Space germs: How can we avoid contaminating other worlds?

The following is an extract from our Lost in Space-Time newsletter. Each month, we hand over the keyboard to a physicist or two to tell you about fascinating ideas from their corner of the universe. You can sign up for Lost in Space-Time for free here.

When astronauts on the Apollo 11, 12 and 14 missions returned to Earth, they were kept in quarantine for three weeks – along with the lunar samples they’d collected – to make sure they hadn’t …