New Study Says It's Time for Us to Expand Our Criteria for Finding Alien-Life-Hosting Planets
Drake Equation aside, there's one big obstacle to finding exoplanets that may support life: our own lack of imagination.
For years, scientists have labored under the assumption that a planet has to be small, rocky, orbiting in the "Goldilocks zone" around its star, and possess plate tectonics (like Earth) in order to support life. But it turns out planetary science is much more complicated than that, and there's new research from Rice University to prove it.
One of the big revelations from the study is that the "habitable zones" around stars aren't the only places conditions for life can arise because it turns out that close proximity to the sun isn't essential for the existence of liquid water.
According to geophysicist Adrian Lenardic, one of the authors of the paper:
"It used to be the thought that life could only exist in a narrow zone near a planet's star because you need to be there to maintain liquid water. Then, we send Voyager out to a moon of Jupiter and, lo and behold, it shows strong indications of a subsurface ocean. That's because there is another energy source that did not get its proper due—tidal forces from the intense gravitational pull of Jupiter. This has opened up the range over our own solar system in which life can exist, and I think a lot of the gist of the forthcoming papers is that much of what we're seeing is expanding the zone and expanding our thinking about the conditions needed for life."
Another major discovery is that planets don't need plate tectonics to keep control of their temperature and ensure the existence of liquid water—volcanic activity and other forms of tectonics can accomplish the same thing.
All of this challenges long-held assumptions about what a planet needs to be habitable and capable of supporting extraterrestrial life.
"We're at the first point in our history as humans where we might actually have some observations from other planets that we can use to test any of these ideas about life beyond our own," says Lenardic. "It can be easy to be Earth-centric and assume that life requires a planet like our own. But what we are seeing within our solar system is causing us to question this."
Want to join the search for potentially habitable planets? You can help NASA and Google identify new ones by downloading their open-source algorithm and trawling through the data from the Kepler telescope!