But could robots be self-sufficient enough to mine and manufacture whatever they need on some distant rock? Aren't we far away from that, if it's even possible?
"We are a very small step away from that right now," Mathews said. "We have 3-D printers (which could manufacture just about anything) and self- replicating systems right now."
We'll be there, he said, "within a couple of years at the most."
That's the starting gate, of course, not the encounter with E.T.. And that encounter will probably come about -- while we're doing other things -- simply because the communications system needed for a fleet of robots just might pick up something interesting.
Mathews has borrowed ideas from astrophysicist Gregory Benford of the University of California, Irvine, and his twin brother, James, a physicist specializing in high-powered microwave technology, as well as James's son, Dominic, a NASA scientist.
The Benfords have argued that the current search for E.T., based on transient signals from something like a television broadcast on another planet, was doomed because that signal would be so weak by the time it reached Earth that it would be undetectable. Most likely, they said, E.T. would use short "blips" of narrowly focused laser beams, probably in the near infrared, to communicate with its own spacecraft, which would most likely be self-replicating robots.
That's also likely to be the kind of communication system that earthlings will use to collect data from their future robots.
Mathews sees this scenario for finding E.T.: A robot belonging to Earth accidentally transits a narrow infrared beam in space. The robot's computer recognizes and captures the data in that short blip. Bingo. E.T. is calling home.
Mathews, and the Benfords, and many other scientists believe that may be how it happens, because any intelligent life would likely face obstacles like ours -- limited resources, many needs competing with space exploration, and problems at home.
"If they are like us, they too have a dysfunctional government and all the other problems plaguing us," Mathews said. "They won't want to spend a lot to communicate with us."
It could take decades, if not centuries, to develop the complete system envisioned by Mathews. But it may not take all that long to find E.T.
It's possible, he said, that extraterrestrial robots are already roaming the outer edge of our solar system. An unmanned spacecraft, with the right communications equipment, just might pick up an electronic bit of data that shouldn't be there.