Seth Shostak, for the NYTimes:

The aliens could very well be out there. And that realization has spurred a call by some for broadcasts intended to elicit a communication from at least the nearest other star systems. But we know nothing of the aliens’ possible motives or behavior. Therefore, it’s conceivable that betraying our existence might prompt aggressive action from space.

Broadcasting is likened to “shouting in the jungle” — not a good idea when you don’t know what’s out there. The British physicist Stephen Hawking alluded to this danger by noting that on Earth, when less advanced societies drew the attention of those more advanced, the consequences for the former were seldom agreeable.

In my opinion, living in fear — acting under the assumption that the very worst possibility is probable — is a waste of our time as galactic citizens. Even if malevolent forces do exist, as the article says, mincing words is unlikely to lessen our risk. Were it up to me, we’d be broadcasting night and day, to all points.