Under pressure: what might life look like on another planet?

00:00 09:05

Adam Frank has narrated this article for you to listen to.

Over the past three decades, astronomers have discovered planets orbiting Sun-like stars throughout the universe. This discovery ended 2,500 years of debate about whether worlds existed beyond our solar system, but it came with a shock. The most common kind of planet in the universe is the type of world that doesn’t exist in our small corner of the cosmos: what astronomers call ‘Super-Earths’ and ‘Sub-Neptunes’, planets with much greater masses than ours and which could, in theory, sustain life.

Astronomers concluded a little over a decade ago that every star in the night sky hosts a family of worlds. Importantly for the search for life, one in five of those stars will have a planet in the ‘Goldilocks’ zone (sometimes referred to as the ‘habitable zone’). That’s the band of orbits that are just right for water to pool up on a planet’s surface into puddles, lakes and oceans.