Unless you have a hot line to God, you couldn't possibly know that for sure. I've studied this material for a very long time. There are credible witnesses who have had "close encounters". The gun camera video may not be ET; however, there are objects that are best assumed to be ET.
Why would one believe in something like ET when as of yet there is not one shred of evidence that ET’s exist. I know why, because you want it to be true. Try critically thinking about this subject and then you’ll understand where I’m coming from.