Average (mean) lifespan of communicating species is surely an astronomical figure; in only a couple hundred years humans will likely reach a technological level which makes them borderline impossible to eradicate. Much like the bacteria which took hold on Earth and became impossible to root out by any means short of the Sun swallowing the Earth, once intelligent life reaches a certain technological level it creates a new paradigm that can never go back.,(reply>), Thats the exact human ego that destroyed us.. smh.,(reply>), How do you figure that in a couple hundred years we will be almost impossible to eradicate? What's your bases ?,(reply>), They found radiation on planets such as Mars. And apparently Mars was said to be habitable for life millions of years ago. What if nukes killed Martians off? Or if they're still there. We have tons of pictures of Pyramid-like structures on Mars. And they found water underneath the surface on both the Moon and Mars. They're saying there's life underneath the surface, that might just be classified information. Who knows,(reply>), It's only astronomical if you assume its astronomical. For all we know, next week nukes can be flying over our heads and our species will be gone