Geology expertise helps scientists find Earth-like planets

University of British Columbia geologist Brendan Dyck has leveraged his expertise in planetary formation to help scientists identify exoplanets that might support life. Astronomers have so far identified more than 4000 exoplanets, with others waiting for confirmation. Some of those planets are orbiting stars in what is believed to be the habitable zone and could sustain life. Dyck is using the geology of early planet formation to help identify exoplanets that might be capable of supporting life.

Dyck says that discovering any exoplanet is exciting, but the key thing scientists want to know when a new exoplanet is discovered is if there are smaller Earth-like planets with iron cores among the exoplanets. Those planets are typically found inside the habitable zone of the star they orbit at the proper distance to support liquid water on their surface.

While finding a planet orbiting in the habitable zone is a good way to sort through thousands of candidate planets, simply orbiting in that zone isn't enough to guarantee habitability. Scientists point to Mars, which does orbit in the sun's habitable zone but any water it had has long since dried up. Dyck says the geology information of these rocky planets could play a role in narrowing down the search.

The findings of this study show that if scientists know the amount of iron present in the planet's mantle, they can predict how thick the crust will be and whether liquid water and an atmosphere may be present. He says it's a more precise way of identifying new Earth-like planets rather than relying on their position in the habitable zone alone.

Dyck says planets with a larger core form thinner crusts, while planets with smaller cores form thicker iron-rich crusts like Mars. The thickness of the planet's crust will dictate whether it supports plate tectonics and how much water and atmosphere it may have. Water and the thickness of the atmosphere are key to life as we know it.