If they're out there, we'd better pray that the aliens aren't sophisticated enough to watch our science fiction television programming.
In a letter to the Daily Telegraph, former BBC News website science correspondent Dr David Whitehouse raised the possibility that transmissions from earth could draw the attention of "malevolent aliens", were any to exist.
But ordinary television and radio broadcasts can also travel out of earth's atmosphere and through space, albeit quickly becoming mind-bogglingly diffuse and hard to pick up.
Perhaps not to the DALEKS!
There isn't much in this BBC article on the fact that Earth is quickly becoming a small radio star that isn't new to people who've read a lot of Carl Sagan, but as Sagan pointed out, it is rather disturbing that our likely introduction to alien races will be the broadcasts of Hitler's Nurnberg rallies.
On a lighter note, and you should watch this with speakers on, many, many thanks to Mark Randazza, whose link to this video has already amused me about ten times in the past 24 hours:
Funniest thing I've seen in a dog's age.