Quote:
Originally Posted by photon
True, but once that life gets off the rock and starts to colonize the surrounding area, it will start to grow pretty quickly.. similar to the exponential growth on earth. So while it may take humans tens to hundreds of thousands of years to get off the earth and start to colonize the solar system, it would only take another 500,000 years to have at least sent probes to the rest of the galaxy (through Von Neumann probes). And given the age of the galaxy, there's been plenty of time for many many civilizations to have risen, colonized the galaxy, and gone away.. the question then becomes why haven't we found any remnants? Von Neumann probes, Dyson spheres, something.. Though there's lots of reasons why we couldn't see them, or maybe even intelligence almost always destroys itself before it reaches that point... |
There may be evidence right in front of our face, but we can't see it, detect or even imagine it existing. We look for things that we can think up, like these probes and spheres you mention, but 'they' may have used something that is just beyond or imagination or technological understanding. (pretend that we live on an island circa 5 thousand years ago; perhaps we'd imagine an advanced civilization from the past visiting our island in fancy boats, as we wouldn't be able to imagine them using aircraft.)