I love your articles, A.S., but need to comment on this one. Humans in our current form evolved in 200,000 years to live comfortably on 10% of this planet - the other 90% is too hot, too cold or covered with salt water. Do we really want to use inconceivably advanced technology and economic resources to move our current forms to terraformed planets? We will migrate to a new form of our existence long before we do that.