Habitable planets

1/5 of stars surveyed had planets in their “Goldilocks,” or habitable zone.
Image: Shutterstock

Most likely, the day will come when we earthlings will have to up and move to another planet. Whether that’s because we’ve completely destroyed this one, because we simply need a second home planet, or elsewise remains to be seen. But one thing is for sure: finding a habitable planet might not be as hard as we thought.

In the past three years, the NASA Kepler Space Telescope has surveyed more than 145,000 stars and identified 3,538 planets orbiting said stars. Of those stars, an estimated 22% had planets roughly the size of Earth orbiting at a potentially habitable distance. About 104 planets were identified as being in the “Goldilocks” zone, an orbit distance that is similar to Earth’s.

And, about a quarter of those 104 planets were less than twice the size of Earth, which increases the chance that they will be rocky rather than gaseous.

A team at UC Berkeley analyzed some of the Kepler data, looking at 42,000 stars similar to our sun. The team, led by Eric Petigura, found that there were a total of 603 planets orbiting those stars, and of those planets, ten were roughly the same size as earth and had similar amounts of sunlight.

“What this means is, when you look up at the thousands of stars in the night sky, the nearest Sun-like star with an Earth-size planet in its habitable zone is probably only 12 light years away and can be seen with the naked eye. That is amazing,” Petigura said.

There are tens of billions of Earth-like planets in each galaxy. And the universe is made up of many galaxies. That’s a lot of potential new homes should the need arise. And while this news is indeed exciting, it’s also important to keep in mind that many planets may end up being too big and hot to support life, even if it will support water.

The questions we need to be asking next are these: Are these planets actually habitable? Can they support human life? What are their atmospheres like? Is there other life already inhabiting them? Are they rocky or gaseous?

We don’t have the technology yet, but we should soon. We now know that there are lots of potentially habitable planets out there—now we’ve got to determine which of them could actually support human life. There are plans in the next half-century to explore those options, analyzing planets’ atmospheres and surfaces to truly get a better idea of what our future may hold.