First: My apologies to both Alex and Nick.

Second: Now that I'm reading the right paper, I see that the points I raised earlier are addressed, if not necessarily all included in the numerical analysis (e.g., the infrastructure "start-up costs").

What I'm struck by, most of all, is the resemblance this paper has to research an author might use prior to beginning a science fiction novel. The hypothetical author is now at the point where he/she is sure "the science works". What remains, then, is emotional and philosopical.

Rose and Wright speak of "we exist" messages as the type better suited to radio transmission. It follows that, owing to the travel time, and the wait time until discovery (if ever), the messages best delivered by inscribed matter could be termed "We once existed."

What motivates a civilization to send forth such message packets, tantamount to monuments, or tombstones? And -- how utterly sobering to contemplate finding one . . .