Contact: Would we know if it happened?

Forgive my cynicism, but I have to ask: If we received an irrefutable ET signal, would the public ever know?

Suppose it happened tomorrow: Radio astronomers detect an intelligently crafted burst of data lurking in the interstellar noise. According to international SETI protocol, the receipt of such a signal, once verified, would be disseminated among the astronomical community and made public. Indeed, international cooperation might be necessary in order to distinguish a legitimate alien signal from any number of phenomena capable of generating false alarms.

SETI's disclosure scenario only makes sense if the signal in question is of no strategic importance. But, in reality, we have no way of anticipating what an alien intelligence might choose to send us. While many scientists find the prospects of interstellar hate mail slim, we can't immediately rule out the existence of malevolent ETs or cosmic "spam."

A transmitting civilization wouldn't even have to be hostile to pose grave threats to SETI's promise of prompt dissemination. For example, a radio-frequency communiqué might contain data pertaining to a relatively near-term celestial threat such as an impending supernova. In effect, our first signal might prove to be a warning from a galactic emergency broadcast system. While the motive behind the message might be perfectly benign, the effect on our society could prove debilitating.

Which begs the question: How do we distinguish between the sort of lofty, abstract dialogue immortalized by Carl Sagan and less palatable alternatives? More pressingly, how do we make such a determination within a reasonable time-frame?

The arrival of an extraterrestrial signal would almost certainly be fraught with some degree of bureaucratic interference, and it would be the height of naïveté to expect the national security establishment to content itself with idle observation of the proceedings. At some point during the decryption of a candidate signal someone is bound to intervene. If the message seems at all intriguing, I can't help but envision the discovery going underground . . . at least until sufficiently analyzed. (One naturally wonders if the public announcement of an ET transmission would represent the whole signal or a "sanitized" remix.)

Lest my concerns seem like so much "X-Files" paranoia, it's worth considering some of the reasons an ET intelligence might send us a message in the first place. Perhaps, as noted, we're due to experience an unforeseen "existential threat" via gamma radiation or the close approach of an uncharted black hole. Or we may be in the line of fire of someone else's war. More extravagantly, we might discover that our section of the galaxy is scheduled for demolition in order to make room for an astro-engineering project -- in which case our stellar landlords could be sending out a most unwelcome eviction notice (albeit one we can postpone heeding for a few thousand years).

The threats above may seem reassuringly distant to citizens of the West, but the governments of less-developed regions might see things quite differently. While our ET neighbors might be able to take a long-range view, we can scarcely say the same for our own species.

Ultimately, would nation states elect to gamble with their respective economies and socio-political agendas for the sake of imparting knowledge of no apparent practical consequence?

I think the answer is no.

This piece originally appeared at aboutSETI.com.