Opening today is the remake of the 1951 science-fiction classic, The Day The Earth Stood Still, starring Keanu Reeves and Jennifer Connelly and directed by Scott Derrickson (who Science Not Fiction interviewed earlier this week). In the original movie, Klaatu came to inform the Earth that the galactic community was Not Happy about the stockpile of nuclear weapons humanity was building up. This time around, it’s the erosion of planetary biodiversity that has our alien neighbors ticked off. It’s actually not an unreasonable motivation — many astrobiologists suspect that bacterial life may be somewhat common in our galaxy; even in our own solar system there are several possible habitats, including Mars and Jupiter’s moon Europa. But they have speculated that more advanced lifeforms are exceedingly rare: consider that for 85 per cent of the 4 billion years life has existed on Earth, no multicellular creatures arose. So the rapid extinction of many species here would be a significant blow to the biodiversity of the entire galaxy, not just the Earth’s.
