But for those advocating active SETI, or METI, passively looking at the stars is a fools errand, we need to be advertising our presence to the cosmos! We should be blasting unambiguous signals to the stars right now to stand a chance of making "first contact" and proving, once and for all, that there's life -- intelligent life no less -- beyond our interstellar shores.
There have been various METI efforts, but, as pointed out by Gertz, these have been done largely without regulation or discussion with the international community and could be considered to be "unwise, unscientific, potentially catastrophic, and unethical." He even goes as far to say that the current METI methodology is little more than a faith-based roll of the chamber during a game of Russian Roulette.
"Sending a message without a practical plan in place to receive a return message, leads to the conclusion that METI transmissions are like a Hail Mary, they have more in common with a faith based religion than with science," he writes.
ANALYSIS: Shoot Aggressive Aliens With Lasers to Defend Earth
Indeed, there are many that oppose the idea that we should alert the universe that there is a habitable planet populated with intelligent creatures. British theoretical physicist Stephen Hawking is an outspoken critic of METI, echoing the concerns of Gertz and pointing out that an encounter with alien beings would more likely resemble the Roman Conquest than a meeting with a peaceful entity like the one from Stephen Spielberg's movie "E.T. the Extra-Terrestrial."
"Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach," Hawking speculated in 2015.
The fear about a violent, conquering force of rampaging aliens isn't without merit; when our planet's very existence is at risk -- even if the danger is extremely unlikely -- why would we advertise our presence? Would it be like dropping a bucket of chum in shark-infested waters? Do we really want to find out?
So, yes, these arguments alone should be enough to make us want to switch off our radio transmitters. But METI advocates, like Seth Shostak, Senior Astronomer of the SETI Institute, points to the potential benefits to mankind if we were to establish a collective effort to send messages to the stars. Chiefly, Shostak points out that having a fear of these hypothetical intelligent aliens is just an assumption based on our history. Just because humanity has a violent past, it doesn't necessarily mean other life forms would have evolved in a similar way.
"The universe beckons, and we can do better than to declare that future generations should endlessly tremble at the sight of the stars," he concluded in a 2015 New York Times article.
ANALYSIS: Why Would Aliens Invade
Shostak argues that to not transmit signals could limit technological developments, though I don't share this concern; it could be just as well argued that the lack of development in the field of METI could be offset by huge developments in passively seeking out signals. In the process of boosting our sensitivity to artificial signals, we could make huge gains in new radio astronomy techniques that will have very real spin-offs for science.