An excerpt from ”Bulletproof Blues”…
Earth has been visited by aliens many times in its history, although few people are aware of this. Most of these visits were well before 3000 BCE, which is when humans began recording history. Some may have even been before the evolution of Homo sapiens approximately 200,000 years ago.
However, since the beginning of recorded history extraterrestrials have only openly visited Earth twice: Draconian, who came to our world in 1951 after escaping the destruction of his home planet (inspiring the film The Day The Earth Stood Still), and the Isopterans, who invaded Earth in 2009 (inspiring numerous “alien invasion” films in the following years). Some experts believe that a third group of aliens, the Shran, has visited the Earth, but there is little evidence for this, and the claim is disputed.
Even though the Isopterans landed on five different continents, and the conflict was reported by every news medium, a significant number of people do not believe that extraterrestrials exist (roughly 30% of the polled populace of the Unites States, for example).