Aliens (extra-terrestrials)?

[rado84]

it may be completely impossible for any beings to have such technology

You're very wrong about that. If it weren't for the stupid religion, there wouldn't be the 1000 years known as Dark Ages and right now man kind would be colonizing planets in other solar systems. I know it sounds like a science fiction to you but just think about it. Imagine that religion never happened and science was never forbidden thus letting it follow its natural course. And now think about this:
• the first single core CPU was released in 1993 with clock frequency of 60 to 66 MHz. 22 years later there are more than 64 cores CPUs.
• 22 years ago computers used to be huge in size and heavy. Now you can have a supercomputer in your pocket which you use every day to tag yourself on FB. It's called a "smartphone".
And that's just a short period of time - 22 years. At this rate of technological progress, just think what we could do in a thousand years!

Now, imagine there's race out there that never had the bad luck we had with religion and their science was never forbidden. Whatever technological level they've reached, we're still 1000 years behind - just like we were 2000 years ago when "god" arrived in this solar system.
So saying it's impossible another race to be more advanced than us is joke and unserious, to say the least!