Hostile Aliens or Friendly Aliens - Two Sides of the Discussion

In the 1970's the Voyager spacecraft left Earth carrying plaques with information about the human race, our culture, our art and our location. An open invitation to drop by for a visit. Long before the Voyagers left the launchpad, we were advertising our presence.

About 100 years ago, humans started broadcasting radio waves that are still traveling outward from our planet at the speed of light. Within 30 years, television broadcast followed. Within that 100 light year bubble, we have already announced our presence to anyone listening. Will they be friendly? Will they be hostile? Will they care at all?

The second episode, Aliens of Into the Universe with Stephen Hawking has sparked conversation and debate, sometimes even ridicule in the main stream media. Hawking presented us with a wide variety of possible life forms. His opinion that life, statistically, must exist elsewhere in the universe came along with a warning that we might want to think twice about advertising our presence.

Like Stephen Hawking, I am a cautious pessimist, my friend, Gene, is a cautious optimist. Here's a revised outtake of our discussion:

Resources

Gene: What would they want of ours? There's nothing a star-spanning race could want from us that they could not find anywhere else. The only thing (as far as we know) on Earth that's unique to our Solar System is liquid water. It would be a simple matter for 'aliens' to obtain a quantity of ice from any other number of places in the Solar System and distill it. It seems likely that any predatory contact would not be focused on our resources, but perhaps on the planet as a whole. I discount that for two reasons. Our planet's unique position in what we call the 'habitable zone' certainly makes it distinctive, but that assumes the putative conquering race is similar to us in its environmental requirements. Secondly, like it or not, we're in a backwater of the Milky Way. In effect, they'd be coming a long way just to take over the planet. I think a more likely scenario is that we're *discovered by an unmanned probe, or an expeditionary group.

Lisa: While Hawking's warning showed a civilization that could harness the power of a sun and warping through a homemade wormhole, that may not be the only way to get here. We don't know how they will get here but they may come without terrifically advanced technology. Simple bombardment of a planet with nearby asteroids may be their most advanced weapon.

Resources our system has to offer include the asteroids but more valuable is our sun itself. We do know that stars aren't very dense in our neighborhood. Within the 100 light year bubble of our broadcast signal there are roughly 15,000 stars. Two thirds or more are part of binary systems making them unlikely homes for a stable civilization. Of the rest, some are old, some are too hot or too cool for human-like species. While most stars are main sequence, there may not be so many G type stars that are relatively young. The three terrestrial type planets in the optimal zone for liquid water may be even more rare. While modifying a barren planet to be able to support human-like life is possible, doing so in under 10 thousand years is unlikely. Earth may be an extremely rare resource, unobtainium itself.

Maybe They Just (Don't) Like Us

Gene:Why would they like us? A good question. Right now, I can't see any reason why they would. We certainly have not shown our best behavior almost from the outset. Our news is full of violence, our entertainment is often simpleminded or bloody. I can only hope that some race that encounters us would be willing to treat us as we treat our immature children. We have no reason to believe our history is any different than theirs would be, at a similar place in their history. I can understand your point of view, and if I were more pessimistic I would probably adopt it. Right now, though, we're not strong enough to threaten any one. We give our kids a chance to grow up - the best we can hope for is similar understanding.

Lisa: Our broadcast history portrays a violent race. Virtually real time images from Nazi Germany to the Iraq war, from genocide in Darfur to genocide in Bosnia, we show ourselves to be, right now, a violent species who can't live with each other for ideological reasons or even the color of our skin. Who would want us escaping into a peaceful neighborhood, messing up the landscape? Or maybe the neighbors have a hankering for a new batch of slaves. Or maybe they just want the whole neighborhood to themselves. Whether as peacekeepers or plunderers, our own existence may be incitement enough to draw hostile actions from our neighbors.

On Seeking Contact

Gene:I don't believe in actively seeking contact even if the odds favor you unless you have to. I have no problem with listening for other civilizations; I have no problem with greeting civilizations that come here with open arms. After all, if an interstellar ship set down on my doorstep tomorrow, you can be sure I'd try hard not to antagonize the crew. They've already established their technological superiority. Game over. However, I don't see any purpose in announcing to the galaxy at large, "Hey! Over here!"

Lisa: It's too late to hide now. We have been yelling our heads off for 100 years. It might be wise to stop broadcasting now but we'll never be able to agree to anything unless we learn to stop hating and killing each other first. Can we build defense? Again, that takes more cooperation than humanity can muster. My fear is that the reason we don't hear anyone else when we listen for signals is because some hostile civilization shuts up any potential competitor as soon as they start making noise. Let's hope that's not the case.

Star distributions from:

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980402c.html

Abell, Morrison, Wolff. Realm of the Universe. 4th. edition. 1988. Saunders College Publishing. Philadelphia. PA, USA

Aliens

http://dsc.discovery.com/videos/stephen-hawkings-universe-fear-the-aliens.html

http://www.cnn.com/video/#/video/bestoftv/2010/04/27/ac.gupta.tyson.aliens.cnn?iref=allsearch