The controversy arose when a couple of years ago, retired NASA Chief Scientist James L. Green spoke about Mars and the alleged extraterrestrial life on it.
Before moving on to Dr. Green’s statement, it should be known that NASA has acknowledged that there may be interference from alien civilizations in the history of the Earth. In 2014, NASA published a book titled Archeology, Anthropology and Interstellar Space which looks at extraterrestrial interference in human history. It notes the possibility that some of the rock art on Earth may be of alien origin. It was edited by Douglas Wakoh, director of the Search for Extraterrestrial Intelligence (SETI) Division.
Also, in fact, it would take only 10,000 years for the traces of human presence to disappear from the planet, which is very short period compared to the age of the Earth.
If such a civilization had once existed,
then its traces would not be so obvious – given that more than 4
billion years of the Earth is a sufficiently wide range for the
evolution (and extinction) of intelligent life...<<<Read More>>>...