QUESTION OF THE MONTH
WHAT WOULD HAPPEN TO HUMAN EVOLUTION IF WE LIVED IN SPACE PERMANENTLY?
SOPHIE, VIA EMAIL
GETTY IMAGES X2, ALAMY ILLUSTRATION: HARRIET NOBLE
If humanity suddenly had to abandon Earth on a fleet of space-arks, we would probably go extinct before evolution by natural selection had time to alter our bodies to cope with the new environment. Even if we assume that air, food and water could all be synthesised and recycled indefinitely, a microgravity environment currently causes astronauts aboard the International Space Station to lose about one per cent of their bone density each month, even with strenuous daily workouts. After a few years of this, everyone would be suffering from severe osteoporosis. If our voyage took us into deep space, we would also need to worry about radiation. Galactic cosmic rays would bathe us in roughly 250 times the normal background radiation we receive on Earth and a single solar flare could be strong enough to cause radiation poisoning.