Science fiction movies frequently make it seem as though hostile extraterrestrials might be able to sneak through Earth’s atmosphere, emerge from the clouds without warning, and start wrecking shit. But is it really possible that spaceships could suddenly appear out of the blue and the vast blackness of space previously unnoticed by the myriad instruments on the ground? Depending on the aliens’ level of technological sophistication, one can argue that almost anything is possible. Humans have pointed a lot of sensors skyward, but it’s not clear they would really give us a proper heads up before our extraterrestrial guests arrive.
It sort of depends on exactly what we’re looking for. The search for extraterrestrial intelligence, better known as SETI, has been fruitless so far, but we keep investing and more and more money towards projects aimed at answering whether or not were alone in the universe. That investigation basically revolves around detecting signals that technologically advanced extraterrestrials exist. And that also means the instruments we can use to observe space lets us see farther into the universe than ever before. How far exactly? Douglas Vakoch tells Inverse that the answer has more to do with defining “see” than with arriving at a specific number.
The irony of this is obvious. To read more, click here.