. >> guest: arthur c. clarke of coor's road about this in a book called the exploration of space which is a bible in the community. and he has got -- he mentions a lunar colony in the mars colony. he has got the mars colony under a kossel plexiglass don't. and if you look in that you can see all of that vegetation and all sorts of things. that dome would also have to keep radiation which on mars is terrible. but, again, what was to you have? one really bad head and earth is gone. and we just evaporate. what i care? and grandchildren. >> host: than it is not just the volcanoes and the *. any number of things getting enough and. it is lucky we made it through the cold war. >> guest: and tara side and global warming and climate change. absolutely. that all line, we have met the enemy and it is us. >> host: you would have to have a lot of people maintain a society such that when the threat is gone and the earth has settled back down into something like normal -- get of bonds backed chair so that they could start the

. >> guest: you know, arthur c clarke wrote about this in his third back, which is a bible in the community, and he's got -- he mentions a lunar colony and a mars colony and he's got the mars colony under a colassal plexiglass dome and you can see vegetation and automobiles. the dome has to keep out raidation which on mars is terrible. but again, what choice do you have? one really bad lit and earth is -- bad hit and earth is gone and we just evaporate. will the universe care? no. but i care. i've got grandchildren. >> host: it's not just the volcanos and asteroids. you can think of any number of things getting out of hand. it's lucky we made it through the colored war. >> guest: and terrorists. look at the stuff we're pouring into the ocean, and air pollution and global warming and climate change. absolutely. what is the old line, we have met the enemy and he is us. >> host: what i think is you have to have a lot of people to maintain a society such that when the threat is gone, and the earth is settled back down into something like normal, to get a bunch back to earth so that they could s