Seth Shostak has a piece over at The Guardian suggesting that extraterrestrial life won’t be “squishy” like us, but rather artificially intelligent mechanized beings.
If aliens were ever to visit us Earthlings, he says, they likely wouldn’t be carbon-based lifeforms, or resemble us in any way.
One of the reasons for this is the extraordinary distances they would have to cover just to get here.
“The reason is a simple consequence of the staggering distances to the stars. Even the nearest, Proxima Centauri, is 25tn miles from Earth. Our fastest rockets would take 75,000 years to reach it. Neither humans nor Klingons are built to withstand such trips.”
Mechanized extraterrestrials, however, wouldn’t have to worry about food or oxygen or anything at all, really.
Shostak also says that, while he does believe there’s other life in our galaxy, he doesn’t think extraterrestrials are bouncing around in Earth’s atmosphere right now, nor have they ever throughout our history.