I don't think ancient scriptures are nullified if we discover sentient life on other worlds. The scriptures that dominate the religious world are so old that they are like trying to understand cave paintings. Most of their meaning is made up to fit the prevailing prejudices of their various sects. The youngest major religion is about 1400 years old. What was known about the sciences back then compared to now. The Bahai Faith, for instance, writes that the universe is teaming with life unimaginable and that there are other sentient beings capable of recognising God.
