A team from the Carnegie Institution for Science believes that scientists should consider an exoplanet's inner dynamics to evaluate its potential to support alien life.
The researchers composed of experts from different fields, including geochemistry and astronomy, urged the scientific community to rethink the current metrics used to flag potentially habitable exoplanets. They said that the conditions that made life possible on Earth were influenced by what is beneath the planet's surface.
What's Inside Counts
Right now, observations of an exoplanet's atmospheric conditions is the first way to evaluate an exoplanet's habitability. However, researchers believe that to truly judge whether it can support life, scientists should investigate how the world's interior affect and is linked to its atmosphere.
To do this, first, scientists must understand the features that made planet Earth habitable in the first place.
"We need a better understanding of how a planet's composition and interior influence its habitability, starting with Earth," explained Anat Shahar from Carnegie Institution for Science. "This can be used to guide the search for exoplanets and star systems where life could thrive, signatures of which could be detected by telescopes."
The researchers argued that the search for potentially habitable exoplanets and extraterrestrial life should be a collaboration between multiple disciplines. To make a proper assessment, scientists must combine astronomical observations, mathematical modeling and simulations, and laboratory experiments that explores the inner conditions of a foreign world.
Earth As The Model In Search For Habitable Planet
The elemental building blocks that lead to the formation of rocky planets like Earth are universal. However, the relative abundance of these materials, as well as the processes they go through, affects the inner composition of a planet.
The inner composition of a planet, meanwhile, dictates environmental features such as the volume of liquid water on the surface and atmospheric conditions.
On Earth, the process of cycling material between the surface and the interior of the planet produces the magnetic field, which in turn protects all life from cosmic radiation.
"One of the big questions we need to ask is whether the geologic and dynamic features that make our home planet habitable can be produced on planets with different compositions," said Peter Driscoll, one of the authors of an article that appears in Science.
The now-retired Kepler Space Telescope discovered over 4,000 candidates and confirmed exoplanets during its lifetime. Its successor, the Transiting Exoplanet Survey Satellite or TESS, is expected to add more to the growing planetary catalog.
As the next generation of telescopes come online, enabling scientists to look for signatures of life in other planets, the team hopes that the effort will help in looking into what is beneath the surface.