I was having a conversation with a Mormon woman when it dawned on me that the belief in Joseph Smith's encounter with the "angel" sounds more like an "alien" encounter. I brought this to the woman's attention. I phrased my argument like this. Replace the words angel and alien with the word being and you completely remove religious entanglement. Her response was that this was ridiculous as aliens don't exist. I did not pursue any further "discussion" realizing the futility. While I am not fully confident in the "chariots of the gods" argument there is certainly more circumstantial evidence than the religious arguments.
PS What if the book given to J. Smith was an alien joke book?