by Bob Silberg
Most visitors to the METI website no doubt consider the reasons for wanting to contact intelligent extraterrestrials obvious and compelling. Me, too. But let's acknowledge that some intelligent humans, including no less a luminary than Stephen Hawking, have argued that it is too risky to expose ourselves to possibly hostile beings who are our technological superiors.
Our TV and radio broadcasts, propagating through space at the speed of light, may have already given us away to any nearby aliens. So we can't hide. But should we deliberately draw attention to ourselves?
The usual argument against doing so is that beings with ultra-advanced technologies might come and wipe us out. But there's good reason to think that, if a hail from Earth reached any listeners out there, they would probably be unable to make the trip. And anyone capable of traveling here would be unlikely to want to conquer us.
Think of potential extraterrestrial societies as falling into three technological groups: those unable to send or receive messages across the stars, those capable of such communication but unable to travel to other star systems in a reasonable amount of time, and those who have mastered interstellar voyages.
We are just barely in the second group, with the ability to communicate by radio waves for only the last hundred years or so. It's likely to be a very long wait before our travel time to other stars can be measured in less than centuries. Even the Voyager 2 spacecraft, which zipped past Neptune in 1989 and adds some 1.3 million kilometers (about 800,000 miles) every day to its distance from the Sun, will need 73,000 years to travel as far as our closest star.
So interstellar travel is an extremely tough nut to crack, and it's reasonable to think that far fewer extraterrestrial worlds achieve it than are able to talk but not to visit. If there are multiple homes to intelligence in our galaxy, it seems likely that the main interaction between them is some version of Zoom meetings, with killer lag times.
If any ET civilizations have graduated to Group 3, I'm guessing they got their fill of in-person visits fairly early on. By the time they hear from us, we will be just one more example of primitive alien life they've seen many times before. If we signal them, they might deign to wave back. But a visit? Been there, done that.
And if we do attract interstellar travelers? Would the encounter mimic Earth's history, in which those with superior technology plundered people who were less well-equipped? That seems unlikely.
Human invaders always wanted something their victims possessed: land, riches, sometimes the people, themselves. But what do we have that beings capable of traversing the stars could possibly covet?
Natural resources? Earth offers nothing that could not be obtained back home, with far less effort than trekking the light years to our neighborhood.
Slave labor? Even we have begun to replace human workers with robots and artificial intelligence. Beings who can flit across the galaxy could certainly build machines much more capable than our limited bodies.
Snacks? Notwithstanding The Twilight Zone's "To Serve Man" episode, our wildly different evolutionary paths would almost certainly prevent them from finding us tasty.
Granted, we have no idea what an extraterrestrial mindset might be. But there is no reason to think it would mirror the worst impulses of humans.
In any case, the folks most up for engaging with us are probably those in the second group -- the ones who, like us, can communicate with other star systems but can't yet travel to them. They, too, would likely be more advanced than we are since anyone less advanced wouldn't be able to talk across cosmic distances. But they would not be able to come here and harm us, whatever their desires, any more than we could do the same to them.
These middle-group aliens, being newer to discovering intelligences not of their own planets, would probably be more interested in learning about us in exchange for information about themselves. We would be like pen pals with very, very slow mail service.
Look, when you move into a new home, the safest course of action might be to close the blinds and avoid doing anything that might attract the attention of neighbors who, for all you know, could be serial killers. But chances are you'd be better off reasoning that the risk is low and outweighed by the potential of their becoming interesting and supportive friends.
So yes, let's reach out to our galactic neighbors, if any, and invite them to chat. The super-advanced ones may yawn, but contact with even the moderately advanced ones would blow our socks off.
Bob Silberg wrote about science and technology for NASA and its Jet Propulsion Laboratory for 21 years. However, the opinions expressed here are solely his own and not intended to represent NASA or JPL.