dissolving process.