Complex sentence: Pearl expresses her incredulity over the fact that they managed to bubble something as big as the Cluster, and Steven simply replies that they had a little help, as the Cluster is seen peacefully laying deep in the Earth inside of Steven's bubble.
Split into simpler sentences: Pearl expresses her incredulity over the fact that they managed to bubble something as big as the Cluster, and Steven simply replies that they had a little help. As the Cluster is seen peacefully laying deep in the Earth inside of Steven's bubble.