Astronomer royal calls for 'Plan B' to prevent runaway climate change

[muriel_volestrangler]

43. "energy or materials ... are actually quite abundant in space" - no, materials are not

That's the meaning of the word - 'space'. There's nothing there. Rocks are available at the other end. With a huge effort, you can convert them into useful objects. But you need to build rockets here on Earth to get there first.

"On the other hand if we were to compare relative energy density of the time when "Conestogas" were the fashion and the energy required to build one, I think that you'd see that we're well within that same ratio today. "

Really? Why do you think that only multi-millionaires can afford to get a few days in space, let alone get another rocket launched with them that could take them as far as the Moon, whereas average people were able to scrape enough together to build or buy a wagon? It's because the resources that go into building a rocket capable of lifting several tonnes to orbit (and you need tonnes per person - all the life support) are huge. Then you need another stage, also in orbit, capable of carrying people in safety, and landing it. Only then have you got to the materials you call 'abundant'. Curiosity cost $2.5 billion and that's just a few tonnes of equipment without any humans. Multiply it by 10, and you might keep a human alive. Multiply that by a billion, and you're analogy of 'moving people to the life raft' would start to be relevant - you'd move a seventh of the world population. But that's $25 billion billion, or nearly 300,000 times the yearly Gross World Product of $85 trillion.

This is why we've got to fix the planet first. The equivalent in your liferaft analogy is that we could throw a piece of paper overboard and say "look - we've lightened the load!". And all to get to somewhere that is orders of magnitude harder to live in. You could stay on Earth and fix everything for the people you were going to send to Mars or wherever for a tiny fraction of the effort.