Oracle SYS views missing from DB instance

Hi i have a question but not sure what the problem was and how it happened though. The initial error when i logged in the DB dev machine was ORA-00942: table or view does not exists. Some of the system views that we tried to access gave a ORA-017775: looping chain of synonyms. Then we noticed some of the ALL_* and DBA_* views and functions were missing, which were causing alot of the dependencies and system packages to throw errors. We also noticed that the SYSTEM tablespace has reached 100% utilized space. So my question is, is it possible when the SYSTEM tablespace runs out of space, it would randomly drop the SYS views and functions We also checked the alert logs, seems like it happened during a non-working period. Or is there any logs that i could further check on what happened that caused SYS views and functions being dropped suddenly ? Regards, Thanks