Originally Posted by Blart
Bacteria or some other low lifeform may have hitched a ride to earth on a meteor (then perished upon reaching the atmosphere), which would make for an understandable lack of evidence.
Intelligent life has not visited earth, as there is no reasonable explanation for the lack of evidence.
I would say a very reasonable explanation for lack of evidence is that it would change the worlds perspective on religion and government. It would likely cause mass hysteria worldwide. To me that is a good reason to cover up and deny any visitation.
Millions of reported sightings from all around the world, claims of abductions, cattle mutilations, Roswell, numerous military officials claims they exist, unexplained videos, photos, recorded broadcasts, secret military bases and cover up initiatives, and people on there deathbed who swear they landed but had to take an oath of secrecy.