An invitation.... FROM OUTER SPACE!

I'm sure most of you know about SETI. The Search for Extraterrestrial Intelligence.
These chaps use radio telescopes to listen for signals that may be coming from alien civilizations. This has been a passive search, meaning that we simply sit here, point our ears to the sky and wait for signals to arrive.
So far it has been pretty quiet as we have not been able to detect any signs of intelligence.
Some people are now suggesting that we should go from passive to active. So instead of simply listening, we should start to broadcast signals to other star systems in hope of making contact.
Some scientists, including Stephen Hawking, have voiced their concern over this, and with good reason.

So why is this a bad idea?
Simply because we don't know what's out there.

There are two camps of thought with this.
One sees aliens as the space hippies that smoke AstroTurf and will help us evolve into spiritual galactic citizens.
The second camp it that suggest that aliens are a possible threat that sees humans as ants crawling over their picnic basket.


To make sense of these scenarios we must take into account is evolution. The laws of evolution are universal and therefore we can make an educated guess of what alien life would be like.

You cannot evolve space travel without co-operation. The pressures of evolution are such that without symbiosis and co-operation, you cannot get very far. Same as humans learned to gather together to hunt, farm, look after each other, the same would need to apply to an alien race.
Aggression can only take you so far in evolution. Co-operation and fairness are absolutely essential for development.

Now comes the other side of the story.
In order to be able to advance, you also need pricks. You need to have the ability to be selfish and forcefully compete against other life forms for resources.
In order to obtain an intelligent life form, you need evolutionary pressures. This, more often than not, means that a species needs to aggressively subdue or eliminate another species.
Evolution is a cycle of death and adaptation. Only those who can adapt their way through will survive.
If we were to meet, our encounter could be disastrous. They may see us as a threat or even a nuisance that needs to be eliminated. Hell! We may even declare war unintentionally.  
Some have even suggested that the reason why we have not heard from anyone else is because they know better than to broadcast their position in case a hostile civilization finds them.
This could solve the mystery as of why if, theoretically, the galaxy is teeming with life, we have not found evidence of it yet.

We also have the problem of intelligence. Our intelligence may be completely incompatible with alien intelligence.
As humans we're very centric on our view, and why shouldn't we be? We simply cannot put ourselves in the head of any other living thing. But now we're starting to understand that intelligence is all around us, it's just not human intelligence.
An alien civilisation may not even recognise us as intelligent or even sentient.

Another possibility is that an alien encounter would be something along the lines of Arthur C. Clarke's 'Rendezvous With Rama' where the aliens complete ignore Earth and humans, simply moving on as if we were not even there.

Personally, I see the idea of sending signals into deep space with our co-ordinates akin to putting your private details online for everyone to see. Chances are you'll be okay, but you're also running the risk of some very bad things happening to you.