Hi Dick,

I think the issue is how long do we have before the odds of continued survival are strongly stacked against us. A 'dark age' following our modern era could slow all of this down considerably, but that would rule out interstellar travel. Given the unlikelyhood of total extinction with current weaponary, it seems that a dark age is more likely to occur prior to the next millenium than some accident that destroys humanity.

On the other side, it wouldn't hurt to start developing space colonies in places like the Moon. I don't think that the Moon would be any safer (and far less practical) than some deep bunkers in the earth, however the concept of spreading out from earth and into our solar system isn't something that I consider so far fetched. Perhaps in a few hundred years we could produce mini-biospheres on places like Mars, Europa, etc that could sustain life for millions of years. This could at least give us a chance to reach the stars despite what occurs in one of the terrestial civilizations (e.g., earth).

Warm regards, Harv