Good discussion. Love the science. Space and cosmology are fascinating, but I'm not sure about the value of a trip to Mars though. Looking at what's ahead of us here on Earth, the case for human travel to Mars looks increasingly like a legacy of 20th century hubris, which consequences we now have to mop up. I get the thrill of having a biped walking on another planet, but it will necessarily come at the cost of other scientific programs. I'd rather put that money on missions to explore further the solar system, other planets and their moons. Sending robots is not as exciting, but we're increasingly spending most of our "reality time" on screens, so the flesh could eventually stay at home and the thrill be the same. Consider drone pilots. I'm sure they'd rather have blue sky around them, but I bet it feels pretty real when they drop a missile.  <br><br>Life on Mars won't be that exciting anytime soon. A long-term colony on Mars will have to be underground given the lack of atmosphere, cosmic rays, etc. So "life on Mars" will feel like being in a submarine, where any sortie is a full-on mission. A good proxy is to consider what would be life in any of the most hostile spots on Earth (eg, Antartica) minus the atmosphere. Because terraforming is a pipe dream: Mars gravity not change so whatever we pump out the atmosphere won't stick. So glass bubbles it will be. Great. Just a more comfortable submarine. :-)