David Blenkinsop wrote:
> Compared to such grand space-trashing ideas, I still wonder if a
> relatively mundane idea might be worth thinking about, namely the chance
> that intelligence might survive preferentially on quite "large"
> planets as compared
> to the Earth. If a solid planet with the Earth's density were
> twice as large
> in overall dimensions, it would then have eight times the
> mass of the Earth..
> Presumably, the atmosphere would then almost have to be much
> thicker, giving
> any surface inhabitants much better protection against
> radiation events than
> we have. I understand that small, long-lived stars are prone
> to solar flares,
> and we've talked about gamma ray bursters, too, so maybe you
> really *need* the
> extra shielding if surface dwelling technology builders are
> to generally have a good chance of evolving.
There is some question about whether such planets exist (unless you are including gas giants in your analysis, which is a completely different issue). But even granting that, there is no serious barrier to space travel in the long term.
Certainly, a species on such a planet isn't going to get very far with the kinds of rockets we have now. However, there are two easy ways out of this trap:
On a more fundamental level, let me point out that both of these are short-term solutions. Do we really think that any possible planetary environment could keep a technological civilization stranded for a million years? How about ten million? A hundred million?
To explain the Great Silence we need more than a temporary impediment to progress. We need something that makes it absolutely, completely, utterly impossible for a typical life-bearing world to produce a civilization like what we expect ours to be in another 100 years.
Billy Brown, MCSE+I