Outer Space: Why alien 'megastructures' may hold key to making contact with extraterrestrials

For nearly 70 years the scheme favored by most scientists has been to look for signals — radio transmissions. That’s the classic approach of SETI (the search for extraterrestrial intelligence), and frankly, it makes sense. Radio can easily traverse light-years, and the technology for detecting it is well known and highly sensitive.

But is looking for signals really the best plan? Is it possible that we’re making the wrong bet?

There’s an attractive alternative: searching for physical artifacts — alien structures. We’re not talking about crop circles or other odd phenomena here on Earth. We’re talking about massive engineering works that an advanced society has constructed somewhere in space.

Why search for artifacts? Because it eliminates the requirement that the aliens have chosen to get in touch — to transmit radio signals our way. Sure, maybe they’d want to do that, but then again maybe they’d rather lay low. If you’re not sure you’re the Milky Way’s top-dog society, you don’t want to bet the farm by assuming that the alpha aliens, wherever they might be, have good intentions. Silence could have survival value.

Read more: Why alien 'megastructures' may hold key to making contact with extraterrestrials | SETI Institute