Nikola Tesla on Extraterrestrial life

“To be sure, we do not have no absolute proof that Mars is inhabited [...] Personally, I have my faith on the feeble planetary electrical disturbances which I discovered in the summer of 1899, and which according to my investigations, could not have originated from the Sun, the Moon, or Venus. Further study since has satisfied me they must have emanated from Mars.”

“During my experiments here [Colorodo Springs 1899] Mars was at a relatively small distance from us, and in that dry and rarified air, Venus appeared as large and bright that it might have been mistaken for one of those military signaling lights...I came to the conclusion that Mars was sufficient to exert a noticeable influence on a delicate receiver of the kind I was perfecting...my ear barely caught signals coming in regular succession which could not have been produced on earth, caused by any solar or lunar action or by the influence of Venus, and the possibility that they might have come from Mars flashed upon my mind.”