From Todd Bailey, Penarth, Vale of Glamorgan, UK
Kelly and Zach Weinersmith consider challenges to living on Mars. Fictional futures sometimes improve the Martian climate by moving the planet closer to the sun, but the more I learn, the less plausible these scenarios seem (16 November, p 48).
Back-of-the-envelope calculations suggest that moving Mars into Earth’s orbit would require energy equivalent to three full days of the sun’s total output. If we could afford at some point in the future to devote one year’s worth of global energy production to the task, at the current rate of growth we will have to wait for 12 trillion years. I won’t be holding my breath.
