For the last 6 years, the Kepler spacecraft has been scouring the galaxy for habitable planets similar to our own. After narrowing down a lengthy list due to incompatibility or faulty data, the scientists have settled on 20 planets that appear to be the most promising yet for interstellar habitation.
What makes a planet habitable?
The newly identified exoplanets could be our best attempt to date at finding a habitable planet. Why? The 20 planets on the NASA short list have a 70-80% chance of habitability based on a number of key criteria: proximity to sun-like stars, orbit length and the potential for liquid water and livable temperatures. These planets also appear to sit within the now-expanded “Goldilocks Zone” of their respective stars—that is, they aren’t too hot or too cold, but potentially just right.
The Goldilocks Zone parameters have previously been based on Earth’s life-supporting proximity from the sun. But that’s up for reconsideration as some of the newly discovered planets appear to be much closer to their dimmer stars, successfully maintaining a habitable climate and potential for liquid water.
Life on Earth is a sensitive balance of the right conditions—conditions that have not yet been replicated anywhere in the discovered universe. Our atmosphere, plate tectonics, liquid water and ideal distance from the sun have enabled and maintained life in all its delicacy.
While Kepler’s discoveries have shown several promising planets, the most promising of them all for hosting human life is KOI-7923.0. With a 395-earth day orbit, tundra-like temperatures and the ability to maintain liquid water, the significantly smaller planet may hold the key to present alien or future human life.
However, scientists aren’t ready to name Earth’s twin just yet. Due to technical issues a few years into Kepler’s mission, its incoming data sets weren’t completely clear and dependable. Many of the signals NASA received were wobbly, as the spacecraft wasn’t able to aim its equipment at the planets properly. But now that the team has already ruled out a number of fake readings, these 20 appear to be solid candidates for future exploration.
Interstellar ventures and Mars’ potential for life
The discovery of these new planets isn’t humanity’s first attempt at venturing to deep space. Innovators like Elon Musk have long been eying outer space as a potential host for future human life. The Tesla CEO developed SpaceX to begin opening pathways to deep space and Mars habitation, just in case Earth should ever become compromised. Over the next several years, he intends to lay the foundations for sustainable life.
But despite Musk’s vision for Martian life, the exoplanets on NASA’s radar seem more likely candidates for life than Mars. With its 687-day orbit, average temperatures of -80 degrees F/ -60 degrees C, and a 95% carbon dioxide atmosphere 100 times thinner than Earth, Mars poses numerous challenges for human settlement.
Does Kepler’s interstellar discovery hold the key to life outside of our solar system? The jury is still out. However, if appearances hold true, these planets could be capable of hosting life. And as scientists and innovators continue to venture beyond Earth’s borders, one thing is evident: life as we know it may not be as grounded as we’ve always imagined.