NASA finds 10 new ‘Earth-like’ worlds
Astronomers using the Kepler space telescope have detected 219 possible new exoplanets in our galaxy, including 10 relatively small, rocky and possibly habitable planets similar to our own, NASA announced Monday.
These are the last additions to the catalog of exoplanets compiled during the first phase of the Kepler mission, when the space telescope scanned some 200,000 stars in the Cygnus constellation in an effort to find worlds beyond our own. The official catalog now contains 4,034 total “candidates” — tiny blips in the data that are thought to signal the presence of a planet around a star. Of these, 49 fit squarely into their star’s “habitable zone,” that Goldilocks region where liquid water can pool on the surface and life may be able to thrive.
The Kepler space telescope was launched into orbit around the sun in 2009. Its charge: Take a census of a small slice of the Milky Way in an effort to understand the “demographics” of our galaxy. How many stars are like our sun? How many of those host planets? How many planets orbit in the habitable zone? Is there anyplace else in this vast universe that living beings might call home?
In its first four years, Kepler surveyed just .025 percent of the sky. And for every potential planet detected, NASA estimates that 100 to 200 lurk beyond the telescope’s reach. Given a little time and some sophisticated models, scientists will use the Kepler catalogue to estimate how many stars in our galaxy could host an “Earth 2.0.”
Based on how many habitable-zone planets have already been identified, Caltech astrophysicist Courtney Dressing thinks that number could be sizable.
“I, for one, am ecstatic,” she said at a news conference Monday. “The important thing for us is, are we alone?” added Kepler Program Scientist Mario Perez. “Kepler today tells us, indirectly ... that weare probably not alone.”
This is the eighth update of the Kepler planet catalogue and the most thorough survey of the space telescope’s data to date. Of the 4,034 candidates, more than half have already been confirmed as exoplanets and not the result of miscalculations or false signals. Kepler research scientist Susan Thompson, the lead author of the catalogue study, said her team is confident about all 10 of the new “Earth-like” planets found in their stars’ habitable zones.
Several of these planets orbit G dwarfs — the same species of star as our own sun. And one, dubbed KOI 7711 (for Kepler Object of Interest), is a possible “Earth twin,” a rocky world just 30 times bigger than our own and roughly the same distance from its star.
It’s too soon to say whether KOI 7711 truly merits the label “Earth-like,” Thompson cautioned. Kepler is incapable of determining whether an exoplanet bears an atmosphere or liquid water. If aliens were observing our solar system using a similar instrument, they might think it contained three rocky, potentially habitable worlds — Venus, Earth and Mars. “But I’d only want to live on one of them,” Ms. Thompson said.
A second research group combined the Kepler data with measurements from ground-based telescopes to calculate the approximate sizes and compositions of 2,000 exoplanets. They found that smaller worlds, the kind that Kepler was designed to detect, fall into two distinct groups: rocky planets that could be up to 1.75 times the size of our own, called“superEarths ,” and gaseous “mini-Neptunes ,” which lack a solid surface and are 2 to 3 times bigger than Earth.