One reason planets are hard to see is the nearby star swamping the signal. If you choose a particular wavelength and signal encoding, you might get something detectable against this background. It's already been noted that our defense radars and broadcast TV signals are detectable at light-year distances. The proposed probes will be power starved, but they can use a very narrow beam signal. Another possible option is for the probes to communicate with each other. If an occasional heavier probe is included in the mix, it could handle reporting the results back to us. Another advantage of intercommunication is that one probe can tell its followers what to look at. Rich ------------------- Quoting Warren D Smith <warren.wds@gmail.com>:
But anyhow, bottom line is I think the whole "starshot" proposal probably is total no-hope hogwash; it is just that this particular problem is not the reason it is.