The scheme requires reception by an advanced civilization during a narrow window of opportunity; the radio waves have no effect on the billions of dead planets all around. A probe, on the other hand, presumably would be able to affect any system.
Since we observe so few life-filled planets or signals out there...
The scheme requires reception by an advanced civilization during a narrow window of opportunity; the radio waves have no effect on the billions of dead planets all around. A probe, on the other hand, presumably would be able to affect any system.
Since we observe so few life-filled planets or signals out there...