My latest for Sky & Telescope. Obviously written before this latest balloon brouhaha. A reminder that if we're going to take seriously the possibility of alien technosignatures out there, we can't categorically dismiss finding them down here.
https://skyandtelescope.org/astronomy-blogs/cosmic-relief-david-grinspoon/et-on-earth/?fbclid=IwAR1ej794A7RkVPqVKG1dgPtOP2UOY9Zwu5amrJHOBiKTW5rU-iMQwABwOgs&mibextid=Zxz2cZ