On Earth is a phrase that is used to indicate something that occurs or exists in this world. Synonyms for this phrase could include "in existence," "in this realm," "among mortals," "within the confines of our planet," or simply "here on this earth." Alternatively, the phrase could be replaced with "globally," "universally," "worldwide," or "across the entire planet." It could also be modified with descriptors such as "in our realm of existence," "within our physical reality," or "in this plane of existence." These synonyms allow for the same message to be conveyed in different ways, providing a greater level of clarity and variety in written or spoken communication.