Whether aliens could detect our modern civilization depends on what signs they’re looking for—and, crucially, their distance from us

Do Aliens Know We’re Here?

We’ve only been doing what might be called “modern” astronomy for a century or so, and it’s difficult to predict where we might be 100 years hence. The galaxy has been around for billions of years. No one can yet say who else shares it with us or what they’re using to explore. The truth is out there, and turning our search for aliens inside out—by looking from the outside in—may best inform us on how to find it.