The Quest for Life

Has our civilization been around for 6,000 years (Ancient Egypt)? 200 years (the birth of America)? That's a big difference and it matters to the end result. The real point of interest is the discovery of radio. That marks a technological level sufficient to communicate. For us, that is about 100 years. So far…

Great civilizations have collapsed many times in hour history. But for human civilization as a whole, these have only been setbacks. We may lose some culture or technology, but it always comes back and gets even more advanced in the next rise to power.

A similar setback in the future would not be the end of our ability to communicate. The end is really the extinction, or near extinction, of Homo sapiens as a species — losses sufficient to halt the transmission of culture from one generation to the next. How long until that happens?

• Asteroid and Comet Impacts
• Human Extinction