Eminent physicist Stephen Hawking warned recently that humanity needed to colonize other worlds in order to avoid the risk of being made extinct as a result of a catastrophe on Earth. It comes amidst much talk about manned missions to Mars; expeditions that plan to set up new settlements with a no return to the mother planet policy, permanent habitats.

I get the idea that humans are destined to explore and that the boundaries of the Earth have nearly been breached in all directions, save perhaps the ocean floors. By all means, let's explore because it is inspirational, collaborative and may, for a period at least, focus all people on a single project. I remember the excitement of being present in my Grade 5 classroom as Armstrong placed his foot on the lunar surface. I remember the following year, as Apollo 13 ran into trouble, mulling over all the engineering options with friends in the school quad. Imaginations ran amok about events at what seemed to us, an impossible distance.

But if we really want to avoid extinction on the planet we evolved on, why not start at home. You don't need to run away into the cosmos at huge expense and risk if you do the hard yards of eliminating nuclear weapons entirely here. Likewise, money will buy the technology to survey Near Earth Objects more closely, and to put platforms into space that can launch probes and weapons to divert pesky asteroids that might do us harm. Across the range of potential catastrophe's there are few that sheer determination and serious financial backing can't ameliorate to some extent. The odds will lengthen on our extinction.

By all means let's go to Mars. But let's not throw out the baby while we are doing it.