Algae that can signal me from 50 light years away is algae worth studying.
This is big in pop culture, but not really true. Broad spectrum omnidirectional TV and radio signals are pretty weak on an interstellar scale. Even from a few light years away, you’d need a radio telescope network that’s roughly the diameter of our solar system to be able to detect our signals - using anisotropy it’s not impossible, but we’re definitely not a big unmistakable beacon of radio transmissions.
The most likely way that someone will discover us, or that we’ll discover someone else, isn’t actually any sort of technological broadcasts at all. With sensitive enough telescopes and spectrometers, we can get a glimpse into the atmosphere of extrasolar planets through analyzing the changes in spectra during transit events where the planet gets in front of their star from our view. From there, we can say “aha, they have various polutants in their atmosphere that don’t occur naturally, there must be some sort of post-industrial age civilization there”. So if there’s an alien species who can see straight on to our solar system’s ecliptic (where the earth will transit the sun), that’s how they’ll find us.
As far as the beacon question, sure, why not. It’s worth the risk. Sure, we might invite a hostile species - but what exactly do they need us for? If they have the ability for interstellar travel, they have resources beyond anything us. Whatever material resources they could find on earth, they could find on asteroids or other planets. They probably have robotics technology sufficient that slavery isn’t appealing. So what is it that they’re going to come over and destroy us for? If they’re incurious yet hostile they probably simply won’t care that we exist. If they’re curious, then finding a new intelligent species is probably a pretty big deal and they’d love to meet us.
Finding life out there would be the greatest discovery of humankind. There’s no greater purpose than the quest for knowledge, and this would be the biggest advance we could ever have. Even if there’s a small chance it leads to our extinction at the hands of some interstellar dicks, it’s worth a shot. I’m amazed that this poll is so negative - you’d really decline the biggest discovery ever because of a relatively small risk?
I love bacon!
or making a bio-fuel from. Or wosrse, a salad. I’d prefer to be at the top of the food chain.
I have enough problems dating as it is. I don’t need competition from Martians as well.
Stranger
Maybe Martian women would be into your hump.
I I think we need to find more intelligence on Earth before we go looking for it somewhere else.
The potential benefit outweighs the potential risk by many orders of magnitude. I voted yes.
I take exactly the opposite tack, Rigamarole. The benefits-well, we’ll probably figure out a lot of all the cool technology they might offer on our own, sooner or later (after all, if they can do it, it is a 100% doable possibility). The cost would be the loss of our lives, our civilization, and our future. For me that simply isn’t worth it-can all the Pollyannas in this thread really say with a great deal of certaintly that there aren’t any (many) Berserkers wandering around the universe somewhere? That xenophobic and/or exploitative interstellar civilizations are very few and far between?
Of course, as Senor Beef indicates, it probably would be moot anyway, as passive detectors of a sufficient size and sensitivity could probably make note of us from hundreds of light years away (heck we got such things on our drawing boards now).
Mods, I realize that this is verging close to GD territory-perhaps the thread should be moved there.
We have no future unless we make major, sweeping changes to our planet. We really have nothing to lose.
If I were a malevolent alien bent on wiping out other races, what would be smarter? Building a whopper of a receiver and scanning everywhere, or sending probes to every star in the galaxy, with the probes being intelligent and resourceful enough to independently wipe out life when they find it?
Seems to me just waiting around until you pick up a radio signal would be risky, since by the time you receive a signal, the race that sent it could be going through a rapid technology spurt, and they just might come looking for you.
OTOH, if you sent out death probes to every star system, the probes could proactively wipe out any future pests before they get far.
So, a smart, but murderously xenophobic race would probably already have a death probe in our system, and we should probably have been sterilized by now.
Ergo, we’re safe! 
For an interesting speculative book on this subject see Peligrino and Zebrowki’s book “The Killing Star”.
Spoiler Alert:
The idea of the book is that there are plenty of advanced civilizations in our galaxy, but the ability of such civilizations to construct near-light speed interstellar spacecraft results in a situation much like armed and possibly hostile people stuck together in a dark room. If you are so foolish as to make your presence known, the best course of action for every one else is to immediately kill you. Because there is, in this scenario, no practical way to protect yourself.
The author’s reasoning is that the fantastic kinetic energy of an interstellar space craft makes it the most devastating weapon ever devised. Not only can one space shuttle-sized ship wipe out an entire planet (simply by crashing it into an Earth-like planet, the oceans could be boiled), but it’s speed ensures that the attack would be for all purposes, undetectable until it’s far, far too late to mount any countermeasures.
Since any civilization which possesses such technology is the gravest possible threat to the survival of one’s own species, the safest course of action upon discovering another star faring civilization is to wipe it out ASAP.
Personally, I think this idea is highly unlikely. I voted “Other”. My understanding is that the radiation generated by slamming a space craft into interstellar hydrogen at near light speed would almost certainly kill any crew, and fry the guidance and control electronics. Not to mention that the technologies required to make sufficiently powerful engines for interstellar travel may prove too difficult for anyone to master.
I think “The Killing Star” raises an interesting and valid point though: If it is possible that there is a hostile and advanced civilization within contact distance, is it reasonable to risk the survival of the human race based on our feeling that our good intentions are the norm?
Walt
Looking at it from a human perspective, I can’t imagine any government investing the time and resources in creating a craft strictly for genocide of a species we know next-to-nothing about. It’s the equivalent of the US immediately nuking any country that looked like it might develop its own nukes, just in case. There’d be so much uproar over it, and so little benefit (to the politicians making the decision, if not to the human race), that it seems far-fetched.
Guess I am thinking more long-term, and not specifically early 21st century. While your statement is arguably true as of this moment in history (tho I specifically reject your implication that we can’t do it ourselves), what if we un-fuck ourselves as a species and civilization, and have a healthy, vibrant & innovative culture in place in c. the year 2501? By then we might have a clear vision of How to Do Things, even if we aren’t quite up to the required energy levels, thus not needing the “help” of any ET’s.
hougaswd, they’d only need an unmanned projectile to do the trick, but yeah. Look, I’d love to believe that all spacefaring civs are peaceful and benevolent (and in fact in isolation I’d say that that would be the natural trend), but if space turns out to be as primal a Darwinian battleground as most of our ecosystems are, I think our best bet is to learn How Not to Be Seen.
Of course, the precise potential problem is that they aren’t human (above emphasis mine). We have no idea what their motivations are precisely because (a) there is no/won’t be any direct instantanous and ongoing communication (read: diplomacy) between us and them, and (b) we don’t share the same DNA and thus same interpersonal predelictions which allows us to grok the motivations of other people & countries. The aliens will be pontificating unto the void (just like we would, assuming we’ve detected them too), and, since said void has no recognizable face (human or otherwise), the inhibitions to not attack wouldn’t be there for the most part. And, just to be clear, I find the thought of a vibrant living planet being wiped out instantaneously absolutely abhorrent.
One more thought before I go to bed after a long day: this could end up veering very close to all that Prisoner’s Dilemma stuff, with the additional complicating factor that we truly would not be able to get inside the head (as it were) of our fellow prisoner’s mind and predict what he would do (“Oh Sam and I go way back he’d never sell me out.”). And tit-for-tat likely wouldn’t apply either (would a third civilization be near enough to detect the aftermath in a time frame which would make it meaningful for them?).
I’d be in favour, because I think the possibility of anyone visiting us is infinitesimally close to zero, but I think it would be a generally good thing for intelligent races in the universe to be able to be aware of each other.
No.
Why would a friendly species bother to respond to the signal?
It wouldn’t be interesting to you if we found another intelligent species out there?
Edit: And the same could apply to them. Life on other planets is sort of an interesting concept, possibly even more interesting than sitcoms or knitting.
Why wouldn’t they? If we received a signal, we’d respond (despite Dr Hawking’s advice).