If you've ever pondered what you would say to an alien, you may get that chance between 7:30 and 8 p.m. PT tonight.

That’s the goal of Tweets in Space, a project – sorry, “performance art piece” – by two guys with starry, starry eyes. As part of this year’s International Symposium on Electronic Art in New Mexico, Scott Kildall and Nathaniel Stern will spend 30 minutes capturing every tweet with the hashtag #tweetsinspace for later transmission into the (much) wider Twitterverse.

Using a radio transmitter in Florida, they plan to beam our messages to GJ667Cc, an exoplanet that might, just maybe, possibly, have the required attributes that would allow it to theoretically support life (as we know it). Four to six weeks after Friday’s event, the planet will move into alignment (just barely) with the transmitter. And that’s when Kildall and Stern, a multimedia artist and associate professor at University of Wisconsin-Milwaukee, will hit send.

“It all goes,” says Kildall, the new media exhibit developer for the Exploratorium. “Even political positions I don’t agree with: ‘Vote for Romney,’ ‘Vote for Obama.’” (All except hate speech, he added. We might not want to betray our baser nature to the ETs.)

But it’s a long shot in more ways than one. The target is 22 light-years away. That means 44 years minimum before we know if they’ve succeeded.

If there’s even a chance. Reality check, say radio astronomers: There isn’t. “We have absolutely no hope of actually being heard,” said James Benford, founder of Microwave Sciences and longtime skeptic of the Search for Extraterrestrial Intelligence (SETI). He did the math for Wired. With the Deep Space Communications Network’s Florida dish, which is small and low-power by industry standards, the signal might be detectable up to seven times the distance to Pluto, assuming the aliens have the same technology we do.

“That’s nowhere,” Benford said. “That’s not getting anywhere near interstellar distances.”

But Seth Shostak, a senior astronomer at the SETI Institute, says it's theoretically possible that the theoretical aliens on the target planet could pick up the signal from Florida. “If they have a receiver the size of Nebraska, then they can pick this up,” he said. “You have to hope the aliens have spent more money on their antennas than we have on ours.” (Incidentally, a receiver the size of Nebraska would cost in the hundreds of billions. In U.S. dollars, that is. “What’s your currency/exchange rate, aliens? #tweetsinspace”)

What’s more, most astronomers put the estimate for nearest ETI at no fewer than hundreds of light years away, and it’s probably closer to thousands. Twenty-two would be miraculous. We'd have far better odds of floating a message in a bottle from San Francisco to China.

But even if their project’s more stunt than sound science, Kildall and Stern are (unintentionally) participating in an ongoing, still-controversial debate: whether or not we should be actively messaging aliens in the first place. Could it endanger Earth and the fate of mankind? That’s not such a kooky, far-out question. People like Benford, along with sci-fi author David Brin, UCLA professor and best-selling author Jared Diamond, and Stephen Hawking, have argued for years that we should be sitting silently in our cosmic corner, biding our time and weighing risk factors before we go flamboyantly yoo-hooing to the entire universe.

If the aliens are sufficiently advanced to receive and translate our messages, shouldn’t we be afraid they'd also have the technology to warp to our location, eat our children, and blow up this precious planet?

The other camp, which includes the SETI Institute and the historically optimistic, pro-METI (Messaging Extraterrestrial Intelligence) Russians, argues that we’ve already given away our position a thousand times over, thanks to decades of signal leakage. As Shostak put it, “If they’re looking our way, they will already know.” So we might as well continue. Heck, we might as well start sending them everything. Encyclopedias! Beatles songs! The Google server!

Benford disagrees. In a recent paper, he showed that no signal, not now or 50 years ago, could ever be detected by ETI. That doesn’t mean the prospect of METI doesn’t worry him. In a century, we’ll have the technology (and plenty of bored trillionnaires to fund it) to build radio transmitters big and powerful enough to send detectable messages. Just as likely, Benford says, we’ll be sending energy to and from satellites, a practice that could considerably brighten Earth’s position in the cosmos. The thought worries him. He wants us to stay dark and silent. At least until we know better.

The conversation continues. Shostak is publishing a paper now on whether transmissions to space are dangerous. (“No,” in brief.) Benford is similarly engaged from the other side. The two men, though old colleagues, can still be heard gleefully bad-mouthing each other, both privately and in public forums.

Though Kildall and Stern remain optimistic that their Tweets in Space have a chance of succeeding – they believe they have better odds at this than winning the lottery – they also allow for occasional moments of realism. “It’s working with potential and imagination, rather than actuality,” Kildall eventually conceded.

Shostak, for one, has no problem with projects like this, of which there’ve been a few in recent years. He sees it as an introspective exercise. “It’s interesting not for the aliens. It’s interesting for us,” he said. “What do people want to say?”

Find out tonight. Or don't. The aliens will never know. We think.

Image: Banner ad for Tweets in Space. Used with permission.