Regarding any evidence for alien life, all anyone has now is “statistics and speculation,” said Larson. “The fact is we have no credible evidence of extraterrestrial presence here on Earth.”
Many scientists consider extraterrestrial life to be plausible, but there is no direct evidence of its existence. Since the mid-20th century, there has been an ongoing search for signs of extraterrestrial life, from radios used to detect possible extraterrestrial signals, to telescopes used to search for potentially habitable extrasolar planets. It has also played a major role in works of science fiction.