Dutch Uncle
* Tertia Optio * Defend the Constitution
Well how do we know if it's "rare"? In order for us to know if it's "rare", at least within 1,000 light years radius would have to be explored to determine how it might be rare in the Milky Way.
More and more habitable planets have been discovered constantly.
If we're the only life we can find, then it's rare. How "rare" remains to be seen. Over 50 years of searching. No results. Common sense says it's not too common around these parts.
